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Bavishi, Abhay J., 2011, “Studies in Heterocyclic Moieties”, thesis PhD, Saurashtra University http://etheses.saurashtrauniversity.edu/id/eprint/530

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“Studies In Heterocyclic Moieties”

A THESIS SUBMITTED TO THE SAURASHTRA UNIVERSITY

IN THE FACULTY OF SCIENCE

FOR THE DEGREE OF

Doctor of Philosophy

CHEMISTRY

BY ABHAY J. BAVISHI

UNDER THE GUIDANCE OF

PROF. ANAMIK SHAH

DEPARTMENT OF CHEMISTRY (DST-FIST FUNDED AND UGC-SAP SPONSORED) SAURASHTRA UNIVERSITY RAJKOT – 360 005 GUJARAT (INDIA)

June- 2011

Statement under O. Ph. D. 7 of Saurashtra University

The work included in the thesis is done by me under the supervision of

Prof. Anamik K. Shah and the contribution made thereof is my own

work.

Date:

Place: Abhay J. Bavishi

CERTIFICATE

This is to certify that the present work submitted for the Ph.D. degree of Saurashtra University by Mr. Abhay J. Bavishi has been the result of work carried out under my supervision and is a good contribution in the field of organic, heterocyclic and synthetic medicinal chemistry.

Date: Place: Prof. Anamik K. Shah Acknowledgement

It is a moment of gratification and pride to look back with a sense of contentment at the long traveled path, to be able to recapture some of the fine moments, to be able to think of the infinite number of people, some who were with me from the beginning, some who joined me at some stage during the journey, whose kindness, love and blessings has brought me to this day. I wish to thank each one of them from the bottom of my heart.

Therefore first and foremost I would like to bow my head with utter respect to my Parents who blessed me with their good wishes, relieving all types of stress and remaining always with me and continuing to boost my spirit. The never ending process of unsurpassable devotion, love and affection which showered upon me by my parents and my family who were ever boosting me to go ahead to reach the goal. However I assured them to be worthy of whatever they have done for me. I am gratified for their eternal love, trust and support. I bow my head humbly before All Mighty God for making me much capable that I could adopt and finish this task.

I would like to express my feelings of gratitude to Prof. P. H. Parsania, Professor and Head, Department of Chemistry, Saurashtra University, Rajkot for providing adequate infrastructure facilities.

I take this opportunity to express the deep sense of gratitude to my adored guide Prof. Anamik Shah, who supported my aspirations with lot of love and encouragement. I consider myself privilege to work under his generous guidance because I got the newer creative dimensions, thinking analyzing capacity and positive attitude, which has always helped me in making think simple and pragmatic too. I am always indebted to him.

I am very much grateful to Dr. Y.T.Naliapara for his valuable guidance during my entire work. I would like to convey my pleasant heartily thankfulness to my dearest friends Dr. Shailesh, Ashish (Master), Hardevsinh (Bapu), Dr. Shrey, Dhairya, Vipul, Kaushik, Bhavesh, Renish, Dr. Govind, Dr. Mahesh and Paresh for their time being help and moral support. I will never forget their all kind concern, help, best wishes and that they have done for me.

I am also thankful to my team members Manisha, Jignesh, Dr. Rakshit, Hitesh, Mrunal, Harshad, Vaibhav, Sachin, Dr. Nilay, Dr. Bharat, Ravi, Bhavin, Dilip, Pratik, Sabera, Vishwa, Madhvi and Hetal for creating most healthy working atmosphere.

I would also like to thank my seniors for all their help, and support during my research tenure. I heartily thank Dr. Dharmendra, Dr. Maitrey, Dr. Dhawal, Dr. Kuldip, Dr. Jitender, Dr. Priti, Dr. Atul, Dr. Jyoti, Dr. Jalpa, Dr. Vaibhav, Dr. Naval, Dr. Raju and Dr. Kena for their co-operation.

I was also blessed with some great colleagues whose presence has made this time a memorable time for me and my work in the laboratory was really enjoyable due to them. I thank Anil, Rakesh, Ashish, Amit, Ritesh, Piyush, Dipti, Lina, Suresh, Mehul, Rahul, Naimish, Vijay, Meenaxi, Pankaj, Piyush, Vipul, Jignesh, Pooja.

I am also thankful to Prof. V. H. Shah, Prof. S. H. Baluja., Prof. H. S. Joshi, Dr. M. K. Shah, Dr. U. C. Bhoya and Dr. R. C. Khunt.

I would also like to convey my pleasant regards and thankfulness towards, Kavita, Dr. Hitarth and Dr. Kena for their constant care, support and encouragement.

I would also like to express my deep sense of gratitude to Dr. Ranjanben A. Shah and Mr. Aditya A. Shah for their kind concern and moral support which made us feel at home. I specifically thank Ranjan madam for all her help and expertise that she gave me when I had met with a few accidents during this tenure.

I would also like to thank teaching and non-teaching staff members of Department of Chemistry, Saurashtra University, Rajkot.

I am also grateful to Sophisticated Analytical Instrumentation Facility (SAIF), RSIC, Punjab University, Chandigarh and CDRI, Lucknow and Alembic Research Centre, Alembic Ltd., for 1H NMR, and 13C NMR, Dept. of Chemistry, Saurashtra University, Rajkot for IR, Mass and Elemental analysis, TAACF, USA for providing facilities for carrying out biological activity, “National Facility For drug discovery through new chemical entities development and instrumentation support to small manufacturing pharma enterprises” for instrument support and limited financial assistance.

Lastly I would like to thank each and every one of them who helped me directly or indirectly during this wonderful and lots of experience gaining journey. I apologize if in any case I am missing out any of the names as I am thankful to one and all.

Abhay J. Bavishi

CONTENTS

GENERAL REMARKS

ABBREVIATIONS USED

Chapter -1 Synthesis of (5-chloro-2-methoxyphenyl)(5-alkyl-3-(substituted) (phenyl/alkyl)-1H- pyrazol-1-yl)methanones

1.1 Introduction 1 1.2 Literature review 1 1.3 Synthesis of functionalized pyrazoles using combinatorial chemistry approach 5 1.4 Pharmacological-significance of pyrazoles 8 1.5 Aim of current work 10 1.6 Reaction schemes 11 1.7 Plausible reaction mechanism 12 1.8 Experimental 13 1.9 Physical data 15 1.10 Spectral discussion 16 1.11 Analytical data 18 1.12 Results and discussion 23 1.13 Conclusion 23 1.14 Representative spectra 24 1.15 References 29

Chapter -2 Synthesis of 4-(3-(substituted)benzoyl-2-alkyl-5-(substituted) alkyl-4-(substituted)phenyl-1H-pyrrol-1-yl)-2H-chromene-2-ones

2.1 Introduction 32 2.2 Literature review 33 2.3 Pharmacology 42 2.4 Some drugs from pyrrole nucleus 42 2.5 Aim of current work 43 2.6 Reaction schemes 44 2.7 Plausible reaction mechanism 45 2.8 Experimental 46 2.9 Physical data 47 2.10 Spectral discussion 49 2.11 Analytical data 51 2.12 Results and discussion 60 2.13 Conclusion 60 2.14 Representative spectra 61 2.15 References 71

Chapter -3 Synthesis of 4-(dialkyl/alkyl)amino)-2-oxo-2H-chromene-3- carbonitirles

3.1 Introduction 76 3.2 Literature review 77 3.3 Pharmacology 86 3.4 Aim of current work 87 3.5 Reaction schemes 88 3.6 Plausible reaction mechanism 89 3.7 Experimental 90 3.8 Physical data 92 3.9 Spectral discussion 93 3.10 Analytical data 95 3.11 Results and discussion 99 3.12 Conclusion 99 3.13 Representative spectra 100 3.14 References 106

Chapter -4 Rapid synthesis of 5-(substituted)benzoyl-4-(1-phenyl, 3(substituted)phenyl-1H-pyrazole-4- yl)-2,6-dimethyl-1,4-dihydropyridine-3-carbonitriles

4.1 Introduction 111 4.2 Literature review 111 4.3 Pharmacology 117 4.4 Some drugs from 1,4-dihydropyridine nucleus 118 4.5 Pyrazoles : a versatile synthon 118 4.6 Aim of current work 121 4.7 Reaction schemes 122 4.8 Plausible reaction mechanism 123 4.9 Experimental 124 4.10 Physical data 126 4.11 Spectral discussion 127 4.12 Analytical data 129 4.13 Results and discussion 134 4.14 Conclusion 134 4.15 Representative spectra 135 4.16 References 140

Chapter-5 Synthesis of 8-((substituted)amino)-10-methylchromeno[3,4-b] thieno[2,3- e][1,4]diazepin-6(12H)-ones

5.1 Introduction 145 5.2 Literature review 146 5.3 Reported synthetic strategies for the piperazinyl derivetives of benzo- and 150 thienodiazepines 5.4 Pharmacology 157 5.5 Some drugs of diazepines 161 5.6 Aim of current work 162 5.7 Reaction schemes 163 5.8 Experimental 165 5.9 Physical data 168 5.10 Spectral discussion 169 5.11 Analytical data 171 5.12 Results and discussion 177 5.13 Conclusion 177 5.14 Representative spectra 178 5.15 References 187

BIOLOGICAL EVALUATION OF SYNTHESIZED COMPOUNDS SUMMARY CONFERENCES/SEMINARS/WORKSHOPS ATTENDED PUBLICATIONS

General Remarks

GENERAL REMARKS

1. Melting points were recorded by open capillary method and are uncorrected. 2. Infrared spectra were recorded on Shimadzu FT IR-8400 (Diffuse reflectance attachment) using KBr. Spectra were calibrated against the polystyrene absorption at 1610 cm-1. 3. 1H & 13C NMR spectra were recorded on Bruker Avance II 400 spectrometer.

Making a solution of samples in DMSO d6 and CDCl3 solvents using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned, and are given in the δ scale. The standard abbreviations s, d, t, q, m, dd, dt, br s refer to singlet, doublet, triplet, quartet, multiplet, doublet of a doublet, doublet of a triplet, AB quartet and broad singlet respectively. 4. Mass spectra were recorded on Shimadzu GC MS-QP 2010 spectrometer operating at 70 eV using direct injection probe technique. 5. Analytical thin layer chromatography (TLC) was performed on Merck

precoated silica gel-G F254 aluminium plates. Visualization of the spots on TLC plates was achieved either by exposure to iodine vapor or UV light. 6. The chemicals used for the synthesis of intermediates and end products were purchased from Spectrochem, Sisco Research Laboratories (SRL), Thomas Baker, Sd fine chemicals, Loba chemie and SU-Lab. 7. All the reactions were carried out in Samsung MW83Y Microwave Oven which was locally modified for carrying out chemical reactions 8. All evaporation of solvents was carried out under reduced pressure on Heidolph LABOROTA-400-efficient. 9. % Yield reported are isolated yields of material judged homogeneous by TLC and before recrystallization. 10. The structures and names of all compounds given in the experimental section and in physical data table were generated using ChemBio Draw Ultra 10.0. 11. Elemental analysis was carried out on Vario EL Carlo Erba 1108.

Department of Chemistry, Saurashtra University, Rajkot – 360 005

Abbreviations

ABBREVIATIONS

[bmim]BF4 1-butyl-3-methylimidazolium tetrafluoroborate [bmim]OH 1-Butyl-3-methylimidazolium hydroxide µm Micro meter AcOH Acetic Acid AIDS Acquired Immuno Deficiency Syndrome

AlCl3 Aluminum chloride Ar Aromatic

ArNHNH2 Phenyl Hydrazine ATP Adenosine triphosphate

BF3 Boron trifluoride

BiCl3 Bismuth chloride BP Boiling Point BuLi Butyllithium

CDCl3 Deuterated chloroform

CF3 Carbon trifluoride CNS Central Nervous System Conc. Concentrated

CS2 Carbon disulphide CuI Cuprous Iodide CuoAC Copper acetate DHP Dihydropyridine DIBAL Diisobutylaluminium hydride DMF Dimethyl Formamide DMSO Dimethyl Sulfoxide DNA Deoxyribonucleic acid EDDA ethylenediammonium diacetate EtoAc Ethyl acetate EtOH Ethanol EWG Electron Withdrawing Group

FeCl3 Iron(III) chloride FT-IR Fourier Transform Infrared GABA Gama-amino butyric acid GC -MS Gas Chromatography Mass Spectra

Hf(OTF)4 Hafnium trifluoromethanesulfonate HSAB Hard and soft (Lewis) acids and bases

IC50 Inhibitory Concentration IR Infra Red

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Abbreviations

K2CO3 Potassium Carbonate

K3PO4 Potassium Phosphate KBr Potassium Bromide

KMnO4 Potassium permanganate m Meta MAPK Mitogen-activated protein kinase MeOH Methanol MF Molecular Formula MHz Mega Hurtz MOM Methoxymethyl ether MP Melting Point mRNA Messenger Ribonucleic acid MS Mass Spectra MW Microwave MW Molecular Weight MWI Micro Wave Irradiation

Na2CO3 Sodium Carbonate

NaHCO3 Sodium Bicarbonate

NaHSO4 Sodium hydrogen sulphate NCEs New Chemical Entities

NEt3 N’tetramethyl ethylene diamine

NH2NH2H2O Hydrazine Hydrazide

NH4CN Ammonium Cyanide

NH4OAc4 Ammonium Acetate nm Nano meter NMR Nuclear Magnetic Resonance O Ortho

OEt2 Diethyl Ether P Para PAF anti platelet activating factor PBMC peripheral blood mononuclear cells

PCl5 Phosphorus pentachloride

Pd(OAc)4 Palladium tetraacetate

POCl3 Phosphorous Oxychloride PPO polyphenol oxidase p-TsOH Para Toluene Sulphonic Acid QSAR Quantitative Structural Activity Relationship R&D Research and development R.T. Room Temperature

Rf Retention Factor

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Abbreviations

Rh2(O2CC3F7)4 Rhodium (II) heptafluorobutryate tetramer RNA Ribo Nucleic Acid t-BuOH Potassium Tertiary Butyl Alcohol t-BuOK Potassium Tertiary Butoxide TEA Triethyl amine TFA Trifluoroaceitic acid THF Tetrahydrofuran

TiCl4 Titanium Tetrachloride TLC Thin Layer Chromatography TNFR Tumor necrosis factor R TNF-α Tumor necrosis factor ZnI Zinc Iodide 2

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CCCHHHAAAPPPTTTEEERRR---111

Synthesis of (5-chloro-2-methoxyphenyl)(5- alkyl-3-(substituted) (phenyl/alkyl)-1H- pyrazol-1-yl) methanones

Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.1 INRODUCTION

The chemistry of pyrazoles has been reviewed by Jarobe in 1967. Pyrazoles have attracted attention of medicinal chemists for both with regard to heterocyclic chemistry and the pharmacological activities associated with them. Pyrazole have been studied extensively because of ready accessibility, diverse chemical reactivity, broad spectrum of biological activity and varieties of industrial applications. Pyrazole has three possible tautomeric structures. But 2-pyrazole consist a unique class of nitrogen containing five member heterocycles.

As evident from the literature in recent years a significant portion of research work in heterocyclic chemistry has been devoted to pyrazoles containing different alkyl, aryl and heteroaryl groups as substituents.

1.2 LITERATURE REVIEW

Fluoride-mediated nucleophilic substitution reactions of 1-(4-methylsulfonyl (or sulfonamido)-2-pyridyl)-5-chloro-4- cyano pyrazoles with various amines and alcohols under mild conditions. The further reaction of novel pyrazoles provides the 5-alkyl amino and ether pyrazoles in moderate to high yields. 1

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

An efficient and divergent synthesis of fully substituted 1H-pyrazoles using

cyclopropyl oximes. Under Vilsmeier conditions (POCl3/DMF), substituted 1H- pyrazoles were synthesized from 1-carbamoyl, 1-oximyl cyclopropanes via sequential ring-opening, chlorovinylation, and intramolecular aza-cyclization. 2

A novel approach to the synthesis of pyrazole derivatives from tosylhydrazones of α,β-unsaturated carbonyl compounds possessing a β-hydrogen exploiting microwave (MW) activation coupled with solvent free reaction conditions. The cycloaddition was studied on three ketones (trans-4-phenyl-3-buten-2-one, β- ionone and trans-chalcone). The corresponding 3,5-disubstitued-1H-pyrazoles were obtained in high yields and after short reaction times. 3

The cyclization of isocyanide with the oxime or BOC-protected hydrazones of ethyl bromopyruvate furnished the pyrazole carboxy esters. 4

Regio-selective synthesis of 1,3,4,5-tetrasubstituted pyrazole derivatives from the reaction of Baylis-Hillman adducts of alkyl vinyl ketone and hydrazine derivatives. During the continuous studies on the chemical transformations of Baylis- Hillman adducts including the synthesis of pyrazole. 5

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

Highly efficient and regioselective synthesis of 1-aryl-3,4- substituted/annulated-5-(methylthio)-pyrazoles and 1-aryl-3-(methylthio)-4,5- substituted/ annulated pyrazoles via cyclocondensation of arylhydrazines with either α-oxoketene dithioacetals or α-oxodithioesters. 6

Synthesis of novel ketene N,S-acetals by the reaction of cyanoacetamide or cyanothioacetamide with phenylisothiocyanate in the presence of potassium hydroxide, followed by alkylation of the produced salts with methyl iodide. Further, the reaction of ketene N,S-acetals with hydrazine afforded different substituted pyrazoles in excellent yields. 7

Synthesid of 4-(3-phenylisoxazol-5-yl)morpholine derrivatives using ketene dithioacetals. The reaction of substituted acetophenones with carbon disulfide in the presence of base and followed by alkylation with methyl iodide afforded 4- phenoxyphenyl-2,2- bis(methylthio)vinyl ketones, which were further reacts with hydrazine hydrate to give substituted pyrazoles through in situ cyclization of the resulting N,S-acetals. 8

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

Reaction of fluorosubstituted cyanoacetamide derivatives with arylisothiocyanate in the presence of potassium hydroxide, yields novel fluorinated ketene N,S-acetals by the followed by the alkylation with methyl iodide. The reaction of fluorinated ketene N,S-acetals with hydrazine afforded different fluorosubstituted pyrazole derivatives in good yield. 9

Two general protocols for the reaction of electron-deficient N-arylhydrazones with nitroolefins allow a regioselective synthesis of 1,3,5-tri- and 1,3,4,5- tetrasubstituted pyrazoles. Studies on the stereochemistry of the key pyrazolidine intermediate suggest a stepwise cycloaddition mechanism.10

A series of 4-substituted 1H-pyrazole-5-carboxylates was prepared from the cyclocondensation reaction of unsymmetrical enaminodiketones with tert- butylhydrazine hydrochloride or carboxymethylhydrazine. The compounds were obtained regiospecifically and in very good yields.11

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

A general two-step synthesis of substituted 3-aminoindazoles from 2- bromobenzonitriles involves a palladium-catalyzed arylation of benzophenone hydrazone followed by an acidic deprotection/cyclization sequence. This procedure offers a general and efficient alternative to the typical SNAr reaction of hydrazine with o-fluorobenzonitriles. 12

1.3 SYNTHESIS OF FUNCTIONALIZED PYRAZOLES USING COMBINATORIAL CHEMISTRY APPROACH

In recent decades, combinatorial chemistry tools have enabled the rapid synthesis of a large number of heterocyclic small molecule libraries and it is recognized now as a key element of early drug discovery.13 The main advantage of the combinatorial technique is the speed at which diverse types of organic compounds can be synthesized, formulated, and tested for a particular application. Moreover, in combinatorial study the quantity of required material is less in comparison to conventional methods, which makes it more suitable when the materials are expensive.14

In 2009, Laborde E. et al15 have developed an efficient three-component, two- step “catch and release” solid-phase synthesis of 3,4,5-trisubstituted pyrazoles. The reaction involves a base-promoted condensation of a 2-sulfonyl acetonitrile derivative 1 with an isothiocyanate 2 and in situ immobilization of the resulting thiolate anion 3 on Merrifield resin. Reaction of the resin-bound sulfonyl intermediate 4 with hydrazine, followed by release from the resin and intramoleculer cyclization, afforded

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

3,5-diamino-4-(arylsulfonyl)-1H-pyrazoles 5. However, this methodology has some drawback such as; long reaction time, isolation of product and high reaction temperature.

O O 2 S CN Cl O O R1 R2-N=C=S THF, 60ºC S CN R2 R1 N S Et3N, THF, 25 °C H 1 3

O O O O NH2 S CN NH NH H O, S 2 2 2 R1 R1 NH R THF, 60-70 °C N 2 N S HN H R2

4 5

Recently, synthesis of structurally diverse and medicinally interesting series of 1, 4-dihydropyrano[2,3-c]pyrazoles via a three-component reaction using solution phase synthesis in excellent yields has been reported. 16

The parallel solution-phase approach for syntehsizing more than 2200 7- trifluoromethyl-substituted pyrazole[1,5-a]pyrimidine and 4,5,6,7- tetrahydropyrazolo[1,5-a]pyrimidine carboxamides on a 50-100-mg scale. The reactions were include assembly of the pyrazole[1,5-a]pyrimidine ring by condensation of 5-aminopyrazole derivatives with the corresponding trifluoromethyl- α-diketones. The libraries from libraries were then obtained in good yields and purities using solution-phase acylation and reduction methodologies. Simple manual techniques for parallel reactions using special CombiSyn synthesizers were coupled with easy purification procedures (crystallization from the reaction mixtures) to give high-purity final products. 17

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

A small combinatorial library had been synthesized containing pyrazolyl- pyrazoles and pyrazole[1,5-a]pyrimidines by traditional organic synthesis and parallel-liquid-phase combinatorial synthesis using α-S,S-acetal of ethyl cyanoacetate as key synthon and hydrazine hydrate. 18

A library of 4-(5-Iodo-3-Methylpyrazolyl)Phenyl- sulfonamide derivatives have been developed via solution-phase Suzuki coupling using Pd/C as a solid- supported catalyst. 19

O O NH2 O S NH O S 2

9steps N N I NH 2

Synthesis of substituted pyrazole through in situ generation of polymer-bound enaminones. The synthetic protocol makes use of commercially available aniline cellulose, a low-cost and versatile biopolymer, under very mild conditions. This new support allowed carrying out reactions in polar solvents under both conventional heating and MW irradiation without degradation of the polymer. The reaction between cellulose-bound enaminones and hydrazine to afford the target heterocycles in high yields directly in solution is the key step. The support can be conveniently recycled. 20

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

O O NH2 O S NH O S 2

9steps N N I NH 2

1.4 PHARMACOLOGICAL-SIGNIFICANCE OF PYRAZOLES

Pyrazoles belong to an important class of heterocycles due to their biological and pharmacological activities21,22 such as ¾ Anti-inflammatory,23 ¾ Herbicidal,24 ¾ Fungicidal,25 ¾ Bactericidal,26 ¾ Plant growth inhibitory,27 ¾ Antipyretic,28 ¾ Protein kinase inhibitory activities.29

Also, they are the key starting materials for the synthesis of commercial aryl/hetero-arylazopyrazolone dyes.30,31 Many other authors have reported other biological activities.31-57

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.4.1 SOME DRUGS FROM PYRAZOLES NUCLEUS 21-31

O COOH O N N N OH N (CH2)3N(CH3)2 Fezolamine N S N SH F Lonazolac N N N NH N Pyrazole meva lonolactone N OR Pyrazoline-4-dithiocarbamic acid E-3710

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.5 AIM OF CURRENT WORK

The structure of pyrazoles are of prime important in the Medicinal Chemistry research as various drug molecules possess pyrazoles as the core moiety, exhibiting pharmacological activities like anti-inflammatory, herbicidal, fungicidal, bactericidal, plant growth inhibitory, antipyretic, etc Thus, the opportunity to synthesize some new pyrazole entities possessing chloro, and methoxy group in the benzene ring and to explore their biological activity was the main rational behind initializing the work included in this chapter as the presence of chloro and methoxy group may enhance the activity of newly synthesized pyrazoles.

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.6 REACTION SCHEMES

1.6.1 PREPARATION OF BENZOYL ACETONES :

Reagents / Reaction Condition (a): Ethyl Acetate, C2H5ONa/ 0-5°C, 2 hours

1.6.2 PREPARATION OF ACETOACETANILIDE :

Reagents / Reaction Condition (b): Ethyl Aceto Acetate, MW 300W, 25-30 mins.

1.6.3 PREPARATION OF (5-CHLORO-2-METHOXYPHENYL)(5-ALKYL-3- (SUBSTITUTED) (PHENYL/ALKYL)-1H-PYRAZOL-1- YL)METHANONES :

STEP-I

CH3 NH2 O O O NH

O c O CH3 CH3

Cl Cl

Reagents / Reaction Condition (c): Hydrazine Hydrate (99%), MW 300W, 2 min

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

STEP-II

Reagents / Reaction Condition (d): Ethanol, Con. HCl, reflux, 10 h

1.7 PLAUSIBLE REACTION MECHANISM

R1 .. R2 OH HO R1 OH O O O .. O NH NH NH R R .. R R N 2 1 2 HN 2 N H R O R O

H .. HO R1 OH R1 H2O R1 HO R1 2 .. N NH R N N R 2 N R2 N R2 N 2 N

O R O R R O R O

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.8 EXPERIMENTAL

1.8.1 MATERIALS AND METHODS Melting points were determined in open capillary tubes and are uncorrected. Formation of the compounds was routinely checked by TLC on silica gel-G plates of 0.5 mm thickness and spots were located by iodine and UV. Formation of all compounds was purified by using column chromatography. IR spectra were recorded in Shimadzu FT-IR-8400 instrument using KBr method. Mass spectra were recorded on Shimadzu GC-MS-QP-2010 model using Direct Injection Probe 1H technique. NMR was determined in CDCl3/DMSO solution on a Bruker Ac 300 MHz spectrometer.

1.8.2 PREPARATION OF BENZOYL ACETONES :

A mixture of sodium ethoxide (0.2 mol), ethyl acetate (0.2 mol) were taken in 250 ml RBF then slowely add (0.05 mol) of aceto phenone to the mixture below 5°C. After addition of acetophenone to it allow it for one day in freeze and pour it to ice water mixture. Then acidify it by glacial acetic acid to get product. After that filter the product and wash with chilled water to remove acidity and dry it.

1.8.3 PREPARATION OF ACETOACETANILIDES :

A mixture of amine (1 mmol) and ethyl acetoacetate (2.5-3.0 mmol) was taken in a R.B.F. and placed in microwave oven and irradiated at 600W for 5-50 minutes. The reaction was monitored by TLC. After the completion of reaction, product was washed with petroleum ether (60-80°C) and the corresponding acetoacetylated products were separated by filtration in 70-97% yield.

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.8.4 PREPARATION OF (5-CHLORO-2-METHOXYPHENYL)(5-ALKYL-3- (SUBSTITUTED)(PHENYL/ALKYL)-1H-PYRAZOL-1-YL) METHANONES :

STEP-I Mixture of methyl-5-chloro-2-methoxy benzoate (0.01 mol) and hydrazine hydrate (0.02 mol) was irradiated under microwave irradiation for 2 min at 300W. After the completion of the reaction solid precipitates out, filtered and washed with water to yield 91% product. M.P. 162°C.

STEP-II

Methyl 5-chloro-2-methoxybenzoate (0.01 mol), α-diketo compound (0.01 mol) was allowed to reflux for 10 h using ethanol (10 mL) as a solvent in presence of catalytic amount of conc. HCl. Product precipitates out as a crystalline solid was confirmed by TLC further washed with water and dried to yield desired compounds.

The physical constants of newly synthesized compounds are given in Table No.1

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.9 PHYSICAL DATA

Physical data of (5-chloro-2-methoxyphenyl) (5-alkyl-3-(substituted) (phenyl/ alkyl)-1H-pyrazol-1-yl)methanones.

TABLE - 1

Sr. No. Code R1 R2 M.P. Rf 1 BAJ-401 CH3 C6H5 180-182 0.46 2 BAJ-402 CH3 4-F-C6H4 204-206 0.52 3 BAJ-403 CH3 2,4-di-Cl- C6H3 226-228 0.44 4 BAJ-404 CH3 NH-2,4-di-Me- C6H3 208-210 0.48 5 BAJ-405 CH3 NH-3-OMe-C6H4 196-198 0.50 6 BAJ-406 CH3 NH-4-Cl-C6H4 188-190 0.40 7 BAJ-407 CH3 NH-3-Cl-C6H4 210-212 0.44 8 BAJ-408 CH3 NH-3-F-C6H4 178-180 0.48 9 BAJ-409 CH3 NH-4-Br-C6H4 186-188 0.42 10 BAJ-410 CH3 NH-2-pyridyl 168-170 0.46 11 BAJ-411 CH3 NH-3-pyridyl 194-196 0.42 12 BAJ-412 CH3 CH3 206-208 0.54 13 BAJ-413 CH2-Cl O-CH2-CH3 178-180 0.50 14 BAJ-414 CH3 O-CH2-CH(CH3)2 166-168 0.48 15 BAJ-415 CH3 O-CH(CH3)2 218-220 0.40 16 BAJ-416 CH3 O-CH2-CH3 208-210 0.46 17 BAJ-417 CH3 O-CH3 178-180 0.44

Rf value was determined using solvent system = Ethyl Acetate : Hexane (2 : 3)

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1.10 SPECTRAL DISCUSSION

1.10.1 IR SPECTRA

IR spectra of the synthesized compounds were recorded on Shimadzu FT-IR 8400 model using KBr method. Various functional groups present were identified by characteristic frequency obtained for them. The characteristic bands of (-C=N-) were obtained for stretching at 1650-1600 cm-1. The stretching vibrations (–C-O-C-) group showed in the finger print region of 1100-1050 cm-1 while (-C-Cl-) stretching signal was obtained at 800-750 cm-1. It gives aromatic (-C-H-) stretching frequencies between 3200-3000 cm-1 and ring skeleton (-C=C-) stretching at 1500-1350 cm-1 C-H stretching frequencies for methyl and methylene group were obtained near 2950 - 2850 cm-1.

1.10.2 MASS SPECTRA

1.10.3 1H NMR SPECTRA

1H NMR spectra of the synthesized compounds were recorded on Bruker

Avance II 300 spectrometer by making a solution of samples in DMSO-d6 solvent using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned. Numbers of protons and carbons identified from NMR spectrum and their chemical shift (δ ppm) were in the agreement of the structure of the molecule. J values were calculated to identify o, m and p coupling. In some cases, aromatic protons were obtained as multiplet. Interpretation of representative spectra is discussed further in this chapter.

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.10.4 13C NMR SPECTRA

13C NMR spectra of the synthesized compounds were recorded on Bruker

Avance II 300 spectrometer by making a solution of samples in DMSO-d6 solvent using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned. Types of carbons identified from NMR spectrum and their chemical shift (δ ppm) were in the agreement of the structure of the molecule. Aliphatic carbon was observed between 15-25, while methoxy carbon was observed between 55-60 δ ppm, aromatic carbon was observed between 115-140 δ ppm, keto carbon was observed between 160-165 δ ppm.

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1.11 ANALYTICAL DATA

(5-Chloro-2-methoxyphenyl)(5-methyl-3-phenyl-1H-pyrazol-1-yl)methanone (BAJ-401) Yield: 72%, IR (KBr, cm-1): 3070(aromatic -C-H stretching), 2987, 2943(aliphatic - C-H stretching), 1670(-C=O stretching), 1635(-C=N stretching), 1535, 1481(Aromatic -C-C- stretching), 1184(-C-N stretching), 1109(-C-O-C- stretching), 1H 806(C-Cl stretching), 694(-C-H oop bending disubstitued), NMR (DMSO-d6) δ ppm: 3H, s (2.14), 3H, s (3.87), 1H, d (7.23-7.26, J=9.0 Hz), 5H, m (7.57-7.72), 1H, s (7.84), 1H. dd (8.05-8.08), 1H, d (8.28-8.31, J=9.0Hz), 13C: 22.12, 57.34, 90.45, 123.94, 124.92, 125.87, 126.20, 127.08, 127.92, 129.46, 130.93, 131.27, 131.72, 133.52, 134.37, 152.97, 157.71. MS m/z = 326 (M+), 328 (M+2); % Anal. Calcd. for

C18H15ClN2O2: C, 66.16; H, 4.63; Cl, 10.85; N, 8.57; O, 9.79.

(5-Chloro-2-methoxyphenyl)(3-(4-fluorophenyl)-5-methyl-1H-pyrazol-1- yl)methanone (BAJ-402) Yield: 75%, IR (KBr, cm-1): 3059(aromatic -C-H stretching), 2941(aliphatic –C-H stretching), 1695 (-C=O stretching), 1637 (-C=N stretching), 1546 (aromatic -C-C- stretching), 1184 (-C-N stretching), 1109(-C-O-C- stretching), 1049(-C-F stretching), 758(-C-Cl stretching), 725 (disubstituted), 688(monosubstituted); MS m/z = 344 (M+), +2 346 (M ); % Anal. Calcd. for C18H14ClFN2O2: C, 62.71; H, 4.09; Cl, 10.28; F, 5.51; N, 8.13; O, 9.28.

(5-Chloro-2-methoxyphenyl)(3-(2,4-dichlorophenyl)-5-methyl-1H-pyrazol-1- yl)methanone (BAJ-403) Yield: 70%, IR (KBr, cm-1): 3032(aromatic -C-H stretching), 2935(aliphatic –C-H stretching), 1697 (-C=O stretching), 1600(-C=N stretching), 1518(aromatic -C-C- stretching), 1184(-C-N tretching), 1109(-C-O-C- stretching), 801(-C-Cl stretching), 748(disubstituted), 701 (monosubstituted),; MS m/z = 395 (M+), 397 (M+2); % Anal.

Calcd. for C18H13Cl3N2O2: C, 54.64; H, 3.31; Cl, 26.88; N, 7.08; O, 8.09.

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(5-Chloro-2-methoxyphenyl)(3-((2,4-dimethylphenyl)amino)-5-methyl-1H- pyrazol-1-yl)methanone(BAJ-404) Yield: 74%, IR (KBr, cm-1): 3416(-N-H stretching), 3044(aromatic -C-H stretching), 2922 (aliphatic –CH- stretching), 1690(-C=O stretching), 1666-1599(-N-H bending), 1638(-C=N stretching), 1543(Aromatic -C-C- stretching), 1180 (-C-N stretching), 1112(-C-O-C- stretching), 782(-C-Cl stretching)754 (disubstituted),; MS m/z = 369 + +2 (M ), 371 (M ); % Anal. Calcd. for C20H20ClN3O2: C, 64.95; H, 5.45; Cl, 9.59; N, 11.36; O, 8.65.

(5-Chloro-2-methoxyphenyl)(3-((3-methoxyphenyl)amino)-5-methyl-1H-pyrazol- 1-yl)methanone (BAJ-405) Yield: 72%, IR (KBr, cm-1): 3416(-N-H stretching), 3055(aromatic -C-H stretching), 2922 (aliphatic –C-H stretching), 1694(-C=O stretching), 1683(N-H bending), 1646 (- C=N stretching), 1540(aromatic -C-C- stretching), 1188(-C-N stretching), 1114 (-C- O-C- stretching), 784(-C-Cl stretching), 751 (disubstituted)701 (monosubstituted),; + +2 MS m/z = 371 (M ), 373 (M ); % Anal. Calcd. for C19H18ClN3O3: C, 61.38; H, 4.88; Cl, 9.54; N, 11.30; O, 12.91.

(5-Chloro-2-methoxyphenyl)(3-((4-chlorophenyl)amino)-5-methyl-1H-pyrazol-1- yl)methanone(BAJ-406) Yield: 78%, IR (KBr, cm-1): 3446(-N-H stretching), 3062(aromatic -C-H stretching), 2926 (aliphatic –C-H str.), 1688(-C=O stretching), 1666(-N-H bending),1641(-C=N stretching), 1547 (aromatic -C-C- stretching), 1182(-C-N stretching), 1104(-C-O-C- stretching), 778(-C-Cl stretching); 751 (disubstituted), 705 (mono substituted), MS + +2 m/z = 376 (M ), 378 (M ); % Anal. Calcd. for C18H15Cl2N3O2: C, 57.46; H, 4.02; Cl, 18.85; N, 11.17; O, 8.50.

(5-Chloro-2-methoxyphenyl)(3-((3-chlorophenyl)amino)-5-methyl-1H-pyrazol-1- yl)methanone(BAJ-407) Yield: 70%, IR (KBr, cm-1): 3196(-N-H stretching), 3018(aromatic -C-H stretching), 2945(aliphatic –C-H stretching), 1718(-C=O stretching), 1668(-N-H bending), 1606(- C=N stretching), 1546, 1483(Aromatic -C-C- stretching), 1126(-C-N stretching), 1072(-C-O-C- stretching), 783(-C-Cl stretching), 769(disubstituted), 675(mono

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1H substituted), NMR (DMSO-d6) δ ppm: 3H, s (2.02), 3H, s (3.45), 1H, s (6.93), 1H, m (7.10-7.13), 1H, d (7.22-7.25, 9.0Hz), 1H, t (7.31-7.37), 1H, d (7.44-7.47, 9.0 Hz), 1H, dd (7.55-7.59), 1H, d (7.73-7.74, 3.0 Hz), 1H, s (7.83), 1H, s (10.44), 13C: 17.46, 57.62, 90.52, 115.22, 118.42, 119.52, 123.94, 124.77, 125.56, 130.57, 131.33, 132.87, 133.94, 141.26, 156.68, 160.95. MS m/z = 376 (M+), 378 (M+2); % Anal. Calcd. for

C18H15Cl2N3O2: C, 57.46; H, 4.02; Cl, 18.85; N, 11.17; O, 8.50.

(5-Chloro-2-methoxyphenyl)(3-((4-fluorophenyl)amino)-5-methyl-1H-pyrazol-1- yl)methanone(BAJ-408) Yield: 76%, IR (KBr, cm-1): 3491(-N-H stretching), 3052(aromatic -C-H stretching), 2928 (aliphatic –C-H stretching), 1692(-C=O stretching), 1674(-N-H bending), 1648(- C=N stretching), 1539(aromatic -C-C- stretching), 1184(-C-N stretching), 1112(-C-O- C- stretching), 1091(C-F stretching), 763(-C-Cl stretching), 751 (disubstituted), 708 (mono substituted),; MS m/z = 359 (M+), 361 (M+2); % Anal. Calcd. for

C18H15ClFN3O2: C, 60.09; H, 4.20; Cl, 9.85; F, 5.28; N, 11.68; O, 8.89.

(3-((4-Bromophenyl)amino)-5-methyl-1H-pyrazol-1-yl)(5-chloro-2- methoxyphenyl) methanone (BAJ-409) Yield: 70%, IR (KBr, cm-1): 3296(-N-H stretching), 3064(aromatic -C-H stretching), 2962(aliphatic –C-H stretching), 1695(-C=O stretching), 1672 (-N-H bending), 1641(- C=N stretching), 1548(aromatic -C-C- stretching), 1186 (-C-N stretching), 1114 (-C- O-C- stretching), 776 (-C-Cl stretching), 752(disubstituted), 686(monosubstituted), 579(C-Br stretching),; MS m/z = 420 (M+), 422 (M+2); % Anal. Calcd. for

C18H15BrClN3O2: C, 51.39; H, 3.59; Br, 18.99; Cl, 8.43; N, 9.99; O, 7.61.

(5-Chloro-2-methoxyphenyl)(5-methyl-3-(pyridin-2-ylamino)-1H-pyrazol-1- yl)methanone (BAJ-410) Yield: 76%, IR (KBr, cm-1): 3290(-N-H stretching), 3061(aromatic -C-H stretching), 2924(aliphatic –C-H stretching), 1691(-C=O stretching), 1669(-N-H bending), 1643(- C=N stretching), 1550(aromatic -C-C- stretching), 1180(-C-N stretching), 1116(-C-O- C- stretching), 774 (-C-Cl stretching), 754(disubstituted), ; MS m/z = 342 (M+), 344 +2 (M ); % Anal. Calcd. for C17H15ClN4O2: C, 59.57; H, 4.41; Cl, 10.34; N, 16.34; O, 9.34.

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

(5-Chloro-2-methoxyphenyl)(5-methyl-3-(pyridin-3-ylamino)-1H-pyrazol-1- yl)methanone (BAJ-411) Yield: 68%, IR (KBr, cm-1): 3286(-N-H stretching), 3052(aromatic -C-H stretching), 2921 (aliphatic -C-H stretching), 1691(-C=O stretching), 1664(-N-H bending), 1646(- C=N stretching), 1547(aromatic -C-C- stretching), 1181(-C-N stretching), 1109(-C-O- C- stretching), 768 (-C-Cl stretching), 756 (disubstituted), ; MS m/z = 342 (M+), 344 +2 (M ) ; % Anal. Calcd. for C17H15ClN4O2: C, 59.57; H, 4.41; Cl, 10.34; N, 16.34; O, 9.34.

(5-Chloro-2-methoxyphenyl)(3,5-dimethyl-1H-pyrazol-1-yl)methanone(BAJ-412) Yield: 74%, IR (KBr, cm-1): 3050(aromatic -C-H stretching), 2930(aliphatic –C-H stretching), 1688(-C=O stretching), 1640(-C=N stretching), 1546(aromatic -C-C- stretching), 1181(-C-N stretching), 1115(-C-O-C- stretching), 765(-C-Cl stretching), 751(disubstituted) ; MS m/z = 264 (M+), 266 (M+2); % Anal. Calcd. for

C13H13ClN2O2: C, 58.99; H, 4.95; Cl, 13.39; N, 10.58; O, 12.09.

(5-Chloro-2-methoxyphenyl)(5-(chloromethyl)-3-ethoxy-1H-pyrazol-1- yl)methanone (BAJ-413) Yield: 70%, IR (KBr, cm-1): 3064(aromatic -C-H stretching), 2926 (aliphatic –C-H str.), 2891(-C-H stretching tertiary), 2857(aliphatic -CH2 stretching),1696 (-C=O stretching), 1641 (-C=N stretching), 1540(aromatic -C-C- stretching), 1509,1455, 1366(CH bending), 1186 (-C-N stretching), 1109(-C-O-C- stretching), 762 (-C-Cl stretching), 753(disubstituted); MS m/z = 329 (M+), 331 (M+2); % Anal. Calcd. for

C14H14Cl2N2O3: C, 51.08; H, 4.29; Cl, 21.54; N, 8.51; O, 14.58.

(5-Chloro-2-methoxyphenyl)(3-isobutoxy-5-methyl-1H-pyrazol-1-yl)methanone (BAJ-414) Yield: 72%, IR (KBr, cm-1): 3063(aromatic -C-H stretching), 2928(aliphatic –C-H stretching), 2889(-C-H stretching tertiary), 2843(aliphatic -CH2- stretching), 1694(- C=O stretching), 1638(-C=N stretching), 1541(aromatic -C-C- stretching), 1518,1445,1354 (C-H bending), 1182 (-C-N stretching), 1109(-C-O-C- stretching), 761(-C-Cl stretching), 755(disubstituted); MS m/z = 322 (M+), 324 (M+2); % Anal.

Calcd. for C16H19ClN2O3: C, 59.54; H, 5.93; Cl, 10.98; N, 8.68; O, 14.87.

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

(5-Chloro-2-methoxyphenyl)(3-isopropoxy-5-methyl-1H-pyrazol-1-yl)methanone (BAJ-415) Yield: 78%, IR (KBr, cm-1): 3061(aromatic -C-H stretching), 2925(aliphatic –C-H stretching), 2899(-C-H stretching tertiary), 2828(aliphatic -CH2 stretching), 1696(- C=O stretching), 1648(-C=N stretching), 1551(aromatic -C-C- stretching), 1529,1435,1343(C-H bending), 1180(-C-N stretching), 1113(-C-O-C- stretching), 770 (-C-Cl stretching), 759(disubstituted); MS m/z = 308 (M+), 310 (M+2); % Anal.

Calcd. for C15H17ClN2O3: C, 58.35; H, 5.55; Cl, 11.48; N, 9.07; O, 15.55.

(5-Chloro-2-methoxyphenyl)(3-ethoxy-5-methyl-1H-pyrazol-1-yl)methanone (BAJ-416) Yield: 68%, IR (KBr, cm-1): 3048(aromatic -C-H stretching), 2927(Aliphatic –C-H

stretching), 2836 (Aliphatic -CH2 stretching), 1695(-C=O stretching), 1650(-C=N stretching), 1541(aromatic -C-C- stretching), 1190(-C-N stretching), 1458, 1356 (-C- H bending), 1115(-C-O-C- stretching), 766 (-C-Cl stretching), 753(disubstituted); + +2 MS m/z = 294(M ), 296 (M ); % Anal. Calcd. for C14H15ClN2O3: C, 57.05; H, 5.13; Cl, 12.03; N, 9.50; O, 16.29.

(5-Chloro-2-methoxyphenyl)(3-methoxy-5-methyl-1H-pyrazol-1-yl)methanone (BAJ-417) Yield: 72%, IR (KBr, cm-1): 3051(aaromatic -C-H stretching), 2927(aliphatic –C-H stretching), 1694(-C=O stretching), 1648(-C=N stretching), 1536(aromatic -C-C- stretching), 1186(-C-N stretching), 1109(-C-O-C- stretching), 767(-C-Cl stretching), + +2 754(disubsituted); MS m/z = 280 (M ), 282 (M ); % Anal. Calcd. for C13H13ClN2O3: C, 55.62; H, 4.67; Cl, 12.63; N, 9.98; O, 17.10.

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.12 RESULTS AND DISCUSSION

Synthesis of substituted pyrazole has been carried out by the reaction of 5- chloro-2-methoxybenzohydrazide and different α-diketo compounds. Total 17 comounds were synthesized and characterized using spectroscopic technique. Synthesized compounds were explored by performing various biological activities.

1.13 CONCLUSION

Pyrazole derivatives of 5-chloro-2-methoxybenzohydrazide were prepared. Presence of electron withdrawing groups in the core structure augment activities of pyrazole moiety. The reaction was carried out using ethanol as solvent and catalytic amount of Conc. HCl. The significance of present process is good yield and easy work up method. The synthesized compounds were further explored for biological screening.

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.14 REPREENTATIVE SPECTRA

1.14.1 IR Spectrum of BAJ-401

1.14.2 MASS Spectrum of BAJ-401

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.14.3 1H NMR Spectrum of BAJ-401

1.14.4 Expanded 1H NMR Spectrum of BAJ-401

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.14.5 13C NMR Spectrum of BAJ-401

1.14.6 IR Spectrum of BAJ-407

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.14.7 MASS Spectrum of BAJ-407

1.14.8 1H NMR Spectrum of BAJ-407

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Chapter – 1 Synthesis of 1H-pyrazole derivatives

1.14.9 Expanded 1H NMR Spectrum of BAJ-407

1.14.10 13C NMR Spectrum of BAJ-407

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1.15 REFERENCES

1. Shavnya, A., Sakya, S. M., Minich, M. L., Rast, B., DeMello, K. L., Jaynes B. H.; Tet. Lett., 2005, 46, 6887. 2. Wang, K., Xiang, D., Liu, J., Pan, W., Dong, D.; Org. Lett., 2008, 10, 1691. 3. Corradi, A., Leonelli, C., Rizzuti, A., Rosa, R., Veronesi, P., Grandi, R., Baldassari, S., Villa, C.; Molecules, 2007, 12, 1482. 4. Wang, X., Xu, F., Xu, Q., Mahmud, H., Houze, J., Zhu, L., Akerman, M., Tonn, G., Tang, L.; Bioorg. Med. Chem. Lett., 2006, 16, 2800. 5. Kim, H. S., Kim, J. N.; Bull. Korean Chem. Soc., 2007, 28, 1841. 6. Peruncheralathan, S., Khan, T. A., Ila, H., Junjappa, H.; J. Org. Chem., 2005, 70, 10030. 7. Elgemeie, G. H., Elghandour, A. H., Elaziz, G. W.; Synth. Comm., 2007, 37, 2827. 8. Kuettel, S., Zambon, A., Kaiser, M., Brun, R., Scapozza, L., Perozzo, R.; J. Med. Chem. 2007, 50, 5833. 9. Kurz, T., Widyan, K., Elgemeie, G. H.; Phosphorus Sulfur and Silicon, 2006, 181, 299. 10. Deng, X., Mani, N. S; J. Org. Chem., 2008, 73, 2412. 11. Rosa, F. A., Machado, P., Vargas, P. S., Bonacorso, H. G., Zanatta, N., Martins, M. A. P.; Synlett, 2008, 1673. 12. Lefebvre, V., Cailly, T., Fabis, F., Rault, S.; J. Org. Chem., 2010, 75, 2730. 13. (a) Thompson, L. A., Ellman, J. A.; Chem. Rev., 1996, 96, 555. (b) Booth, S., Hermkens, P. H. H., Ottenheijm, H. C. J., Rees, D. C.; Tetrahedron, 1998, 54, 15385. 14. (a) Devlin, J. P., High Throughput Screening: The Discovery of Bioactive Substances; Marcel Dekker: New York, 1997. (b) Gordon, E. M., Kerwin, J. F., Jr.; Combinatorial Chemistry and Molecular Diversity in Drug Discovery; Wiley: New York, 1998. 15. Wenli, M., Peterson, B., Kelson, A., Laborde, E.; J. Comb. Chem., 2009, 11, 697. 16. Lehmann, F., Holm, M., Laufer, S.; J. Comb. Chem., 2008, 10, 364.

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17. Dalinger, I. L., Vatsadse, I. A., Shevelev, S. A., Ivachtchenko, A. V.; J. Comb. Chem., 2005, 7, 236. 18. Rena, X. L., Lib, H. B., Wub, C., Yang, H. Z.; Arkivoc, 2005, 15, 59. 19. Organ, M. G., Mayer, S.; J. Comb. Chem. 2003, 5, 118. 20. Luca, L. D., Giacomelli, G., Porcheddu, A., Salaris, M., Taddei, M.; J. Comb. Chem., 2003, 5, 465. 21. Scheibye, S., El-Barbary, A. A., Lawesson, S. O.; Tetrahedron, 1982, 38, 3753. 22. Weissberger, A., Wiley, R. H., Wiley, P.; "The Chemistry of Heterocyclic Compounds: Pyrazolinones, Pyrazolidones and Derivatives," John Wiley (Ed.), New York, 1964. 23. Hiremith, S. P., Rudresh, K., Saundan, A. R. I.; Indian J. Chem., 2002, 41B, 394. 24. Joerg, S., Reinhold, G., Otto, S., Joachim, S. H., Robert, S., Klaus, L.; Ger. Offen.; DE 3, 625, 686; Chem. Abstr., 1988, 108, 167, 465. 25. Dhal, P. N., Achary, T. E., Nayak, A.; J. Indian Chem. Soc., 1975, 52, 1196. 26. Souza, F. R., Souza, V. T., Ratzlaff, V., Borges, L. P., Oliveira, M. R., Bonacorso, H. G., Zanatta, N., Martins, M. A. P., Mello, C. F.; Eur. J. Pharm., 2002, 451, 141. 27. WO2001032653. 28. Karci, F., Ertan, N.; Dyes and Pigments, 2002, 55, 99. 29. Ho, Y. W.; Dyes Pigments, 2005, 64, 223. 30. Patel, H. V., Vyas, K. A., Fernandes, P. S.; Indian J. Chem., 1990, 29B, 966. 31. Rao, M. N. A., Satyanarayana, K.; Eur. J. Med. Chem., 1995, 30, 641. 32. Menozzi, G., Colla, P. L., Merello, L., Fossa, P.; Bioorg. Med. Chem., 2004, 12, 5465. 33. Palaska, E., Erol, D., Demirdamar, R.; Eur. J. Med. Chem., 1996, 31, 43. 34. Ming, L., Hua-Zheng, Y., Wei-Jun, F.; Chin. J. Chem., 2004, 22, 1064. 35. Singh, S. P., Aggarwal, R., Tyagi, P.; Eur. J. Med. Chem., 2005, 40, 922. 36. Patel, H. V., Vyas, K. A., Fernandes, P. S.; Indian J. Chem., 1990, 29B, 1044. 37. Azarifar, D., Shaebanzadeh, M.; Molecules, 2002, 7, 885. 38. Kuo, S. C., Wang, J. P., Nakamura, H.; Chem. Pharm. Bull., 1994, 42, 2036. 39. Upadhyay, T. M., Barot, V. M.; Indian J. Heterocycl. Chem., 2006, 15, 393.

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40. Joshi, H. S., Chovatia, P. T., Kachhadia, P. K.; J. Serb. Chem. Soc., 2007, 71, 713. 41. Badawey, E. A. M., El-Hawash, S. A. M.; Eur. J. Med. Chem., 2006, 41, 155. 42. Daidone, G., Maggio, B., Plescia, S., Raffa, D.; Eur. J. Med. Chem., 1998, 33, 375. 43. Saleh, M. A., Abdel-Megeed, M. F., Abdo, M. A.; Molecules, 2003, 8, 363. 44. Kunick, C., Kohfeld, S., Jones, P. G.; Eur. J. Med. Chem., 2007, 42, 1317. 45. Bruni, F., Selleri, S., Costanzo, A.; Eur. J. Med. Chem., 1997, 32, 941. 46. Saczewski, F., Brzozowski, Z.; Eur. J. Med. Chem., 2002, 37, 709. 47. Banoglu, E., Sukuroglu, M., Nacak Baytas, S.; Turk J. Chem., 2007, 31, 677. 48. Karthikeyan, M. S., Holla, B. S., Kumari, N. S.; Eur. J. Med. Chem., 2007, 42, 30. 49. Bekhit, A. A., Baraka, A. M., Rostom, S. A. F.; Eur. J. Med. Chem., 2003, 38, 27. 50. Brana, M. F., Gradillas, A., Lopez, B.; Bioorg. Med. Chem., 2006, 14, 9. 51. Gupta, U., Sareen, V.; Indian J. Heterocycl. Chem., 2004, 13, 351. 52. Rostom, S. A. F., Shalaby, M. A.; Eur. J. Med. Chem., 2003, 38, 959. 53. Daidone, G., Maggio, B., Caruso, A.; Eur. J. Med. Chem., 2001, 36, 737. 54. Metwally, M. A., EI-Kerdawy, M., Ismaiel, A. M.; Indian J. Chem., 1986, 25B, 1238. 55. Akbas, E., Berber, I.; Eur. J. Med. Chem., 2005, 40, 401. 56. Om Prakash, Parkash, V., Kumar, R.; Eur. J. Med. Chem., 2008, 43, 435. 57. Bekhit, A. A., Abdel Ghany, Y. S., Baraka, A.; Eur. J. Med. Chem., 2008, 43, 456.

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Synthesis of 4-(3-(substituted)benzoyl-2- alkyl-5-(substituted)alkyl-4- (substituted)phenyl-1H-pyrrol-1-yl)-2H- chromene-2-ones

Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.1 INTRODUCTION

Pyrrole is an important π-excessive aromatic heterocycle because this ring system is incorporated in as a basic structural unit in porphyrins;porphin (heam) and chlorin(chlorophyll) and corrins (vitamin B12). More over the presence of pyrrole ring in system in porphobilinogen (intermediate in biosynthesis of porphyrins and vitamin B12), biliverdin and bilirubin(pyrrole-based bile pigments) and pyrrolnitrin(with antibiotic activity) has provided an impetus to the pyrrole chemistry.

Pyrrole has a planar pentagonal structure with four carbon atoms and nitrogen sp2-hybridized. Each ring atom forms two sp2-sp2 σ -bonds to its neighbouring ring atoms and one sp2-sσ -bond to a hydrogen atom. The remaining unhybridized p- orbitals, one on each ring atom(with one electron on each carbon and two electron on nitrogen), are perpendicular to the plane of σ -bondsand overlap to form a π-molecular system with three bonding orbitals. The six π-electrons form an aromatic sextet which is responsible for aromaticity and renders stability to the pyrrole ring. The Cα-N and

Cα-Cβ bonds are shroter than normal single bonds, where as Cα-Cβ bonds are normal

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than normal double bonds. The molecular dimentions of the pyrrole reflect cyclic delocalization with the environment of lone pair of electrons on the nitrogen atom. Pyrrole is extremely weak base because the lone pair of electrons on the nitrogen atom involved in the cyclic delocalization and is, therefore, less available for protonation. Moreover, pyrrole is a weaker base than pyridine and even than aniline in which lone pair on the nitrogen atom is involved in the resonance and not essentially

contributes to the aromatic sexlet. The protonation of pyrrole at nitrogen or C2 or C3 atom of the ring reduces its basicity and destroys its aromaticity. However, C- and N- alkyl substituents enhance the basicity of pyrrole but the electron withdrawing substituents on the ring make pyrrole a weaker base. 1-11

2.2 LITERATURE REVIEW

Pyrroles are generally synthesized by the cyclization reactions involving nucleophilic-electrophilic interactions. This is the most widely used method and involves the cyclizative condensation of α-aminoketones or α-amino-β-keto esters(three atom fragment with nucleophilic nitrogen and electrophilic carbonyl carbon) with β-diketones or β-ketoesters (two atom fragment with electrophilic

carbonyl carbon and a nucleophilic carbon) with the formation of N-C2 and C3-C4 bonds.

The reaction of α-aminoketones with alkynes proceeds with the nucleophilic addition of amino group to the electrophilic carbon of alkyne with the formation of enamine intermediate which on intramolecular cyclization provides pyrroles involving nucleophilc(β-carbon of the enamine intermediate)-electrophilic (carbonyl carbon) 12 interaction with the formation of C3-C4 bond.

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The reaction of β-amino-α,β-unsaturated esters 91(three atom fragment) with nitroalkenes(two atom fragment) provides substituted pyrrole involving (3+2) 13 cyclization with N-C2 and C3-C4 bonds.

Base catalysed (3+2) cyclizative condensation of α-diketones with amines substituted with electron withdrawing substituents at α, α’-positions results in the 14 corresponding pyrroles with the formation of C2-C3 and C4-C5 bonds.

The reaction of β-ketoesters with α-haloketones or aldehydes in the presence of ammonia or primary amine affords pyrroles involving (2+2+1) cyclization with the

formation of N-C2, C3-C4 and N-C5 bonds. (Hantzsch Synthesis). The reaction proceeds via stabilized enamine intermediate which on C-alkylation and N-alkylation by α-haloketone leads to the formation of corresponding pyrrole.

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The condensation of aliphatic aldehydes or ketones with hydrazine under strongly acidic conditions affords pyrroles involving (3+3) sigmatropic rearrangement and cyclization. (Piloty-Robinson Synthesis). This reaction can also be applied for the preparation of N-substituted pyrroles by condensing ketones with methyl hydrazine or N,N’-dimethyl hydrazine.15

The reaction of benzoin with benzyl aryl ketones in the presence of ammonium acetate results in the formation of polyaryl substituted pyrroles involving (2+2+1) cyclization.16

The condensation of alkyl isocyanoacetates with aldehydes in 2:1 ratio proceeds to involve an initial conjugated addition followed by an anionic cyclization 17 with the formation of C2-C3, C3-C4 and C4-C5 bonds.

It is the most general method and involves (4+1)cyclizative condensation of

1,4-dikitones(enolizable) with ammonia or its derivatives with the formation of N-C2

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1-6, 18-19 and N-C5 bonds . The reaction is considered to proceed with the successive attacks of nucleophilic nitrogen on the carbonyl carbon and finally followed by dehydration (aromatization) for which driving force is provided by the stability of the resulting pyrrole.

Metal ion assisted amination of 1,4-dienes or diynes with primary amines followed by cyclization provides N-substituted pyrroles.20-21

2-Acylaziridines undergo ring expansion reactions to provide pyrroles involving ring-opened dipolar intermediates.22

Vinylazirines also undergo ring expansion reactions, but two isomeric pyrroles are obtained depending on the reaction conditions. Thermal reactions involve a

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nitrene intermediate, while photochemical reaction proceeds via a nitrile ylide intermediate.23

The complex ring systems, formed by (3+2) cycloaddition of activated alkynes substituted with electron-withdrawing substituents, with mesoionic heterocycles, undergo extrusion reactions with the cleavage of larger ring leaving the pyrrole ring system intact.24-26

O E E O O- E O E E + + N N R -CO2 N R E R

E = COOCH3

E E N R1 R2 E E + N+ R2 N R1 - R O R

E = COOCH3

E E S R1 E E + + N N R1 R O- R

E = COOCH 3

Ethyl-3-amino-5-phenyl-1H-pyrrol-2-carboxylate found to be a useful intermediate in the sysnthesis of other nitrogen heterocycles.27 However Elliott and co-workers28-29 have described that condensation of aldehyde with aminomalonate

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gave 3-substituted enamine, which was cyclized in the presence of sodium methoxide to give 3-amino-4-benzyl-1H-pyrrol-2-carboxylate.

Using a similar approach toward the synthesis of pyrrole, Ning Chen, et. al30 were failed to synthesize 2-substituted enamine intermediate from benzoyl acetonitrile and diethyl aminomalonate using standard conditions such as azeotropic removal of 31 32 water, dehydration with molecular sieves or Lawis acid catalysis(TiCl4 , BF3.OEt2)

NH2 NC CN H2N EtOOC Ph EtOOC COOEt N Ph EtOOC EtOOCN Ph O H H

Considering the lower electrophilicity of the aryl ketone compared to the aldehyde, an alternative strategy for preparing enamine was examined. Since amines are known to undergo substitution reactions with chloro- and alkylthio-substituted olefins to yield enamines33, a similar approach was considered and the reaction of p- toluenesulfonyl enol ester of α-cyano ketone with diethyl aminomalonate was investigated. Tosylate was prepared by reacting benzoyl acetonitrile with p- toluenesulfonic anhydride (1.2 equiv) in dichloromethane and triethylamine (1.5 equiv) in 99% yield. When a mixture of tosylate and diethyl aminomalonate hydrochloride (1.2 equiv) were treated with an ethanolic solution of sodium ethoxide (0.2 M, 3.5 equiv)34, the pyrrole was directly obtained without isolation of enamine. Addition of the amine, cyclization and decarboxylation occurred in one-pot at room temperature to give a 46% overall yield of from benzoyl acetonitrile.

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In continuation with this study prior work at Saurashtra University on 1H- pyrrole derrivatives clubed with substituted-1,3,4-Oxadiazoles, 1-[2,4-dimethyl-5-(5- phenyl-1,3,4-oxadiazol-2-yl)-1H-pyrrol-3-yl]ethanone derivatives were synthesized. The synthetic stretagy follows starting with acid catalysed cyclocondensation of ethyl ester derivative of 3-amino-2-butenoic acid (generated insitu from ethylacetoacetate upon oximenation followed by reduction) with acetylacetone to afford ethyl-3-acetyl- 2,4-dimethyl-1H-pyrrole-5-carboxylate, which was derivatized into corresponding hydrazide derivative on treatment with hydrazine hydrate. The hydrazide derivative on reaction with different aromatic and heteroaromatic acid, in the presence of phosphorous oxychloride affords 1-[2,4-dimethyl-5-(5-phenyl-1,3,4-oxadiazol-2-yl)- 1H-pyrrol-3-yl]ethanone derivatives.35-36

H C O H3C O 3 H3CO O CH3 O O N O CH3 C2H5 C H NH 2 5 C2H5 2 O O OH O O 1

O O O H3C CH3 H3C CH3 H3C CH3 O R H2NHN O N CH C2H5 CH N CH OH N 3 N 3 N 3 O H O H O H R

A range of 2,5-disubstituted and 2,4,5-trisubstituted pyrroles can be

synthesized from dienyl azides at room temperature using ZnI2 or Rh2(O2CC3F7)4 as catalysts.37

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The CuI/N,N-dimethylglycine-catalyzed reaction of amines with γ-bromo- substituted γ,δ-unsaturated ketones in the presence of K3PO4 and NH4OAc gave the corresponding polysubstituted pyrroles in very good yields.38

Two methods for the regioselective synthesis of tetra- and trisubstituted N-H pyrroles from starting vinyl azides have been developed: A thermal pyrrole formation via the 1,2-addition of 1,3-dicarbonyl compounds to 2H-azirine intermediates generated in situ from vinyl azides and a Cu(II)-catalyzed synthesis with ethyl acetoacetate through a 1,4-addition. 39

R1 O R O O R 1 toluene, 100°C, 2-5 h + R N N3 H

An operationally simple, practical, and economical Paal-Knorr pyrrole condensation of 2,5-dimethoxytetrahydrofuran with various amines and sulfonamines in water in the presence of a catalytic amount of iron(III) chloride allows the synthesis of N-substituted pyrroles under very mild reaction conditions in good to excellent yields. 40

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A new and efficient three-component reaction between dialkyl acetylenedicarboxylates, aromatic amines, triphenylphosphine, and arylglyoxals afforded polysubstituted pyrrole derivatives in high yields. The reactions were performed in dichloromethane at room temperature and under neutral conditions. 41

A three-component reactions of arylacyl bromides, amines, and dialkyl acetylenedicarboxylate in the presence of iron(III) chloride as a catalyst at room temperature afforded polysubstituted pyrroles in high yields. 42

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2.3 PHARMACOLOGY

Pyrrole has its own pharmaceutical importance and various activities of pyrrole include: ¾ Selective Mono Amine Oxidase type A Inhibitors 44-57 ¾ Antitubercular activities 58-66 ¾ HIV-1 intigrase Inhibitors 67-69 ¾ Antiproliferative activity 70-71 ¾ Glycogen Synthase Kinase-3(GSK-3) Inhibitors 72-79 ¾ Analgesic and Antiinflammatory activity 80-81 ¾ Bactericidal activities 82-86 ¾ Fungicides and Plant Growth Regulators 87-89 ¾ Action on the Cardiovascular System 90-94 ¾ Neuronal L-type Calcium channel activator 95

2.4 SOME DRUGS FROM PYRROLE NUCLEUS 44-95 .

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2.5 AIM OF CURRENT WORK

In continuation with our study on pyrrole derrivatives reveals that pyrrole moiety contacting heterocyclic molecules exhibits significance biological potential. Thus to synthesize novel pyrrole derivatives we utilized 4-amino coumarin, nitro methane, substituted aldehydes and α-diketo compounds in presence of lewis acid to afford of 4-(3-(substituted)benzoyl-2-alkyl-5-(substituted) alkyl-4-(substituted) phenyl-1H-pyrrol-1-yl)-2H-chromene-2-ones.

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2.6 REACTION SCHEMES

2.6.1 PREPARATION OF BENZOYL ACETONES :

Reagents / Reaction Condition (a): Ethyl Acetate, C2H5ONa/ 0-5°C, 2 hours.

2.6.2 PREPARATION OF 4-AMINO COUMARIN :

Reagents / Reaction Condition (b): Ammonium Acetate, MW 300W, 10-15 min.

2.6.3 PREPARATION OF 4-(3-(SUBSTITUTED)BENZOYL-2-ALKYL-5- (SUBSTITUTED)ALKYL-4-(SUBSTITUTED)PHENYL-1H-PYRROL-1- YL)-2H-CHROMENE-2-ONES/QUINOLIN-2(1H)-ONES

R2 R3 OO OO O c R1 + N + R1 R2 + R3-CHO + N O- NH2 O O

R1=CH3,CH2Cl, etc. R2=H,4-F,2,4-diCl R3= substituted phenyl, thiophene, etc.

Reagents / Reaction Condition (c): Ammonium Acetate, MW 300W, 2 min.

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2.7 PLAUSIBLE REACTION MECHANISM

R .. NH O R3 R1 R2 H R 2 OH NO2 .. N R1 NH O R R3 H

H R R2 3 H OH N R1 N OH R

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2.8 EXPERIMENTAL

2.8.1 MATERIALS AND METHODS Melting points were determined in open capillary tubes and are uncorrected. Formation of the compounds was routinely checked by TLC on silica gel-G plates of 0.5 mm thickness and spots were located by iodine and UV. IR spectra were recorded in Shimadzu FT-IR-8400 instrument using KBr method. Mass spectra were recorded on Shimadzu GC-MS-QP-2010 model using Direct Injection Probe technique. 1H

NMR was determined in CDCl3/DMSO solution on a Bruker Ac 400 MHz spectrometer.

2.8.2 PREPARATION OF BENZOYL ACETONES:

A mixture of Sodium Ethoxide (0.2 mol), Ethyl acetate (0.2 mol) were taken in 250 ml RBF then slowely add (0.05 mol) of aceto phenone to the mixture below 5°C. After addition of acetophenone to it allow it for one day in freeze and pour it to ice water mixture. Then acidify it by glacial acetic acid to get product. After that filter the product and wash with chilled water to remove acidity and dry it.

2.8.3 PREPARATION OF 4-AMINO COUMARIN

A mixture of 4-hydroxy coumarin (1.0 mmol) and ammonium acetate (3.0 mmol) was taken in a R.B.F. and placed in microwave oven and irradiated at 300W for 10-15 minutes. After observation of TLC, the reaction was allowed to cool and the

product was allowed to stir in 20ml 10% NaHCO3 solution for 1 h, filtered and washed with water further recrystallized from methanol to yield 35%., 4-amino coumarin with m.p. 230–232°C. (ARKIVOC, (10), 2010, 62-76) .

2.8.4 PREPARATON OF SUBSTITUTED PYRROLE

To a stirred solution of 4-amino coumarin (1.5 mmol), aromatic aldehyde (1 mmol) and α-diketo compound (1 mmol) in nitromethane (1 ml) was added anhydrous

ZnCl2 (0.1 mmol) and the mixture was heated to reflux slowly for 2-3 h and cooled down to room temperature, followed by addition of 5 ml methanol and allowed to

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Chapter – 2 Synthesis N-substituted pyrrole derivatives reflux for 1 h and cooled down to room temperature, after confirmation from TLC obtain desired compound was filtered and washed with methanol to yield crystalline solid. In some compounds if solid do not precipitates out, the excess solvent was removed under vacuum, and to the residue was added petroleum ether and allowed to crystallize the product at room temperature and isolated in 60-80% yield.

The physical constants of newly synthesized compounds are given in Table No.1

2.9 PHYSICAL DATA

Physical data of 4-(3-(substituted)benzoyl-2-alkyl-5-(substituted) alkyl-4-(substituted)phenyl-1H-pyrrol-1-yl)-2H-chromene-2-ones

TABLE – 1

Sr. Code R R R M.P. R No. 1 2 3 f

1 BAJ-201 CH3 C6H5 C6H5 180-182 0.50

2 BAJ-202 CH3 4-F-C6H4 C6H5 204-206 0.49

3 BAJ-203 CH3 2,4-di-Cl- C6H3 C6H5 226-228 0.47

4 BAJ-204 CH3 O-CH(CH3)2 C6H5 208-210 0.43

O-CH2- 5 BAJ-205 CH3 C6H5 196-198 0.44 CH(CH3)2

6 BAJ-206 CH3 C6H5 3-Br-C6H4 188-190 0.45

7 BAJ-207 CH3 4-F-C6H4 3-Br-C6H4 210-212 0.44

8 BAJ-208 CH3 2,4-di-Cl- C6H3 3-Br-C6H4 178-180 0.48

9 BAJ-209 CH3 O-CH(CH3)2 3-Br-C6H4 186-188 0.43

O-CH2- 10 BAJ-210 CH3 3-Br-C6H4 168-170 0.48 CH(CH3)2

11 BAJ-211 CH3 C6H5 C6H4-3-O-C6H5 194-196 0.45

12 BAJ-212 CH3 4-F-C6H4 C6H4-3-O-C6H5 206-208 0.39

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13 BAJ-213 CH3 2,4-di-Cl- C6H3 C6H4-3-O-C6H5 178-180 0.48

14 BAJ-216 CH3 CH3 C6H5 166-168 0.47

15 BAJ-217 CH3 CH3 3-Br-C6H4 218-220 0.48

16 BAJ-218 CH3 CH3 C6H4-3-O-C6H5 208-210 0.44

17 BAJ-219 CH3 C6H5 2-Thiophenyl 178-180 0.48

18 BAJ-220 CH3 4-F-C6H4 2-Thiophenyl 212-214 0.50

19 BAJ-221 CH3 2,4-di-Cl- C6H3 2-Thiophenyl 202-204 0.40

20 BAJ-222 CH3 CH3 2-Thiophenyl 182-184 0.44

21 BAJ-225 CH3 C6H5 4-F-C6H4 176-178 0.48

22 BAJ-226 CH3 4-F-C6H4 4-F-C6H4 218-220 0.42

23 BAJ-227 CH3 2,4-di-Cl- C6H3 4-F-C6H4 192-194 0.47

24 BAJ-228 CH3 O-CH(CH3)2 4-F-C6H4 188-190 0.46

O-CH2- 25 BAJ-229 CH3 4-F-C6H4 178-180 0.44 CH(CH3)2

26 BAJ-231 CH3 C6H5 4-Me-C6H4 212-214 0.48

27 BAJ-232 CH3 4-F-C6H4 4-Me-C6H4 202-204 0.40

28 BAJ-233 CH3 2,4-di-Cl- C6H3 4-Me-C6H4 182-184 0.42

29 BAJ-234 CH3 CH3 4-Me-C6H4 176-178 0.45

30 BAJ-237 CH2-Cl O-CH2-CH3 C6H5 218-220 0.49

31 BAJ-238 CH2-Cl O-CH2-CH3 3-Br-C6H4 192-194 0.52

32 BAJ-239 CH2-Cl O-CH2-CH3 C6H4-3-O-C6H5 188-190 0.48

33 BAJ-240 CH2-Cl O-CH2-CH3 4-F-C6H4 222-224 0.55

34 BAJ-241 CH2-Cl O-CH2-CH3 4-Me-C6H4 196-198 0.44

Rf value was determined using solvent system = Ethyl Acetate : Hexane (4 : 1)

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2.10 SPECTRAL DISCUSSION

2.10.1 IR SPECTRA

IR spectra of the synthesized compounds were recorded on Shimadzu FT-IR 8400 model using KBr pallet method. Various functional groups present were identified by characteristic frequency obtained for them. The characteristic bands of (-C=O) were obtained for stretching at 1650-1750 cm-1. The stretching vibrations (–C-O-C-) group showed in the finger print region of 1100-1050 cm-1. (-C-N-) stretching was observed at 1400-1350 cm-1. It gives aromatic (-C-H-) stretching frequencies between 3200-3000 and ring skeleton (- C=C-) stretching at 1500-1350 cm-1 C-H stretching frequencies for methyl and methylene group were obtained near 2950 - 2850 cm-1.

2.10.2 MASS SPECTRA

2.10.3 1H NMR SPECTRA

1H NMR spectra of the synthesized compounds were recorded on Bruker

Avance II 400 spectrometer by making a solution of samples in DMSO-d6 solvent using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned. Numbers of protons and carbons identified from 1H NMR spectrum and their chemical shift (δ ppm) were in the agreement of the structure of the molecule. J values were calculated to identify o, m and p coupling. In some cases, aromatic protons were obtained as multiplet. Interpretation of representative spectra is discussed further in this chapter.

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1.10.4 13C NMR SPECTRA

13C NMR spectra of the synthesized compounds were recorded on Bruker

Avance II 300 spectrometer by making a solution of samples in DMSO-d6 solvent using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned. Types of carbons identified from NMR spectrum and their chemical shift (δ ppm) were in the agreement of the structure of the molecule. Aliphatic carbon was observed between 15-25 δ ppm and alkene carbon at 100-102 δ ppm. Aromatic carbon was observed between 115-140 δ ppm while aliphatic keto carbon was observed at 158-160 and aromatic keto carbon was observed at 190-195 δ ppm. Aromatic carbon attached to hetero atom was observed at 155-157 δ ppm.

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2.11 ANALYTICAL DATA

4-(3-Acetyl-2-methyl-4-phenyl-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-201) IR (cm-1): 3082,3014 (aromatic -C-H stretching), 2974,2901 (aliphatic -C-H stretching), 1708(-C=O stretching), 1353 (-C-N stretching), 1021(-C-O-C stretching), + 981 (-C-H bending) , MS: m/z = 343 (M ), % Anal. Calcd. for C22H17NO3: C, 76.95; H, 4.99; N, 4.08; O, 13.98.

4-(3-(4-Fluorobenzoyl)-2-methyl-4-phenyl-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-202) IR (cm-1): 3189,3086 (aromatic -C-H stretching), 2908,(aliphatic -C-H stretching), 1691(-C=O Stretching), 1315(-C-N stretching), 1042(-C-F stretching), 1003(-C-O-C stretching), 717(-C-H bending monosubstituted), MS: m/z = 423 (M+), 424 (M+1); %

Anal. Calcd. for C27H18FNO3: C, 76.59; H, 4.28; F, 4.49; N, 3.31; O, 11.34.

4-(3-(2,4-Dichlorobenzoyl)-2-methyl-4-phenyl-1H-pyrrol-1-yl)-2H-chromen-2- one (BAJ-203) IR (cm-1): 3032,3024 (aromatic -C-H stretching), 2984 (aliphatic -C-H stretching), 1690(-C=O Stretching), 1361(-C-N stretching), 1048(-C-O-C stretching), 756(-C-Cl stretching), 699(-C-H bending m-disubstituted), MS: m/z = 474 (M+), 476 (M+2); %

Anal. Calcd. for C27H17Cl2NO3: C, 68.37; H, 3.61; Cl, 14.95; N, 2.95; O, 10.12.

Isopropyl-2-methyl-1-(2-oxo-2H-chromen-4-yl)-4-phenyl-1H-pyrrole-3- carboxylate (BAJ-204) IR (cm-1): 3062,3034 (aromatic- C-H stretching), 2984,2901 (aliphatic -C-H

stretching), 2894(aliphatic -CH stretching), 1693(-C=O stretching), 1263 (-C-N stretching), 1095(-C-O-C stretching), 1082 (-C-H bending), MS: m/z = 387 (M+); %

Anal. Calcd. for C24H21NO4: C, 74.40; H, 5.46; N, 3.62; O, 16.52.

Isobutyl-2-methyl-1-(2-oxo-2H-chromen-4-yl)-4-phenyl-1H-pyrrole-3- carboxylate (BAJ-205) IR (cm-1): 3032,3014 (aromatic -C-H stretching), 2974,2961 (aliphatic -C-H

stretching), 2823 (aliphatic -CH2 stretching), 1669(-C=O stretching), 1428,1382 (-C-

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H bending), 1262 (-C- N stretching), 1088 (-C-H bending), 1005(-C-O-C stretching), + 981 (-C-H bending), MS: m/z = 401 (M ); % Anal. Calcd. for C25H23NO4: C, 74.79; H, 5.77; N, 3.49; O, 15.94.

4-(3-Benzoyl-4-(3-bromophenyl)-2-methyl-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-206) IR (cm-1): 3052,3026 (aromatic -C-H stretching), 2944,2956 (aliphatic -C-H stretching), 1662(-C=O stretching), 1323 (-C-N stretching), 1015(-C-O-C stretching), 702 (-C-H bending monosubstituted), 542 (-C-Br stretching), MS: m/z = 484 (M+), +2 486 (M ), % Anal. Calcd. for C27H18BrNO3: C, 66.95; H, 3.75; Br, 16.50; N, 2.89; O, 9.91.

4-(4-(3-Bromophenyl)-3-(4-fluorobenzoyl)-2-methyl-1H-pyrrol-1-yl)-2H- chromen-2-one (BAJ-207) IR (cm-1): 3189, 3064(aromatic -C-H stretching), 2941(aliphatic -C-H stretching), 1658(-C=O Stretching), 1585, 1500(-C=C- ring strain), 1309(-C-N stretching), 1124(- C-O-C stretching), 1010(-C-F stretching), 711(-C-H bending monosubstituted), 597(- 1 C-Br stretching), H NMR (DMSO-d6) δ ppm: 3H, s (2.20), 1H s (5.03), 1H, d (7.06- 7.08, J=8.0 Hz), 2H, m (7.11-7.18), 5H, m (7.25-7.38), 1H, d (7.49-7.50 , J=4.0 Hz ), 1H,m (7.56-7.60), 1H, s (8.05), 1H, m (8.33-8.35, J=8.0 Hz), 13C: 18.60, 101.42, 111.76, 112.71, 116.62, 121.43,122.84, 123.57, 126.45, 127.30, 128.96, 129.20, 129.25, 129.82, 130.41, 130.47, 131.57, 138.87, 139.69, 141.60, 147.41, 147.91, 152.15, 160.25, 191.49. MS: m/z = 502 (M+), 504 (M+2); % Anal. Calcd. for

C27H17BrFNO3: C, 64.56; H, 3.41; Br, 15.91; F, 3.78; N, 2.79; O, 9.56.

4-(4-(3-Bromophenyl)-3-(2,4-dichlorobenzoyl)-2-methyl-1H-pyrrol-1-yl)-2H- chromen-2-one (BAJ-208) IR (cm-1): 3036,3012 (Aromatic -C-H stretching), 2956 (Aliphatic -C-H stretching), 1677(-C=O Stretching), 1353(-C-N stretching), 1009(-C-O-C stretching), 784(-C-Cl stretching), 713 (-C-H bending monosubstituted), 653(-C-H bending m-disubstituted), 532(-C-Br stretching) MS: m/z = 553 (M+), 555 (M+2); % Anal. Calcd. for

C27H16BrCl2NO3: C, 58.62; H, 2.92; Br, 14.44; Cl, 12.82; N, 2.53; O, 8.68.

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Isopropyl-4-(3-Bromophenyl)-2-methyl-1-(2-oxo-2H-chromen-4-yl)-1H-pyrrole- 3-carboxylate (BAJ-209) -1 IR (cm ): 3026,3043 (aromatic -C-H stretching), 2948,2910 (aliphatic -CH3 stretching), 1689(-C=O stretching), 1236 (-C-N stretching), 1099(-C-O-C stretching), 722 (-C-H bending monosubstituted), 582(-C-Br stretching), MS: m/z = 466 (M+), +2 468 (M ); % Anal. Calcd. for C24H20BrNO4: C, 61.81; H, 4.32; Br, 17.13; N, 3.00; O, 13.72.

Isobutyl-4-(3-bromophenyl)-2-methyl-1-(2-oxo-2H-chromen-4-yl)-1H-pyrrole-3- carboxylate (BAJ-210) -1 IR (cm ): 3052,3023 (Aromatic -C-H stretching), 2998,2924 (Aliphatic -CH3 stretching), 2854 (Aliphatic -CH2 Stretching), 1698(-C=O stretching), 1423,1397 (-C- H bending), 1223(-C-N stretching), 988(-C-O-C stretching), 718(-C-H bending monosubstituted), 591(-C-Br stretching), MS: m/z = 480 (M+), 482 (M+2); % Anal.

Calcd. for C25H22BrNO4: C, 62.51; H, 4.62; Br, 16.63; N, 2.92; O, 13.32.

4-(3-Benzoyl-2-methyl-4-(3-phenoxyphenyl)-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-211) IR (cm-1): 3078,3021 (Aromatic -C-H stretching), 2944,2909 (Aliphatic -C-H stretching), 1660(-C=O stretching), 1332(-C-N stretching), 1023(-C-O-C stretching), 984(-C-H bending) , 739(-C-H bending monosubstituted), MS: m/z = 497 (M+), %

Anal. Calcd. for C33H23NO4: C, 79.66; H, 4.66; N, 2.82; O, 12.86.

4-(3-(4-Fluorobenzoyl)-2-methyl-4-(3-phenoxyphenyl)-1H-pyrrol-1-yl)-2H- chromen-2-one (BAJ-212) IR (cm-1): 3198,3068 (Aromatic -C-H stretching), 2964,(Aliphatic -C-H stretching), 1693(-C=O Stretching), 1344(-C-N stretching), 1063(-C-F stretching), 1003(-C-O-C stretching), 729(-C-H bending monosubstituted), MS: m/z = 515 (M+), 516 (M+1); %

Anal. Calcd. for C33H22FNO4: C, 76.88; H, 4.30; F, 3.69; N, 2.72; O, 12.41.

4-(3-(2,4-Dichlorobenzoyl)-2-methyl-4-(3-phenoxyphenyl)-1H-pyrrol-1-yl)-2H- chromen-2-one (BAJ-213) IR (cm-1): 3088, 3064(aromatic -C-H stretching), 2953(aliphatic -C-H stretching), 1676(-C=O Stretching), 1577, 1479(-C=C- ring strain), 1394(-C-N stretching), 1062(-

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

C-O-C stretching), 754(-C-Cl stretching), 734(-C-H stretching monosubstituted), 1 673(-C-H bending m-disubstituted), H NMR (DMSO-d6) δ ppm: 3H, s (2.25), 1H, s (5.05), 1H, m (6.73-6.75), 1H, s (6.83), 2H, d (6.91-6.93, J= 8Hz), 2H, t (6.95-7.00), 1H, t (7.05-7.09), 1H, t (7.14-7.17), 1H, dd (7.23-7.25), 4H, m (7.28-7.34), 1H, d (7.40-7.41, J=1.8), 1H, t (7.53-7.57), 1H, s (7.70), 1H, d (8.25-8.27, J=8.0 Hz), 13C: 18.52, 101.77, 112.00, 112.79, 116.46, 116.55, 118.01, 118.10, 122.41, 122.57, 122.67, 123.29, 126.91, 128.82, 129.00, 129.20, 129.23, 130.61, 131.19, 134.95, 139.31, 141.38, 146.80, 147.08, 152.13, 156.27, 156,46, 160.55, 192.14. MS: m/z = + +2 566 (M ), 568 (M ); % Anal. Calcd. for C33H21Cl2NO4: C, 69.97; H, 3.74; Cl, 12.52; N, 2.47; O, 11.30.

4-(3-Acetyl-2-methyl-4-phenyl-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-216) IR (cm-1): 3098,3034 (aromatic -C-H stretching), 2990,2923 (aliphatic -C-H stretching), 1698(-C=O stretching), 1323 (-C-N stretching), 1032(-C-O-C stretching), + 934 (-C-H bending) , MS: m/z = 343 (M ), % Anal. Calcd. for C22H17NO3: C, 76.95; H, 4.99; N, 4.08; O, 13.98.

4-(3-Acetyl-4-(3-bromophenyl)-2-methyl-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-217) IR (cm-1): 3066(aromatic -C-H stretching), 2970(aliphatic -C-H stretching), 1660(- C=O stretching), 1598, 1566, 1502(-C=C- ring strain), 1354(-C-N stretching), 1056(- C-O-C stretching), 759(-C-H bending monosubstituted), 601(-C-Br stretching), 1H

NMR (DMSO-d6) δ ppm: 3H, s (2.20), 3H, s (2.58), 1H,s (5.15), 1H, t (7.13-7.17), 4H, m (7.25-7.36), 1H, s(7.48), 1H, t (7.52-7.56), 1H, s (7.72), 1H, d (8.25-8.27, J=8. 08 Hz), 13C: 19.01, 29.67, 100.86, 111.29, 112.83, 116.52, 121.91, 122.42, 123.30, 126,34, 129.36, 129.70, 130.24, 131.20, 141.64, 144.92, 147.16, 152.07, 160.85, + +2 197.23. MS: m/z = 422 (M ), 424 (M ); % Anal. Calcd. for C22H16BrNO3: C, 62.57; H, 3.82; Br, 18.92; N, 3.32; O, 11.37.

4-(3-Acetyl-2-methyl-4-(3-phenoxyphenyl)-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-218) IR (cm-1): 3087,3034 (Aromatic -C-H stretching), 2989,2923 (Aliphatic -C-H stretching), 1643(-C=O stretching), 1334(-C-N stretching), 1022(-C-O-C stretching),

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932(-C-H bending) , 732(-C-H bending monosubstituted), MS: m/z = 435 (M+); %

Anal. Calcd. for C28H21NO4: C, 77.23; H, 4.86; N, 3.22; O, 14.70.

4-(3-Benzoyl-2-methyl-4-(thiophen-2-yl)-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-219) IR (cm-1): 3094,3023 (aromatic -C-H stretching), 2989,2943 (aliphatic -C-H stretching), 1688(-C=O stretching), 1312(-C-N stretching), 1002(-C-O-C stretching), 981 (-C-H bending), 866 (-C-S stretching) MS: m/z = 411 (M+), % Anal. Calcd. for

C25H17NO3S: C, 72.97; H, 4.16; N, 3.40; O, 11.66; S, 7.79.

4-(3-Benzoyl-2-methyl-4-(thiophen-2-yl)-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-220) IR (cm-1): 3103, 3074(aromatic -C-H stretching), 2991(aliphatic -C-H stretching), 1670(-C=O Stretching), 1508, 1477(-C=C- ring strain), 1338(-C-N stretching), 1128(- C-O-C stretching), 1025(-C-F stretching), 848(-C-S stretching), 748(-C-H bending 1 monosubstituted), H NMR (DMSO-d6) δ ppm: 3H, s (2.05), 1H, s (5.41), 1H, d (6.77-6.78, J=3.24 Hz), 1H, m (6.81-6.83), 1H, dd (7.08-7.10), 2H, m (7.12-7.18), 2H, m (7.31-7.37), 1H, m (7.56-7.60), 2H, m (7.65-7.70), 1H, s (7.90), 1H, dd (8.29- 8.32), 13C: 18.34, 99.29, 112.28,113.03, 115.16,115.38, 116.6, 122.69, 123.28, 123.40, 123.59, 126.35, 130.54, 130.63, 131.32, 135.79, 135.82, 140.89, 142.34, 148.97, 152.13, 160.60, 163.06, 165.57, 194.95. MS: m/z = 429 (M+), 430 (M+1); %

Anal. Calcd. for C25H16FNO3S: C, 69.92; H, 3.76; F, 4.42; N, 3.26; O, 11.18; S, 7.47.

4-(3-(2,4-Dichlorobenzoyl)-2-methyl-4-(thiophen-2-yl)-1H-pyrrol-1-yl)-2H- chromen-2-one (BAJ-221) IR (cm-1): 3091,3057 (aromatic -C-H stretching), 2953 (aliphatic -C-H stretching), 1696(-C=O Stretching), 1325(-C-N stretching), 1034(-C-O-C stretching), 849(-C-S streching), 746(-C-Cl stretching), 659(-C-H bending m-disubstituted), MS: m/z = 480 + +2 (M ), 482 (M ); % Anal. Calcd. for C25H15Cl2NO3S: C, 62.51; H, 3.15; Cl, 14.76; N, 2.92; O, 9.99; S, 6.68.

4-(3-Acetyl-2-methyl-4-(thiophen-2-yl)-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ- 222)

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IR (cm-1): 3088,3062 (aromatic -C-H stretching), 2995,2952 (aliphatic -C-H stretching), 1695(-C=O stretching), 1334 (-C-N stretching), 1014(-C-O-C stretching), 954 (-C-H bending), 856(-C-S stretching), MS: m/z = 349 (M+), % Anal. Calcd. for

C20H15NO3S: C, 68.75; H, 4.33; N, 4.01; O, 13.74; S, 9.18.

4-(3-Benzoyl-4-(4-fluorophenyl)-2-methyl-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-225) IR (cm-1): 3175,3064 (aromatic -C-H stretching), 2966,(aliphatic -C-H stretching), 1623(-C=O Stretching), 1306(-C-N stretching), 1102(-C-F stretching), 1053(-C-O-C stretching), 713(-C-H bending monosubstituted), MS: m/z = 423 (M+), 424 (M+1); %

Anal. Calcd. for C27H18FNO3: C, 76.59; H, 4.28; F, 4.49; N, 3.31; O, 11.34.

4-(3-(4-Fluorobenzoyl)-4-(4-fluorophenyl)-2-methyl-1H-pyrrol-1-yl)-2H- chromen-2-one (BAJ-226) IR (cm-1): 3194,3059 (aromatic -C-H stretching), 2947,(aliphatic -C-H stretching), 1675(-C=O Stretching), 1366(-C-N stretching), 1093(-C-F stretching), 1029(-C-O-C stretching), 748(-C-H bending monosubstituted), MS: m/z = 441 (M+), 442 (M+2); %

Anal. Calcd. for C27H17F2NO3: C, 73.46; H, 3.88; F, 8.61; N, 3.17; O, 10.87.

4-(3-(2,4-Dichlorobenzoyl)-4-(4-fluorophenyl)-2-methyl-1H-pyrrol-1-yl)-2H- chromen-2-one (BAJ-227) IR (cm-1): 3096,3060 (aromatic -C-H stretching), 2455 (aliphatic -C-H stretching), 1675(-C=O Stretching), 1384(-C-N stretching), 1073(-C-O-C stretching), 1015(-C-F stretching), 795(-C-Cl stretching), 710(-C-H bending monosubstituted), 679(-C-H bending m-disubstituted), MS: m/z = 492, (M+), 494 (M+2); % Anal. Calcd. for

C27H16Cl2FNO3: C, 65.87; H, 3.28; Cl, 14.40; F, 3.86; N, 2.85; O, 9.75.

Isopropyl-4-(4-Fluorophenyl)-2-methyl-1-(2-oxo-2H-chromen-4-yl)-1H-pyrrole- 3-carboxylate (BAJ-228) IR (cm-1): 3078,3029 (aromatic -C-H stretching), 2995,2947 (aliphatic -C-H

stretching), 2887(aliphatic -CH stretching), 1693(-C=O stretching), 1263 (-C-N stretching), 1095(-C-O-C stretching), 1082 (-C-H bending), 1036(-C-F stretching), 730(-C-H bending monosubstituted), MS: m/z = 405 (M+), 406 (M+1); % Anal.

Calcd. for C24H20FNO4: C, 71.10; H, 4.97; F, 4.69; N, 3.45; O, 15.79.

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Isobutyl-4-(4-Fluorophenyl)-2-methyl-1-(2-oxo-2H-chromen-4-yl)-1H-pyrrole-3- carboxylate (BAJ-229) IR (cm-1): 3085,3029 (aromatic -C-H stretching), 2985,2912 (aliphatic -C-H

stretching), 2817 (aliphatic -CH2 Stretching), 1634(-C=O stretching), 1428,1382 (-C- H bending), 1235 (-C- N stretching), 1102(-C-F stretching), 1074 (-C-H bending), 1005(-C-O-C stretching), 981 (-C-H bending), 730(-C-H bending monosubstituted), + +1 MS: m/z = 419 (M ), 420 (M ); % Anal. Calcd. for C25H22FNO4: C, 71.59; H, 5.29; F, 4.53; N, 3.34; O, 15.26.

4-(3-Benzoyl-2-methyl-4-(p-tolyl)-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-231) IR (cm-1): 3189,3086 (aromatic -C-H stretching), 2908,(aliphatic -C-H stretching), 1691(-C=O Stretching), 1315(-C-N stretching), 1003(-C-O-C stretching), MS: m/z = + 419 (M ); % Anal. Calcd. for C28H21NO3: C, 80.17; H, 5.05; N, 3.34; O, 11.44.

4-(3-(4-Fluorobenzoyl)-2-methyl-4-(p-tolyl)-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-232) IR (cm-1): 3199,3096 (aromatic -C-H stretching), 2927,(aliphatic -C-H stretching), 1674(-C=O Stretching), 1328(-C-N stretching), 1096(-C-F stretching), 1013(-C-O-C stretching), 749(-C-H bending monosubstituted), MS: m/z = 437 (M+), 438 (M+1); %

Anal. Calcd. for C28H20FNO3: C, 76.88; H, 4.61; F, 4.34; N, 3.20; O, 10.97.

4-(3-(2,4-Dichlorobenzoyl)-2-methyl-4-(p-tolyl)-1H-pyrrol-1-yl)-2H-chromen-2- one (BAJ-233) IR (cm-1): 3061,3023 (aromatic -C-H stretching), 2943 (aliphatic -C-H stretching), 1673(-C=O Stretching), 1382(-C-N stretching), 1013(-C-O-C stretching), 753(-C-Cl stretching), 685(-C-H bending m-disubstituted), MS: m/z = 488 (M+), 490 (M+2); %

Anal. Calcd. for C28H19Cl2NO3: C, 68.86; H, 3.92; Cl, 14.52; N, 2.87; O, 9.83.

4-(3-Acetyl-2-methyl-4-(p-tolyl)-1H-pyrrol-1-yl)-2H-chromen-2-one (BAJ-234) IR (cm-1): 3094,3028 (aromatic -C-H stretching), 2976,2901 (aliphatic -C-H stretching), 1701(-C=O stretching), 1323 (-C-N stretching), 1021(-C-O-C stretching), 738(-C-H bending monosubstituted), MS: m/z = 357 (M+), % Anal. Calcd. for

C23H19NO3: C, 77.29; H, 5.36; N, 3.92; O, 13.43.

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Ethyl-2-(chloromethyl)-1-(2-oxo-2H-chromen-4-yl)-4-phenyl-1H-pyrrole-3- carboxylate (BAJ-237) IR (cm-1): 3081,3046 (aromatic -C-H stretching), 2953,2917 (aliphatic -C-H

stretching), 2849(aliphatic -CH2 stretching), 1669(-C=O stretching), 1428,1382 (-C- H bending), 1234 (-C-N stretching), 1103(-C-O-C stretching), 1053(-C-H bending), 772(-C-Cl stretching), MS: m/z = 407 (M+), 409 (M+2); % Anal. Calcd. for

C23H18ClNO4: C, 67.73; H, 4.45; Cl, 8.69; N, 3.43; O, 15.69.

Ethyl-4-(3-bromophenyl)-2-(chloromethyl)-1-(2-oxo-2H-chromen-4-yl)-1H- pyrrole-3-carboxylate (BAJ-238) IR (cm-1): 3087,3055 (aromatic -C-H stretching), 2975,2914 (aliphatic -C-H

stretching), 2823 (aliphatic -CH2 stretching), 1669(-C=O stretching), 1417,1376 (-C- H bending), 1229 (-C-N stretching), 1099(-C-O-C stretching), 1042(-C-H bending), 743(-C-Cl stretching), 589(-C-Br stretching), MS: m/z = 486 (M+), 488 (M+2); %

Anal. Calcd. for C23H17BrClNO4: C, 56.75; H, 3.52; Br, 16.42; Cl, 7.28; N, 2.88; O, 13.15.

Ethyl-2-(chloromethyl)-1-(2-oxo-2H-chromen-4-yl)-4-(3-phenoxyphenyl)-1H- pyrrole-3-carboxylate (BAJ-239) IR (cm-1): 3078,3021 (aromatic -C-H stretching), 2944,2909 (aliphatic -C-H

stretching), 2812(aliphatic -CH2 stretching), 1658(-C=O stretching), 1425,1386 (-C- H bending), 1239(-C-N stretching), 1104(-C-O-C stretching), 751(-C-Cl stretching), 711(-C-H bending monosubstituted), 574(-C-Br stretching), MS: m/z = 499 (M+), 501 +2 (M ); % Anal. Calcd. for C29H22ClNO5: C, 69.67; H, 4.44; Cl, 7.09; N, 2.80; O, 16.00.

Ethyl-2-(chloromethyl)-4-(4-fluorophenyl)-1-(2-oxo-2H-chromen-4-yl)-1H- pyrrole-3-carboxylate (BAJ-240) IR (cm-1): 3104,3061 (aromatic -C-H stretching), 2945,2903 (aliphatic -C-H

stretching), 2845 (aliphatic -CH2 stretching), 1683(-C=O stretching), 1422,1381 (-C- H bending), 1236 (-C-N stretching), 1093(-C-O-C stretching), 1015(-C-F stretching), 752(-C-Cl stretching), 717(-C-H bending monosubstituted), MS: m/z = 425 (M+),

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

+2 427 (M ); % Anal. Calcd. for C23H17ClFNO4: C, 64.87; H, 4.02; Cl, 8.33; F, 4.46; N, 3.29; O, 15.03.

Ethyl-2-(chloromethyl)-1-(2-oxo-2H-chromen-4-yl)-4-(p-tolyl)-1H-pyrrole-3- carboxylate (BAJ-241) IR (cm-1): 3094,3022 (aromatic -C-H stretching), 2974,2953(aliphatic -C-H

stretching), 2834 (aliphatic -CH2 stretching), 1691(-C=O stretching), 1412,1377 (-C- H bending), 1253 (-C-N stretching), 1012(-C-O-C stretching), 749(-C-Cl stretching), 711(-C-H bending monosubstituted), MS: m/z = 421 (M+), 423 (M+2); % Anal.

Calcd. for C24H20ClNO4: C, 68.33; H, 4.78; Cl, 8.40; N, 3.32; O, 15.17.

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.12 RESULTS AND DISCUSSION

According to the Grob and Cameisch, pyrroles can be obtained from Michael reaction of β-enamino ketones or esters and nitroalkenes followed by cyclization.96 However, only little has been explored in thisfield and reported only for aliphatic nitroalkenes.97 Moreover, in this method it is a prerequisite to prepare nitroalkenes from aldehyde and nitroalkanes, and β-enaminocarbonyl derivatives from β- dicarbonyl and amines beforehand. Consequently, there are opportunities for further improvement of this reaction. Present study reveals simultaneous one pot synthesis of β-keto-enamines from 1,3-dicarbonyl compounds and nitrostyrene from readily available starting materials in the presence of a suitable catalyst, and these two component undergo Michael reaction, to tandem synthesis of functionalized pyrroles.

2.13 CONCLUSION

In summary, we have successfully developed a novel, operationally simple, economical, and environmentally friendly one-pot four-component coupling reaction to synthesis functionalized pyrroles by employing 1,3-dicarbonyl compounds, aromatic aldehyde, amines, and nitro alkanes. Considering these advantages and experimental simplicity, this one-pot catalytic transformation clearly represents an appealing methodology for the synthesis of highly functionalized pyrroles. Further study in this area is going on in our laboratory to improve the yield, mechanism, and possible applications of this reaction.

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2.14 REPRESENTATIVE SPECTRA

2.14.1 IR Spectrum of BAJ-207

2.14.2 MASS Spectrum of BAJ-207

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.3 1H NMR Spectrum of BAJ-207

2.14.4 Expanded 1H NMR Spectrum of BAJ-207

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.5 13C NMR Spectrum of BAJ-207

2.14.6 IR Spectrum of BAJ-213

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.7 MASS Spectrum of BAJ-213

2.14.8 1H NMR Spectrum of BAJ-213

Cl O O Cl

H3C N

O O

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.9 Expanded 1H NMR Spectrum of BAJ-213

2.14.10 13C NMR Spectrum of BAJ-213

Cl O O Cl

H3C N

O O

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.11 IR Spectrum of BAJ-217

O Br H3C

H3C N

O O

2.14.12 MASS Spectrum of BAJ-217

O Br H3C

H3C N

O O

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.13 1H NMR Spectrum of BAJ-217

O Br H3C

H3C N

O O

2.14.14 Expanded 1H NMR Spectrum of BAJ-217

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.15 13C NMR Spectrum of BAJ-217

O Br H3C

H3C N

O O

2.14.16 IR Spectrum of BAJ-2220

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.17 MASS Spectrum of BAJ-220

2.14.18 1H NMR Spectrum of BAJ-220

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.14.19 Expanded 1H NMR Spectrum of BAJ-220

2.14.20 13C NMR Spectrum of BAJ-220

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Chapter – 2 Synthesis N-substituted pyrrole derivatives

2.15 REFERENCES

1. Jones, R., Bean, G.; The chemistry of pyrroles, Academic press, London 1977. 2. Gossauer, A.; Die chemie der pyrrole, Springer-Verleg, Berlin 1974. 3. Trofimov, B.; Usp. Chim., 1989, 58 , 1703. 4. Jones, R. (Ed.); Chem. Heterocycl. Compd., 1990, 48(1), Wiley Interscience, New York. 5. Jones, R. in E. C. Taylor(Ed.); Chem. Heterocycl. Compd., 48(2), 1992, Wiley Interscience, New York. 6. Sundberg, R. in A. R. Kartritzky and C.W.Rees(Eds.); Comprehensive Heterocyclic Chemistry, 1984, 4, 313. 7. Jones, R. in A. R. Kartritzky and C. W. Rees(Eds.), Comprehensive Heterocyclic Chemistry, 1984, 4, 201 8. Fabino, E., Golding, B.; J. Chem. Soc. Perk. Trans., 1991, 1, 3371. 9. Moss, G.; Pure Appl. Chem., 1987, 59, 807. 10. Curran, D., Grimshaw J., Perera S.; Chem. Soc. Rev., 1991, 20, 391. 11. Sundberg, R., Nguyen, P. in H.Suschitzky and E. Scriven(Edn.),; Progress in Heterocyclic Chemistry, 1994, 6,110. 12. Khetan, S., Hiriyakkanavar, J., George, M.; Tetrahedron, 1968, 24, 1567. 13. Meyer, H.; Leibigs, Ann. Chem., 1981, 1534. 14. Friedman, M.; J. Org. Chem., 1965, 30, 859. 15. Posvic, H., Dombro, R., Ito, H., Telinski, T.; J. Org. Chem., 1974, 39, 2575. 16. Tanaseichuk, B., Vlasova, S., Morozov, E.; Org. Khim Zh., 1971, 7, 1264. 17. Suzuki, M., Miyoshi, M., Matsumoto, K.; J. Org. Chem., 1974, 39, 1980. 18. Kartritzky, A., Suwinski, J.; Tetrahedron, 1975, 31, 1549 19. Kozlov, N., Moiseenok, L., Kozintsev, S.; Khim. Geterosikl. Soedin., 1979, 1483. 20. Backvall, J., Nystrom, J.; J. Chem. Soc. Chem. Commun., 1981, 59. 21. Makhsumov, A., Safaev, A., Madikhanov, N.; Khim. Geterosikl. Soedin., 1970, 125. 22. Chalk, A.; Tetrahedron.Lett., 1972, 3487. 23. Padwa, A., Dean D., Oine T.; J. Am. Chem. Soc., 1975, 97, 2822. 24. Padwa, A., Dean D., Oine T.; J. Am. Chem. Soc., 1975, 97, 2822.

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25. Huisgen, R., Gotthardt H., Bayer H., Schaefer F.; Chem. Ber., 1970, 103, 2611. 26. Potts, K., Chen S.; J. Org. Chem., 1977, 42, 1639. 27. Niitsuma, S., Kato, K, Takita, T., Umezawa, H.; Tetrahedron Lett., 1985, 26, 5785. 28. Elliott, A., Morris, P., Petty, S., Williams, C.; J. Org. Chem., 1997, 62, 8071. 29. Lim, M., Klein, R., Fox, J.; J. Org. Chem., 1979, 44, 3826. 30. Chen, N., Lu, Y., Gadamasetti, K., Hurt, C., Norman, M., Fotsch, C.; J. Org. Chem., 2000, 65, 2603. 31. (a) Furukawa, M., Okawara, T., Noguchi, Y., Terawaki, Y.; Chem. Pharm. Bull., 1979, 27, 2223. (b) Birnberg, G., Fanshawe, W., Francisco, G., Epstein J.; J. Heterocycl. Chem., 1995, 32, 1293. 32. (a) Carlson, R., Nilsson, A., Stroemqvist, M.; Acta Chem. Scand., B37, 1983, 7. (b) Selva, M., Tundo, P., Marques, C.; Synth. Commun., 1995, 25, 369. 33. (a) Erdmann, B., Knoll, A., Liebscher, J.; J. Prakt. Chem., 1988, 330, 1015. (b) Gewald, K., Schaefer, H., Bellmann, P., Hain, U., J.; Prakt. Chem., 1992, 334, 491. 34. Elliott, A., Montgomery, J., Walsh, A.; Tetrahedron Lett., 1996, 37, 4339. 35. Raval, K,; Ph.D. Thesis, Saurashtra University 2004. 36. Upadhyay, K,; Ph.D. Thesis, Saurashtra University 2006. 37. Dong, H., Shen, M., Redford, J. E., Stokes, B. J., Pumphrey, A. L., Driver, T. G.; Org. Lett., 2007, 9, 5191. 38. Pan, Y., Lu, H., Fang, Y., Fang, X., Chen, L., Qian, J., Wang, J., Li, C.; Synthesis, 2007, 1242-1246. 39. Chiba, S., Wang, Y.-F., Lapointe, G., Narasaka, K.; Org. Lett., 2008, 10, 313. 40. Azizi, N., Khajeh-Amiri A., Ghafuri, H., Bolourtchian, M., Saidi, M. R.; Synlett, 2009, 2245. 41. Anary-Abbasinejad, M., Charkhati, K., Anaraki-Ardakani, H.; Synlett, 2009, 1115. 42. Das, B., Reddy, G. C., Balasubramanyam, P., Veeranjaneyulu, B.; Synthesis, 2010, 1625. 43. Saito, A., Konishi, O., Hanzawa, Y.; Org. Lett., 2010, 12, 372. 44. Shih, J., Chen, K., Ridd, M.; Annu. Rev. Neurosci., 1999, 22, 197. 45. Shih, J., Thompson, R.; Am. J. Hum. Genet, 1999, 65, 593.

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46. Chiba, K., Trevor, A., Castagnoli, N.; Biochem. Biophys. Res. Commun., 1984, 120, 574. 47. Fritz, R., Abell, C., Patel, N., Gessner, W., Brossi, A.; FEBS Lett., 1985, 186, 224. 48. Grimsby, J., Toth, M., Chen, K., Kumazawa, T., Klaidman, L., Adams, J., Karoum, F., Gal, J., Shih, J.; Nat. Genet; 1997, 17, 206. 49. Zutter, G., Davis, R.; Proc. Natl. Acad. Sci. USA, 2001, 98, 6168. 50. Bach, A., Lan, N., Johnson, D., Abell, C., Bembenek, M., Kwan, S., Seeburg, P., Shih, J.; Proc. Natl. Acad. Sci. USA, 1988, 85, 4934. 51. Johnston, J.; Biochem. Pharmacol., 1968, 17, 1285. 52. Kalgutkar, A., Castagnoli, N., Testa, B.; Med. Res. Rev., 1995, 15, 325. 53. Westlund, R., Denney, R., Kochersperger, L., Rose, R., Abell, C.; Science 1985, 230,181. 54. Knoll, J., Magyar, K.; Adv. Biochem. Psycopharmacol., 1972, 5, 393. 55. Mai, A., Artico, M., Esposito, M., Ragno, R., Sbardella, G., Massa, S.; Il Farmaco, 2003, 58, 231. 56. Moureau, F., Wouters, J., Vercauteren, D., Collin, S., Evrard, G., Durant, F., Ducrey, F., Koenig, J., Jarreau, F.; Eur. J. Med. Chem., 1992, 27, 939. 57. Moureau F., Wouters J., Vercauteren D., Collin S., Evrard G., Durant F., Ducrey F., Koenig J., Jarreau F.; Eur. J. Med. Chem., 1994, 29, 269. 58. Collins, F.; Clin. Microbiol. Rev., 1989, 2, 360. 59. Dooley, S., Jarvis W., Marone W., Snider D; Ann. Intern. Med., 1992, 117, 257. 60. Fischl, M., Daikos, G., Uttamchandani, R., Poblete, R., Moreno, J., Reyes, R., Boota, A., Thompson, L., Cleary, T., Oldham, G., Saldama, M., Lai, S.; Ann. Intern. Med., 1992, 117, 184. 61. Heym, B., Honore, N., Truffot-Pernot, C., Banerjee, A., Schurra, C., Jacobs W., Van Embden J., Grosset J., Cole S.; Lancet, 1994, 344, 293. 62. Kochi, A.; Tubercle, 1991, 72, 1. 63. Pearson, M., Jereb, J., Frieden, T., Crawford, J., Davis, B., Dooley, S., Jarvis, W.; Ann. Intern. Med., 1992, 117, 191. 64. Riley, L.; Clin. Infect. Dis., 1993, 17, 442. 65. Ashtekar, D., Costa-Perira, R., Hagrajan K., Vishvamatham M., Bhatt A., Rittel, W.; Agents Chemother., 1993, 37, 183. 66. Wayne, L., Sramek, H.; Antimicrob. Agents Chemother., 1994, 38, 2054.

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67. (a) Esposito, D., Craigie, R.; Adv. Virus Res., 1999, 52, 319. (b) Asante-Appiah E., Skalka A.; Adv. Virus Res., 1999, 52, 351. (c). Pommier Y., Neamati N.; Adv. Virus Res., 1999, 52, 427. 68. (a) Hazuda, D., Felock, P., Witmar, M., Wolfe, A., Stillmock, K., Grobler, J., Espeseth, A., Gabryelski, L., Schleif W., Blau C., Miller M.; Science, 2000, 287, 646. (b) Selnick, H., Hazuda, D., Egbertson, M., Guare J., Wai, J., Young, S., Clark, D., Medina, J.; W09962513 (c) Toshio, F., Tomokazu, Y.; W099- JP1547. 69. Hazuda, D., Felock, P., Hastings, J., Pramanik, B., Wolfe, A.; J. Virol., 1997, 71, 7005. 70. Lee, H., Lee, J., Lee, S., Shin, Y., Jung, W., Kim, J., Park, K., Kim, K., Cho H., Ro S., Lee S., Jeong S., Choi, T., Chung H., Koh J.; Bioorg. Med. Chem. Lett., 2001, 11, 3069. 71. Padro, J., Tejedor, D., Santos-Exposito A., Garcya-Tellado F., Martin, V., Villar, J.; Bioorg. Med. Chem. Lett., 2005, 15, 2487. 72. Cohen, P.; The Enzymes; Academic Press: New York, 1986, 17, 461. 73. Cross, D., Alessi, R., Cohen, P., Jelkovich, M., Hemmings, B.; Nature, 1995, 378, 785. 74. Nikoulina, S., Ciaraldi, T., Mudaliar, S., Mohideen, P., Cartet, L., Henry, R.; Diabetes, 2000, 49, 263. 75. (a) Wagman, A., Johnson, K., Bussiere, D.; Curr. Pharm. Design, 2004, 10, 1.(b) Polychronopoulos, P., Magiatis, P., Skaltsounis, A., Myrianthopoulos, V., Mikros, E., Tarricone, A., Musacchio, A., Roe, S., Pearl, L., Leost, M., Greengard, P., Meijer, L.; J. Med. Chem., 2004, 47, 935. (c) Kunick, C., Lauenroth, K., Leost, M., Meijer, L., Lemcke, T.; Bioorg. Med. Chem. Lett., 14, 2004, 413. 76. Hers, I., Tavare, J., Denton R.; FEBS Lett., 1999, 460, 433. 77. Coghlan, M., Culbert, A., Cross, D., Corcoran, S., Yates, J., Pearce, N., Rausch, O., Murphy, G., Carter, P., Cox, L., Mills, D., Brown, M., Haigh, D., Ward, R., Smith, D., Murray, K., Reith, A., Holder, J.; Chem. Biol., 2000, 7, 793. 78. Kuo, G., Prouty, C., DeAngelis, A., Shen, L., O’Neill D., Shah, C., Connolly, P., Murray, W., Conway, B., Cheung, P., Westover, L., Xu, J., Look, R., Demarest, K., Emanuel, S., Middleton, S., Jolliffe, L., Beavers, M., Chen, X.; J. Med. Chem., 2003, 46, 4021.

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79. Engler, T., Henry, J., Malhotra, S., Cunningham, B., Furness, K., Brozinick, J., Burkholder, T., Clay, M., Clayton, J., Diefenbacher, C., Hawkins, E., Iversen, P., Li, Y., Lindstrom, T., Marquart, A., McLean, J., Mendel, D., Misener, E., Briere, D., O’Toole, J., Porter, W., Queener, S., Reel, J., Owens, R., Brier, R., Eessalu, T., Wagner, J., Campbell, R., Vaughn, R.; J. Med. Chem., 2004, 47, 3934. 80. WO0322833. 81. Katagi, T., Kataoka, H., Takahashi, K., Fujioka, T., Kunimoto, M., Yamaguchi, Y., Fujiwara, M., Inoi T.; Chem. Pharm. Bull., 1992, 40, 2419. 82. JP4662, 1967. 83. US3883516. 84. Hania, M.; Asian J. Chem., 2002, 14, 1074. 85. FR2204404; 86. Laurin, P., Ferroud, D., Klich, M., Dupuis-Hamelin, C., Mauvais, P., Lassaigne, P., Bonnefoy, A., Musicki, B.; Bioorg. Med. Chem. Lett., 1999, 9, 2079. 87. GR 19929086. 88. EP718299. 89. GR2640484. 90. Mizuno, A., Inomata, N., Miya, M., Kamei, T., Shibata, M., Tatsuoka, T., Yoshida, M., Takiguchi, C., Miyazaki, T., Chem. Pharm. Bull., 1999, 47, 246. 91. Mizuno, A., Ogata, A., Kamei, T., Shibata, M., Shimamoto, T., Hayashi, Y., Nakanishi, K., Takiguchi, C., Oka, N., Inomata N.; Chem. Pharm. Bull., 2000, 48, 623. 92. EP441349. 93. WO9303032. 94. Granados, R., Mauleon, D., Perez, M.; Ann. Quim. Ser. C, 1983, 79, 275 95. Baxter, A., Dixon, J., Ince F., Manners C., Teague S.; J. Med. Chem., 1993, 36(19), 2739.

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CCCHHHAAAPPPTTTEEERRR---333

Synthesis of 4-(dialkyl/alkyl)amino)-2-oxo- 2H-chromene-3-carbonitirles

Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

3.1 INRODUCTION

The chemistry of 4-hydroxycoumarin becomes important since the discovery of dicoumarol. A number of publications describing physiologically active 4- hydroxycoumarins have appeared in the literature. Phramalcogically earlier 4- hydrooxycoumarin are well established acting as anti-coagulant as well as rhodenticides(long acting anticoagulants). But in recent studies numerous potential caroinostatic, antitubercular, antibiotic, antiallergic, anthelmintic, central nervous system depressant, hypotensive, coronary dilator, antibacterial, antipsychotic, psychotropic and antifertility agents have been synthesized using 4-hydroxycoumarin. Coumarin derivatives possessing a 4-hydroxy group with a carbon at 3 position (I) of coumarin based structure possess diversified activity and are referred to as hydroxyl coumarins which are not present in coumarin itself.

(I) Coumarins owe their class name to ‘Coumarou’, the vernacular name of the tonka bean (Dipteryx odorata Willd., Fabaceae), from which coumarin itself was isolated in 1820.

Coumarin is classified as a member of the benzopyrone family of compounds, all of which consist of a benzene ring joined to a pyrone ring. The benzopyrones can be subdivided into the benzo-a-pyrones to which the coumarins belong and the benzo- g-pyrones, of which the flavonoids are principal members. Coumarins comprise a very large class of compounds found throughout the plant kingdom. They are found at high levels in some essential oils, particularly cinnamon bark oil (7,000 ppm), cassia leaf oil (up to 87,300 ppm) and lavender oil. Coumarin is also found in fruits (e.g. biilberry,cloudberry), green tea and other foods such as chicory. Most coumarins occur in higher plants, with the richest sources being the Rutaceae and Umbelliferae.

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Although distributed throughout all parts of the plant, the coumarins occur at the highest levels in the fruits, followed by the roots, stems and leaves. Environmental conditions and seasonal changes can influence the occurrence in diverse parts of the plant. Recently six new minor coumarins have been isolated from the fruits and the stem bark of Calophyllum dispar (Clusiaceae). The genus Calophyllum, which comprises 200 species, is widely distributed in the tropical rain forest where several species are used in folk medicine.

3.2 LITERATURE REVIEW

Coumarin and his derivatives were synthesized by many researchers using different methods. Perkin1 synthesized coumarin and then several methods are reported for the synthesis of 4-Hydroxy coumarins and their 4-Hydroxy substituted derivatives namely:

1 Anschutz method 2 2 Pauli Lockemann synthesis 3 3 Sonn's synthesis 4 4 Mentzer's synthesis 5 5 Robertson synthesis 6 6 Ziegler and Junek method 7 7 Garden's method 8 8 Shah, Bose and Shah's method 9 9 Kaneyuki method 10 10 Resplandy's method 11 11 Jain, Rohatagi and Sheshadri's method 12 12 Shah, Bhatt and Thakor's method 13

Shah et al. 9-13 have prepared 4-Hydroxy coumarin derivatives in good yield by condensation of different phenols with malonic acid in the presence of zinc chloride and phosphorous oxychloride. The method is useful as single step preparation of 4- Hydroxy coumarin derivatives substituted in benzenoid part.

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

Pechmann Coumarin Synthesis

Recently many researchers14-45 have reported synthetic strategies for 4- Hydroxy coumarin.

The employment of hydrophobic ionic liquids dramatically enhanced the activity of metal triflates in Friedel-Crafts alkenylations of aromatic compounds with various alkyl-and aryl-substitutedalkynes.46

Arylpropionic acid methyl esters having a MOM-protected hydroxy group at the ortho position underwent hydroarylation with various arylboronic acids in MeOH at ambient temperature in the presence of a catalytic amount of CuOAc, resulting in the formation of 4-arylcoumarins in high yields after the acidic workup.47

The basic ionic liquid 1-Butyl-3-methylimidazolium hydroxide, [bmim]OH, efficiently catalyzes the Knoevenagel condensation of various aliphatic and aromatic aldehydes and ketones with active methylenes at room temperature without requirement of any organic solvent. 48

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A facile, convenient, efficient and high yielding synthesis of a combinatorial library of 3-aroylcoumarins has been developed by the condensation of easily available aroylketene dithioacetals and 2-Hydroxybenzaldehydes in the presence of catalytic amount of piperidine in THF reflux.49

The ionic liquid 1-Butyl-3-methylimidazonium tetrafluoroborate [bmim]BF4 was used for Ethylenediammonium diacetate (EDDA)-catalyzed Knoevenagel condensation between aldehydes or ketones with active methylene compounds. Catalyst and solvent were recyclable.50

A new carbamoyl Baker-Venkataraman rearrangement allows a general synthesis of substituted 4-Hydroxycoumarins in good overall yields. Intermediate arylketones are efficiently prepared via a Directed ortho Metalation - Negishi cross coupling protocol from arylcarbamates. The overall sequence provides a regiospecific anionic Friedel-Crafts complement for the construction of ortho-acyl phenols and coumarins.51

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An Efficient and Practical Procedure for the Synthesis of 4-Substituted Coumarins.52

Coumarin syntheses via Pechmann condensation in Lewis acidic chloroaluminate ionicliquid.53

3.2.1 Reported synthetic strategy for the 4-arylaminocoumarin

The 4-arylamino coumarins are reported in literature.54 The reaction of various amines, such as primary aromatic, arylaliphatic and aliphatic amine with either 4- hydroxy or 4-chlorocoumarins results in the formation of N-substituted-4-amino coumarins. Apparently it is found that 4-aminocourmarin is prepared by direct method by removing acidic hydroxyl group with amino group in one step only, but alternate route is to convert the hydroxyl group into chloro group and then convert it into amino group by appropriate reagent for substitution (Scheme-2.1).

O O O O

OH HN R O O

R=H, Alkyl or Aryl Cl

The conversion of 4-hydroxy coumarin can also be afforded by a direct one step method using appropriate arylamine using solvents, without solvents under conventional heating or by using microwave assisted synthetic strategy. Anschutz54 reported the synthesis of 4-anilino coumarin during his pioneering work, by heating 4-hydroxy coumarin directly with aniline.

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Zagorevskii55 reported that the action of liquor ammonia on 4-chloro coumarin in the presence of copper powder exclusively afforded the 4-aminocoumarin. In another method, 4-chlorocoumarin when treated with concentrated ammonium hydroxide in dioxane for 40 hours at room temperature afforded 4-aminocoumarin (1) in 25% yield and o-hydroxyphenylpropionamide (2) (52% yield)56-58 due to opening of the lactone ring. However, only the desired 4-aminocoumarins were obtained in some cases.59-61

O O OH

NH2

NH2 O (1) 4-aminocoumarin (2) o-hydroxyphenylpropionamide

High electron density appears around the chlorine substituent and low electron density at the neighboring carbon atom at C4 is the reason that the chlorine atom is readily and quantitatively exchanged for nitrogen atom of amines and amino acids.62 It was also found that refluxing coumarin in an excess of amine, in the presence or absence of a solvent, yielded a mixture of the corresponding phenol and 4-arylamino coumarin.58 It was recently reported that refluxing coumarin in glacial acetic acid with an excess of primary amine prevented lactone ring opening with increased yield.63 Only the disadvantage of this method is long reaction time (10-20 h). The reaction of coumarins with secondary amines was reported to fail.63 All known methods require considerable excess of the amine, e.g. amine : coumarin molar ratios from 10:1 to 20:1 and, hence, large quantity of amine wasted. Ivanov 64 and co-worker have prepared 4- arylamino coumarin without any solvent in molar ratio of 1:1.2 under microwave irradiation with 90-98% yield.

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Checchi and Vettori65 prepared 4-aminocoumarin-3-sulphonamide and its derivatives. Sulphonation of 4-hydroxycoumarin in absence of any solvent, with an excess of chlorosulphonic acid yielded 3-sulphonic acid, which was converted to its potassium salt and on further chlorination with phosphorous oxychloride, afforded 4- chlorocoumarin sulphochloride. The treatment of either ammonia or primary aliphatic and aromatic amines led to the formation of 4-aminocoumarin-3-sulphonamide and its derivatives. 4-Arylaminocoumarins were prepared by treatment of an ethanolic solution of 4-hydroxycoumarin and o-aminobenzaldehyde under refluxe condition, which on further intramolecular cyclization afforded cromeno[4,3-b]quinoline.66 This gives way for another method for synthesis of 3, 4-fused system on coumarin nucleus.

Asherson et al. 67 heated dicoumarol and 4-hydroxycoumarin with aniline to yield 4-arylaminocoumarin. Which was further validated by Conlin et al.68 while they heated dicoumarol and 4-hydroxycoumarin with aniline, benzylamine and cyclohexylamine under reflux to yield corresponding anil of 4-hydroxycoumarin. Bhatt and Thakor 69 prepared 4-anilinocoumarins by direct condensation of 4- hydroxycoumarins with different amines, thus opening the single step route of such arylaminocoumarin derivatives. Joshi 70 and Berghaus 71 have also independently reported the synthesis of 4- amino benzopyrans as intermediate products during annelation. Reddy et al.72 carried out condensation reaction of 4-hydroxycoumarin and 2- aminothiophenol in dimethylsulfoxide. This cyclized product was desulfurized with Raney-Nickel to give 4-arylaminocoumarin.

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Hamdi et al. 73 reported that heating 1, 2-phenylenediamine with the 4- hydroxycoumarin in ethanol, two products were obtained, one was N-(2- aminophenyl)-3-hydroxy-3-(2-hydroxyphenyl) acrylamide (3) and another was 4-[(2- aminophenyl) amino]-2H-chromen-2-one (4). While 1, 4-phenylenediamine was refluxed in xylene with 4-hydroxycoumarin, it also gave two products, one was 4-[(4- aminophenyl) amino]-2H-chromen-2-one (5) and another was the dimer (6).

OH O O O

NH NH NH 2 OH 2 HN

(3) N-(2-aminophenyl)-3-hydroxy-3- (4) 4-((2-aminophenyl)amino)- (2-hydroxyphenyl)acrylamide 2H-chromen-2-one

O O O O O O HN HN NH

NH2 (5) 4-((4-aminophenyl)amino)- (6) Dimer 2H-chromen-2-one

3.2.2 3-CYANO COUMARIN

3-cyano-4-methyl coumarin also found their way into the the preparation of methine dyes.74 Variety of dyes was synthesized by reacting the 3-cyano-4-methyl coumarin with different dye intermediates. Very recently, 4-cyano couamrin derivatives found their application in photochemical polymerization, dye lasers and electroluminescent elements.75

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Hence Khellins were utilized as analgesic,hypnotics and antihistaminics. And in this study it was found that compounds i.e 3-cyano-5,8-dimethoxy-4-methyl- 6,7-furanocoumarin has more intense neuroplegic properties than khellin. Specifically these compounds relax the autonomous system i.e neurovegetative dystonias, depressive states such as anxiety, hyperemotional, hypernervousness. In combination with barbiturates, these derivatives are indicative in profound depressive states with loss of muscular tonus, obstinate insomnias, extraordinary pains (urethral lithiasis). In combination with antihistaminics they show gangliolegic power. being more precise, active against asthma, common and obstinate coughs, five day fevers of whooping cough. Moreover, another method for synthesis of 4-alkyl-3-cyano-coumarin derivatives were reported which deviates from the classical way. Alkylation of various 3-substituted coumarins were carried out and it was observed that cyano group at third position efficiently promoted 4-methylation76 and in continuation of this, alkylation was carried out by diazo ethene, 2-diazopropane, etc to give diverse 4- alkyl 3-cyano coumarins77

4-Methyl-3-(terazol-yl) coumarin is already known in the literature, where it was shown that these compounds did not show any antiallergic activity, but in the compounds of type (XX) showed substantial antiallergic activity. These compounds are preapred by reacting the substituted cyano coumarin with ammonium azide in inert organic solvent such as DMF at a temperature above room temperature. The ammonium azide is formed in-situ by reacting sodium azide with ammonium chloride.78

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

O-hydroxy acetophenones were transformed into 3-cyano-4-methylcoumarins by means of condensation with ethyl cyanoacetate in the presence of piperidine or ammonium acetate as a catalyst. Further, 4-styryl derivatives were obtained by condensation of the 3-cyano-4-methylcoumarins with different aromatic and heterocyclic aldehydes.79

Condensation of 4-chloro-2-oxo-2H-chromene-3-carbonitrile with selected heteroarylamines in acetonitrile contg. a catalytic amt. of triethylamine, followed by intramol. cyclization, gave the new coumarin derivatives.80

Reactions of 4-chloro-3-nitrocoumarin with a variety of nucleophiles produced a no. of novel substituted coumarins. Hard and borderline nucleophiles exclusively substitute chlorine in position 4, while soft nucleophiles substitute the nitro group in position 3 (except for iodide). This result of the nucleophilic substitution rationalized in terms of the HSAB model. 81

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

3.3 PHARMACOLOGY

Numerous biological activities have been associated with simple coumarin and its analogues. Among them, antimicrobial, antiviral, anticancer, enzyme inhibition, anti- inflammatory, antioxidant, anticoagulant and effect on central nervous system are most prominent. Coumarin nucleus possesses diversified biological activities that can be briefly summarized as under:

1 Antimicrobial and Molluscicidal 82-84 2 Antiviral 85-87 3 Anticancer 88-90 4 As Enzyme Inhibition 91-93 5 Antioxidant 94-97 6 Anti-inflammatory 98-100 7 Anticoagulant and Cardiovascular 101-103 8 Effect on Central Nervous System 104-105

4-Hydroxycoumarin is a versatile scaffold and is being consistently used as a building block in organic chemistry as well as in heterocyclic chemistry for the synthesis of different heterocyclic. The synthetic versatility of 4-Hydroxy coumarin has led to the extensive use of this compound in organic synthesis. 4-Hydroxy coumarin shows diversified chemical reactivity.

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

3.4 AIM OF CURRENT WORK

Various biological importances of Coumarin derivatives prompted us to synthesize some novel 3-cyano functionalized coumarin derivatives. To synthesize desired compounds we utilized 4-chloro-3-formyl coumarin. The current work is aimed for preparing novel 3-cyano coumarin derivatives from 3- formyl coumarin derivatives in presence of hydroxyl amine hydrochloride under the reaction conditions such that instead of formation of 2H-[1] benzopyran [3,4- d]isoxazoles-2-one. Since cyano coumarin is a privilege structure, the possibility of diverse pharmacological activities is expected from compounds synthesized in this chapter.

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

3.5 REACTION SCHEMES

3.5.1 PREPARATION OF 4-(DIALKYL/ALKYL)AMINO)-2-OXO-2H- CHROMENE-3-CARBONITIRLES

STEP-I: PREPARATION OF 4-CHLORO-3-FORMYL COUMARIN :

Reagents / Reaction Condition (a): DMF, POCl3, 0-5°C, 2 h, heat 60°C, 1 h.

STEP-II: PREPARATION OF 4-CHLORO-3-CYANO COUMARIN:

Reagents / Reaction Condition (b): hydroxyl amine hydrochloride, sodium acetate, acetic acid, 60°C, stirr.

STEP-III: PREPARATION OF 4-(DIALKYL/ALKYL)AMINO)-2-OXO-2H- CHROMENE-3-CARBONITIRLES

Reagents / Reaction Condition (c): DMF, K2CO3, 0-5°C, substituted primary/sec. amine.

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

3.6 PLAUSIBLE REACTION MECHANISM

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

3.7 EXPERIMENTAL

3.7.1 MATERIALS AND METHODS

NMR was determined in CDCl3/DMSO solution on a Bruker Ac 400 MHz spectrometer.

3.7.2 STEP-I: PREPARATION OF 4-CHLORO-3-FORMYL COUMARIN:

To a stirred mixture of 4-hydroxycoumarin (0.06 mol) in anhydrous DMF (0.6 mol) were added dropwise POCl3 (0.18 mol) at –10°C to –5°C. The reaction mixture was then stirred for 1 h at room temperature and heated and stirred for 2 h at 60°C. After the reaction completed, the mixture was poured onto crushed ice under vigorous stirring. After storing the mixture overnight at 0°C the pale yellow solid was collected by filtration and washed successively with Na2CO3 (5%) and water, and then was air– dried. Recrystallization from acetone gave 85% of 4-chloro-3-formyl coumarin as a pale yellow powder with m.p. 115–120 °C. (ARKIVOC, (6), 2001, 122-128)

3.7.2 STEP-II: PREPARATION OF 4-CHLORO-3-CYANO COUMARIN:

To a 20 mL solution of 4-chloro-3-formyl coumarin (0.01 mol) in glacial acetic acid was added sodium acetate (0.01mol) and hydroxyl amine hydrochloride (0.01 mol) and the solution was allowed to stirr at 60°C for 2 h. After completion of the reaction monitored the solid was filtered and washed with water (25 ml). Crystallization of compound from DMF:IPA (80:20) under 0-5°C yields 45% of 4- chloro-3-cyano coumarin as a light green crystals m.p. 198–200 °C. (Journal of Heterocyclic Chemistry 45(1), 2008, 295-297)

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3.7.3 STEP-III: PREPARATION OF 4-(DIALKYL/ALKYL)AMINO)-2-OXO- 2H-CHROMENE-3-CARBONITIRLES

4-chloro-3-cyano coumarin (0.01 mol) was dissolved in 10 mL DMF and allowed to stir between 0-5°C followed by addition of 2.0 g of K2CO3, and allowed to stir for 10 min. Primary/secondary amine (0.1 mol) was carefully added to the solution so that the temperature do not rise 10°C. Allow it to stir for 30 min and slowly raise to room temperature. After completion of the reaction, was poured into crushed ice, filtered and washed with water. Crystallization from chloroform gives 4- (dialkyl/alkyl)amino)-2-oxo-2H-chromene-3-carbonitirles. Yield 68-86%

The physical constants of newly synthesized compounds are given in Table No.1

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3.8 PHYSICAL DATA

Physical data of 4-(dialkyl/alkyl)amino)-2-oxo-2H-chromene-3-carbonitriles

Table-I Sr. Code R M.P. R No. f

1 BAJ-101 N 126-128 0.40

2 BAJ-102 CH3N N 134-136 0.43

3 BAJ-103 136-138 0.43 N N

4 BAJ-104 142-144 0.42 N N

H3C 5 BAJ-105 158-160 0.44 N N

6 BAJ-106 O N 144-146 0.43

7 BAJ-107 N-(CH(CH3)2)2 136-138 0.47

8 BAJ-108 N-(CH2CH3)2 148-150 0.42

9 BAJ-109 N-((CH2)3-CH3)2 162-164 0.44

10 BAJ-110 N-CH2-CH3 176-178 0.46

N 11 BAJ-111 144-146 0.50

CH3

12 BAJ-112 NH-CH3 142-144 0.48

N 13 BAJ-113 148-150 0.52

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

14 BAJ-114 N 164-166 0.44

15 BAJ-115 NH-(CH2)3-CH3 154-156 0.48

16 BAJ-116 NH-CH2-CH(CH3)2 148-150 0.38

17 BAJ-117 HN N 166-168 0.42

CH3 18 BAJ-118 148-150 0.48 N

Rf value was determined using solvent system = Ethyl Acetate : Hexane (3 : 2)

3.9 SPECTRAL DISCUSSION

3.9.1 IR SPECTRA

IR spectra of the synthesized compounds were recorded on Shimadzu FT-IR 8400 model using KBr pallet method. Various functional groups present were identified by characteristic frequency obtained for them. The characteristic bands of (-C≡N) were obtained for stretching at 2200-2100 cm-1. The stretching vibrations (–C-O-C-) group showed in the finger print region of 1100-1050 cm-1. (-C-N-) stretching was observed at 1400-1350 cm-1. Characteristic -1 band of (-CH2-) group was observed between1500-1450 cm . It gives aromatic (-C- H-) stretching frequencies between 3200-3000 and ring skeleton (-C=C-) stretching at 1500-1350 cm-1 C-H stretching frequencies for methyl and methylene group were obtained near 2950 - 2850 cm-1.

3.9.2 MASS SPECTRA

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3.9.3 1H NMR SPECTRA

1H NMR spectra of the synthesized compounds were recorded on Bruker

Avance II 400 spectrometer by making a solution of samples in CDCl3 solvent using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned. Numbers of protons and carbons identified from 1H NMR spectrum and their chemical shift (δ ppm) were in the agreement of the structure of the molecule. J values were calculated to identify o, m and p coupling. In some cases, aromatic protons were obtained as multiplet. Interpretation of representative spectra is discussed further in this chapter.

1.10.4 13C NMR SPECTRA

13C NMR spectra of the synthesized compounds were recorded on Bruker

Avance II 300 spectrometer by making a solution of samples in CDCl3 solvent using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned. Types of carbons identified from NMR spectrum and their chemical shift (δ ppm) were in the agreement of the structure of the molecule. Aliphatic carbon was observed between 15-25 δ ppm, methylene carbon was observed between 60-65 δ ppm and alkene carbon at 100-105 δ ppm. Aromatic carbon was observed between 115-140 δ ppm while aliphatic keto carbon was observed at 158-160 δ ppm. Carbon attached to hetero atom was observed at 155-157 δ ppm.

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

3.10 ANALYTICAL DATA

2-Oxo-4-(piperidin-1-yl)-2H-chromene-3-carbonitrile (BAJ-101) -1 Yield: 68% IR (cm ): 3126(aromatic -C-H stretching), 2839(aliphatic -CH2 stretching), 2198(-C-N stretching), 1710(-C=O stretching), 1599, 1545, 1516(-C=C- ring strain), 1448, 1354(-C-H bending), 1292(-C-N stretching tertiary amine), 1053(- 1 C-O-C stretching), H NMR (CDCl3) δ ppm: 6H, s (1.77), 3H,d (3.27-3.29 J=8.0 Hz), 2H, m (7.25-7.31), 1H,m (7.48-7.52), 1H, dd (7.75-7.77 J=8.0 HZ), 13C: 24.14, 26.48, 54.40, 104.87, 117.56, 118.68, 123.76, 125.34, 131.84, 145.74, 153.23, 159.57, + 161.85. MS: m/z = 254 (M ),; % Anal. Calcd. for C15H14N2O2: C, 70.85; H, 5.55; N, 11.02; O, 12.58.

4-(4-Methylpiperazin-1-yl)-2-oxo-2H-chromene-3-carbonitrile (BAJ-102) -1 Yield: 76% IR (cm ): 3190, 3161 (aromatic -C-H stretching), 2978 (aliphatic –CH- stretching), 2833 (aliphatic -CH2 stretching), 2152(-C-N stretching), 1718 (-C=O stretching), 1517(-C=C- ring strain), 1419,1354 (-C-H bending), 1323(-C-N stretching tertiary amine), 1012(-C-O-C stretching) MS= m/z = 269 (M+),; % Anal. Calcd. for

C15H15N3O2: C, 66.90; H, 5.61; N, 15.60; O, 11.88.

2-Oxo-4-(4-phenylpiperazin-1-yl)-2H-chromene-3-carbonitrile (BAJ-103) -1 Yield: 88% IR (cm ): 3043, 3021 (aromatic -C-H stretching), 2820 (Aliphatic -CH2 stretching), 2140(-C-N stretching), 1720(-C=O stretching), 1523(-C=C- ring strain), + 1419,1364 (-C-H bending), MS: m/z = 331 (M ),; % Anal. Calcd. for C20H17N3O2: C, 72.49; H, 5.17; N, 12.68; O, 9.66.

4-(4-Benzylpiperazin-1-yl)-2-oxo-2H-chromene-3-carbonitrile (BAJ-104) -1 Yield: 72% IR (cm ): 3051,3014 (aromatic -C-H stretching), 2879 (aliphatic -CH2 stretching), 2131(-C-N stretching), 1725(-C=O stretching), 1519(-C=C- ring strain), 1415,1346(-C-H bending), 1326(-C-N stretching tertiary amine), 1033(-C-O-C + stretching) MS: m/z = 345 (M ),; % Anal. Calcd. for C21H19N3O2: C, 73.03; H, 5.54; N, 12.17; O, 9.26.

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

4-(4-Ethylpiperazin-1-yl)-2-oxo-2H-chromene-3-carbonitrile (BAJ-105) -1 Yield : 69% IR (cm ): 3097, 3012 (aromatic -C-H stretching), 2978 (aliphatic –CH- stretching), 2901 (aliphatic -CH2 stretching), 2129(-C-N stretching), 1706(-C=O stretching), 1533(-C=C- ring strain), 1423,1340 (-C-H bending), 1354(-C-N stretching tertiary amine), 1029(-C-O-C stretching) MS: m/z = 283 (M+),; % Anal. Calcd. for

C14H14N2O2: C, 69.41; H, 5.82; N, 11.56; O, 13.21.

4-Morpholino-2-oxo-2H-chromene-3-carbonitrile (BAJ-106) -1 Yield : 86% IR (cm ): 3015, 3011 (aromatic -C-H stretching), 2945 (aliphatic –CH- stretching), 2879 (aliphatic -CH2 stretching), 2108(-C-N stretching), 1721(-C=O stretching), 1527(-C=C- ring strain), 1435 (-C-H bending), 1318(-C-N stretching tertiary amine), 1007 (-C-O-C stretching). MS: m/z = 256 (M+),; % Anal. Calcd. for

C14H12N2O3: C, 65.62; H, 4.72; N, 10.93; O, 18.73.

4-(Diisopropylamino)-2-oxo-2H-chromene-3-carbonitrile (BAJ-107) -1 Yield : 75% IR(cm ): 3115, 3041 (aromatic -C-H stretching), 2935 (aliphatic –CH- stretching), 2135(-C-N stretching), 1711 (-C=O stretching), 1560(-C=C- ring strain), 1425,1326 (-C-H bending), 1329(-C-N stretching tertiary amine), 1092 (-C-H bending), 1026(-C-O-C stretching) MS: m/z = 270 (M+),; % Anal. Calcd. for

C16H18N2O2: C, 71.09; H, 6.71; N, 10.36; O, 11.84.

4-(Diethylamino)-2-oxo-2H-chromene-3-carbonitrile (BAJ-108) -1 Yield: 78% IR (cm ): 3126, 3016(aromatic -C-H stretching), 2839(aliphatic -CH2 stretching), 2200(-C-N stretching), 1662(-C=O stretching), 1595, 1508(-C=C- ring strain), 1446, 1357(-C-H bending), 1325(-C-N stretching tertiary amine), 1097(-C-O- 1 C stretching), H NMR (CDCl3) δ ppm: 6H, t (1.17-1.20), 4H, q (3.47-3.53), 1H,m (7.23-7.27), 1H, d (7.32-7.34, J=8.0 Hz), 1H, m (7.49-7.53), 1H, m (7.70-7.72), 13C: 13.76, 47.47, 108.71, 117.48, 119.35, 123.73, 126.04, 131.94, 144.63, 153.34, 159.61, + 160.45. MS: m/z = 242 (M ),; % Anal. Calcd. for C14H14N2O2: C, 69.41; H, 5.82; N, 11.56; O, 13.21.

4-(Dibutylamino)-2-oxo-2H-chromene-3-carbonitrile (BAJ-109) -1 Yield : 78% IR (cm ): 3110, 3051 (aromatic -C-H stretching), 2978 (aliphatic -CH3 stretching), 2833(aliphatic -CH2 stretching), 2129(-C-N stretching), 1726(-C=O

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives stretching), 1522(-C=C- ring strain),1439,1364 (-C-H bending), 1314(-C-N stretching tertiary amine), 1017(-C-O-C stretching), MS: m/z = 298 (M+),; % Anal. Calcd. for

C18H22N2O2: C, 72.46; H, 7.43; N, 9.39; O, 10.72.

4-(Ethylamino)-2-oxo-2H-chromene-3-carbonitrile (BAJ-110) Yield : 69% IR (cm-1): 3435(-N-H stretching), 3190,3051 (aromatic -C-H stretching),

2978 (aliphatic -CH stretching) , 2843 (aliphatic -CH2 stretching), 2119(-C-N stretching), 1704 (-C=O stretching), 1616,1572 (-N-H bending), 1519(-C=C- ring strain),1439,1384 (-C-H bending), 1244, (-C-N stretching secondary amine), 1020(C- + O-C stretching), MS: m/z: 214 (M ),; % Anal. Calcd. for C12H10N2O2: C, 67.28; H, 4.71; N, 13.08; O, 14.94.

4-(2-Methylpiperidin-1-yl)-2-oxo-2H-chromene-3-carbonitrile (BAJ-111) -1 Yield: 82% IR (cm ): 3090, 3052 (aromatic -C-H stretching), 2988 (aliphatic –CH- stretching), 2853 (Aliphatic -CH2 stretching), 2116(-C-N stretching), 1726 (-C=O stretching), 1511(-C=C- ring strain), 1449,1374 (-C-H bending), 1311(-C-N stretching tertiary amine), 1081 (-C-H bending), 1011(-C-O-C stretching), MS: m/z = 268 + (M ),; % Anal. Calcd. for C16H16N2O2: C, 71.62; H, 6.01; N, 10.44; O, 11.93.

4-(Methylamino)-2-oxo-2H-chromene-3-carbonitrile (BAJ-112) Yield : 76% IR (cm-1): 3435(N-H stretching), 3190,3062 (aromatic -C-H stretching),

2998 (aliphatic –CH stretching), 2863 (aliphatic -CH2 stretching), 2126(-C-N stretching), 1706 (-C=O stretching) 1616,1542 (-N-H bending), 1231, (-C-N stretching secondary amine), 1024(-C-O-C stretching), MS: m/z = 200 (M+),; % Anal.

Calcd. for C11H8N2O2: C, 66.00; H, 4.03; N, 13.99; O, 15.98.

2-Oxo-4-(2-oxo-2,3-dihydro-1H-pyrrol-1-yl)-2H-chromene-3-carbonitrile (BAJ- 113) -1 Yield : 83% IR (cm ): 3090, 3072 (aromatic -C-H stretching), 2998 (aliphatic -CH stretching), 2873 (Aliphatic -CH2 stretching), 2115(-C-N stretching), 1742 (-C=O stretching), 1489,1372 (-C-H bending), 1008(-C-O-C stretching), MS: m/z = 252 + (M ),; % Anal. Calcd. for C14H8N2O3: C, 66.67; H, 3.20; N, 11.11; O, 19.03. 2-Oxo-4-(1H-pyrrol-1-yl)-2H-chromene-3-carbonitrile (BAJ-114)

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

Yield : 68% IR (cm-1): 3090,3072 (aromatic -C-H stretching), 2129(-C-N stretching),1714 (-C=O stretching), 1518 (-C=C- ring strain), 1332(-C-N stretching tertiary amine), 1258 (-C-H bending), 1031(-C-O-C stretching), MS: m/z = 236 (M+),;

% Anal. Calcd. for C14H8N2O2: C, 71.18; H, 3.41; N, 11.86; O, 13.55.

4-(Butylamino)-2-oxo-2H-chromene-3-carbonitrile (BAJ-115) Yield : 86% IR (cm-1): 3415(-N-H stretching), 3091, 3071 (aromatic -C-H stretching), 2978 (aliphatic -CH stretching), 2872 (aliphatic -CH2 stretching), 2133(- C-N stretching),1719 (-C=O stretching), 1616,1531 (-N-H bending), 1522(-C=C- ring strain), 1488,1371 (-C-H bending), 1244, (-C-N stretching secondary amine), 1019(- + C-O-C stretching), MS: m/z = 242 (M ),; % Anal. Calcd. for C14H14N2O2: C, 69.41; H, 5.82; N, 11.56; O, 13.21.

4-(Isobutylamino)-2-oxo-2H-chromene-3-carbonitrile (BAJ-116) Yield : 77% IR (cm-1): 3455(-N-H stretching), 3098, 3082 (aromatic -C-H stretching), 2988 (aliphatic -CH stretching), 2883 (aliphatic -CH2 stretching), 2123(- C-N stretching),1736 (-C=O stretching), 1636,1522 (-N-H bending), 1479,1382(-C-H bending), 1229, (-C-N stretching secondary amine), 1082(-C-H bending), 1012(-C-O- + C stretching), MS: m/z = 242 (M ),; % Anal. Calcd. for C14H14N2O2: C, 69.41; H, 5.82; N, 11.56; O, 13.21.

2-Oxo-4-(piperazin-1-yl)-2H-chromene-3-carbonitrile (BAJ-117) Yield : 89% IR (cm-1): 3435(-N-H stretching), 3080, 3062 (aromatic -C-H stretching), 2988 (aliphatic -CH stretching), 2883 (aliphatic -CH2 stretching), 2116(C- N stretching), 1722(-C=O stretching), 1636,1542 (-N-H bending), 1479,1382(-C-H bending), 1219(-C-N stretching secondary amine), 1027(-C-O-C stretching), MS: m/z + = 255 (M ),; % Anal. Calcd. for C14H13N3O2: C, 65.87; H, 5.13; N, 16.46; O, 12.54.

4-(Ethyl(phenyl)amino)-2-oxo-2H-chromene-3-carbonitrile (BAJ-118) -1 Yield : 82% IR (cm ): 3091, 3082 (aromatic -C-H stretching), 2997(aliphatic -CH stretching), 2871 (aliphatic -CH2 stretching), 2137(-C-N stretching), 1717(-C=O stretching), 1499,1371(-C-H bending), 1028(-C-O-C stretching), MS: m/z = 290 + (M ),; % Anal. Calcd. for C18H14N2O2: C, 74.47; H, 4.86; N, 9.65; O, 11.02.

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Chapter – 3 Synthesis of2-oxo-2H-chromene-3-carbonitirle derivatives

3.11 RESULTS AND DISCUSSION

Current chapter describes synthesis of 18 novel compounds characterized by various spectroscopic data. The reaction of 4-chloro-3-formyl coumarin with hydroxyl amine hydrochloride in presence of sodium acetate and acetic acid as a solvent afforded target synthon, which on further reaction with primary/secondary amines in presence of base yielded novel 3-cyano functionalize cumarin derivatives. The yield of these compounds varies from 68-86 %.

3.12 CONCLUSION

The synthetic methodology adopted led to considerable inprovement in the reaction product. The reaction product was obsereved as a 3-cyano derivative of coumarin. the reaction of 4-chloro-3-formyl coumarin with hydroxyl amine hdrochloride in the presence of sodium acetate and acetic acid afforded 4-chloro-3- cyano coumarin. The reaction is facile, easy to worup procedure and convinient to synthesize this class of molecules for biological interest.

However in presence of sodium acetate and ethanol under reflux condition the reaction of 4-chloro-3-formyl coumarin with hydroxyl amine hdrochloride yields 2H- [1] benzopyran [3,4-d] isoxazoles-2-one as reported in the prior art. 106

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3.13 REPRESENTATIVE SPECTRA

3.13.1 IR Spectrum of BAJ-101

3.13.2 MASS Spectrum of BAJ-101 O O

CN N

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3.13.3 1H NMR Spectrum of BAJ-101

3.13.4 Expanded 1H NMR Spectrum of BAJ-101

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3.13.5 13C NMR Spectrum of BAJ-101

3.13.6 DEPT Spectrum of BAJ-101

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3.13.7 IR Spectrum of BAJ-108

3.13.8 MASS Spectrum of BAJ-108

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3.13.9 1H NMR Spectrum of BAJ-108

O O

CN N

CH3 CH3

3.13.10 Expanded 1H NMR Spectrum of BAJ-108

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3.13.11 13C NMR Spectrum of BAJ-108

O O

CN N

CH3 CH3

3.13.12 DEPT Spectrum of BAJ-108

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3.14 REFERENCES :

1. (a) Perkin, W. H.; J. Chem. Soc., 1868, 21, 53; (b) Perkin, W. H.; Justus Liebigs Ann. Chem., 1868, 147, 229. 2. Anshutz, R.; Ber., 1903, 36, 465. 3. Pauly, H., Lokemann, K.; Ber., 1915, 48, 48. 4. Sonn, A.; Ber., 1917, 50, 1292. 5. Mentzer, C., Urbain, G.; Bull. Soc. Chem., 1944, 11, 171. 6. Robertson, A., Boyd, J.; J. Chem. Soc., 1948, 174. 7. Ziegler, E., Junek, H.; Monatshefte fuer Chemie, 1955, 86, 29. 8. Garden, J. F., Hayes, N. F., Thomso, R. H.; J. Chem. Soc., 1956, 3315. 9. Shah, V. R., Bose, J. L., Shah, R. C.; J. Org. Chem., 1960, 25, 677. 10. Kaneyuki, H.; Bull. Chem. Soc. Japan, 1962, 35, 579. 11. Resplandy, A.; Compat Rend., 1965, 260, 6479. 12. Jain, C., Rohtagi, K., Sheshadri, T. R.; Tet. Lett., 1966, 2701. 13. Shah, A., Bhatt, N., Thakor, V. M.; Curr. Sci., 1984, 53(24), 1289. 14. Sen, K., Bagchi, P.; J. Org. Chem., 1959, 24, 316. 15. Bose, J., Shah, R., Shah, V.; Chemistry & Industry, 1960, 623. 16. Shaikh, Y., Trivedi, K.; Ind. J. Chem., 1974, 12(12), 1262. 17. Barz, W., Schlepphorst, R., Laimer, J.; Phytochemistry, 1976, 15(1), 87. 18. Szabo, V., Borda, J.; Acta Chim. Acade. Scientia. Hung., 1977, 95(2-3), 333. 19. Szabo, V., Borda, J., Theisz, E.; Magy. Kemi. Folyoir., 1978, 84(3), 134. 20. Jerzmanowska, Z., Basinski, W., Zielinska, L.; Pol. J. Chem., 1980, 54(2), 383. 21. Ogawa, A., Kondo, K., Murai, S., Sonoda, N.; J. Chem. Soc., Chem. Commun., 1982, 21, 1283. 22. Basinski, W., Jerzmanowska, Z.; Pol. J. Chem., 1983, 57(4-5-6), 471. 23. Ogawa, A., Kambe, N., Murai, S., Sonoda, N.; Tetrahedron, 1985, 41(21), 4813. 24. Shobanaa, N., Shanmugam, P.; Ind. J. Chem., 1986, 25B(6), 658. 25. Chatterjea, J., Singh, K., Jha I., Prasad, Y., Shaw, S.; Ind. J. Chem., 1986, 25B(8), 796. 26. Mizuno, T., Nishiguchi, I., Hirashima, T., Ogawa, A., Kambe, N., Sonoda, N.; Synthesis, 1988, 3, 257.

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27. Shobana, N., Amirthavalli, M., Deepa, V., Shanmugam, P.; Ind. J. Chem., 1988, 27B(10), 965. 28. Parfenov, E., Savel'ev, V. L., Smirnov, L. D.; Khim. Geterotsikli. Soedin., 1989, 3, 423. 29. Pandey, G., Muralikrishna, C., Bhalerao, U.; Tetrahedron, 1989, 45(21), 6867. 30. Badran, M., El-Ansari, A., El-Meligie, S.; Rev. Roum. de Chim., 1990, 35(6), 777. 31. Nayak, S., Kadam, S., Banerji, A.; Synlett, 1993, 8, 581. 32. JP05255299. 33. JP05262756. 34. CN1101045. 35. Kalinin, A., Da Silva, A., Lopes, C., Lopes, R., Snieckus, V.; Tet. Lett., 1998, 39(28), 4995. 36. Sosnovskikh, V., Kutsenko, v., Ovsyannikov, I. S.; Russ. Chem. Bull., 2000, 49(3), 478. 37. Jung, J., Jung, Y., Park, O.; Synth. Commun., 2001, 31(8), 1195. 38. Long, X.; Jiangxi Shifan Daxue Xuebao, Ziran Kexueban, 2001, 25(3), 237. 39. Buzariashvili, M., Tsitsagi, M., Mikadze, I., Dzhaparidze, M., Dolidze, A.; Sakartvelos Mecnierebata Akademiis Macne, Kimiis Seria, 2003, 29(3-4), 242. 40. Ling, Y., Yang, X., Yang, M., Chen, W.; Huaxue Tongbao, 2004, 67(5), 355. 41. JP 2005097140. 42. Ganguly, N., Dutta, S., Datta, M.; Tet. Lett., 2006, 47(32), 5807. 43. Gebauer, M.; Bioorg. & Med. Chem., 2007, 15(6), 2414. 44. Park, S., Lee, J., Lee, K., Bull. Kore. Chem. Soc., 2007, 28(7), 1203. 45. CN101220016. 46. Song, C., Jung, D., Choung, S., Roh, E., Lee, S.; Angew. Chem., 2004, 116, 6309. 47. Yamamoto, Y., Kirai, N.; Org. Lett., 2008, 10, 5513. 48. Ranu, B., Jana, R.; Eur. J. Org. Chem., 2006, 3767. 49. Rao, H., Sivakumar, S.; J. Org. Chem., 2006, 71, 8715. 50. Su, C., Chen, Z., Zhen, Q.; Synthesis, 2003, 555. 51. Kalinin, A., Silva, A., Lopes, C., Lopes, R., Snieckus, V.; Tetrahedron. Lett., 1998, 39, 4995. 52. De, S., Gibbs, R.; Synthesis, 2005, 1231.

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53. Potdar, M., Mohile, S., Salunkhe, M.; Tet. Lett., 2001, 42, 9285. 54. Anschutz, R.; Liebigs Ann. Chem., 1909, 367, 204. 55. Zagorevskii, V. A.; Dudykina, N. V.; Zh. Org. Khim., 1962, 32, 2384. 56. Spalding, D. P.; Mosher, H. S.; Whitemore, F. C.; J. Am. Chem. Soc., 1950, 72, 5338. 57. Hismat, O. H.; Gohar, A. M.; Shahlash, M. R.; Ismail; I. Pharm. Acta. Helv., 1977, 52, 252. 58. Zagorevskii, V. A.; Dudykina, N. V. Zh.; Org. Khim., 1968, 4, 2041. 59. Zagoreviskii, V. A.; Savel’ev, V. L.; Meshcheriakova, L. M;. Khim.Geterotsikl. Soedin., 1970, 8, 1019. 60. Tabakovic, K.; Tabakovic, I.; Ajdini, N.; Leci, O.; Synthesis, 1987, 3, 308. 61. Harnisch, H.; Brack, A.; CA 1978, 88:106760e. 62. Mirko, K., Miladen, Albin, J.; Acta. Pharma. Jugosl., 1984, 34, 81. 63. Ivanov, I. C., Karaziosov, S. K., Manolov, I.; Arch. Pharm., 1991, 324, 61. 64. Ivanov, I. C.; Stoyanov, E. V.; Molecules, 2004, 9, 627. 65. Checchi, S.; Vettori, L. P.; Alberti, M. B.; Gazz. Chim. Ital., 1967, 97, 1749. 66. Tabakovic, K., Tabakovic, I., Trkovnik, M., Juric, A., Trinajstic, N.; J. Heterocyclic Chem., 1980, 17, 801. 67. Asherson, J. L., Bilgic, O., Young, D. W.; J. Chem. Soc., Perk. Trans., 1980, 2, 522. 68. Conlin, G. M., Gear, J. R.; J. Nat. Prod., 1993, 56, 1402. 69. Bhatt, N. S. Ph. D. Thesis, Saurashtra University, 1983. 70. Joshi, S. D., Sakhardance, V. D., Sheshadri, S., Ind. J. Chem., 1984, 23B, 206. 71. Berghaus, T. Ph. D. Thesis, University of Keli, 1989. 72. Reddy, S. B., Darbarwar, M., J. Ind. Chem. Soc., 1985, 62, 377. 73. Hamdi, M., Grech, O.; Sakellariou, R., Spéziale, V., J. Het. Chem., 1994, 31, 509. 74. GB672741. 75. US3176520. 76. Clinging, R., Dean, F. and Houghton, L.; J. Chem. Soc. (C)., 1970, 897. 77. Clinging, R., Dean, F., Houghton, L. and Park, B.; Tet. Lett., 1976, 15, 1227. 78. Buckle, Derek R., Cantello, Barrie C. C., Smith, Harry; GB1434645 1976. 79. Talapatra, S., Mandal, K. Biswas, K., Mandal, S. and Talapatra, B.; J. Ind. Chem. Soc., 1999, 76(11-12), 733.

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80. Dekic, S. V. et al; Chemical Papers, 2007, 61(3), 233. 81. Tabakovic, K. et al; Liebigs Annalen der Chemie, 1983, (11), 1901. 82. Kawase, M., Tanaka, T., Sohara, Y., Tan, S., Sakagami, H.; In vivo, 2003, 17, 509. 83. Zaha, Hazem, A.; New Microbio., 2002, 25, 213. 84. Gleye, G., Lewin, A., Laurens, C., Jullian and Loiseau, C.; J. Nat. Prod., 2003, 66, 323. 85. Bourinbaiar, S., Tan, X., Nagorny, R.; Acta Virol., 1993, 37, 241. 86. Zhao, H., Neamati, N., Pommier, Y., Burke, R., Jr.; Heterocycles, 1997, 45, 2277. 87. Vlientick, J., De Bruyne, T., Apers, S., Pieters, A.; Plant Med., 1998, 64, 97. 88. Edenharder, R., Tang, X.; Food Chem. Toxicol., 1997, 35, 357. 89. Ahmed,S., James, K., Owen, P., Patel, K.; Bioorg. & Med. Chem. Lett., 2002, 12, 1343. 90. Ho, T., Purohit, A., Vicker, N., Newman, P., Robinson, J., Leese, P., Ganeshapillai, D., Woo, L., Potter, L., Reed, J.; Biochem. Biophys. Res. Commun., 2003, 305, 909. 91. Sardari, S., Nishibe, S., Horita, K., Nikaido, T., Daneshtalab M.; Pharmazie, 1999, 54, 554. 92. Yang, B., Zhao, B., Zhang, K., Mack, P.; Biochem. Biophys. Res. Commun., 1999, 260, 682. 93. Wang, X., Ng, B.; Plant Med., 2001, 67, 669. 94. Costantino, L., Rastelli, G., Albasini, A.; Pharmazie, 1996, 51, 994. 95. Kaneko, T., Baba, N., Matsuo, M.; Cytotechnology, 2001, 35, 43 96. Fernandez-Puntero, B., Barroso, I., Idlesias, I., Benedi, J.; Bio. Pharm. Bull., 2001, 24, 777. 97. Lazarova, G., Kostova, I., Neychev, H.; Fitoterapia, 1993, 64, 134. 98. Delgado, G., Olivares, S., Chavez, M. I., Ramirez-Apan, T., Linares, E., Bye, R.; J. Nat. Prod., 2001, 64, 861. 99. Ghate, M., Manoher, D., Kulkarni, V., Shosbha, R., Kattimani, S.; Eur. J. Med. Chem., 2003, 38, 297. 100. Hadlipavlou-Litina, D.; J. Arzneim-Forsch./Drug Res., 2000, 50, 631. 101. Roma, G., Di Braccio, M., Carrieri, A., Grossi, G., Leoncini, G., Signorello, G., Carotti, A.; Bioorg. & Med. Chem., 2003, 11, 123.

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102. Chiou, F., Huang, L., Chen, F., Chen, C.; Planta Med., 2001, 67, 282. 103. Pignatello, R., Puleo, A., Giustolisi, S., Cuzzoccrea, S., Dugo, L., Caputi, P., Puglisi, G.; Drug Dev. Res., 2002, 57, 115. 104. Santana, L., Uriarte, E., Fall, Y., Teijeira, M., Teran, C., Garcia-Martinez, E., Tolf, R.; Eur. J. Med. Chem., 2002, 37, 503. 105. Gonzalez-Gomez, M., Santana, L., Uriarte, E., Brea, J., Villlazon, M., Loza, I., De Luca, M., Rivas, E., Montegero, Y., Fontela, A.; Bioorg. & Med. Chem. Lett., 2003, 13, 175. 106. Mulwad V.V., Hegde A.S.; Indian Journal of Chemistry, 2009, 48B, 1558.

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CCCHHHAAAPPPTTTEEERRR---444

Rapid synthesis of 5-(substituted)benzoyl- 4-(1-phenyl, 3(substituted)phenyl-1H- pyrazole-4-yl)-2,6-dimethyl-1,4- dihydropyridine-3-carbonitriles

Chapter – 4 Rapid synthesis of Dihydropyridine derivatives

4.1 INRODUCTION

Dihydropyridines are the largest and most studied class of drugs calcium channel blocker. In addition to their proven clinical utilities in cardiovascular medicine, dihydropyridines are employed extensively as biological tools for the study of voltage-activated calcium channel.

Many 1,4-dihydropyridine derivatives have been synthesized and developed as calcium channel antagonists which inhibit smooth and cardiac muscle contractions blocking the influx of Ca+2 through calcium channels and antihypertensive action .

4.2 LITERATURE REVIEW

Recently much effort has been expended to develop more efficient methods for the preparation of 1,4-DHPs such as using microwave1, metal triflates as catalyst2, 3 4 5 6 reaction in ionic liquid , p-TSA , HY-Zeolite , and HClO4 -SiO2 . 1,4-DHPs are synthesized by the Hantszch method, which involves cyclocondensation of aldehyde, β-ketoester, and ammonia either in acetic acid at room temperature or refluxing in alcohol for a long time.

Joshi et al.7 has used molecular iodine as a catalyst for the preparation of 1,4- dihydropyridine. Molecular iodine8-11 has attracted attention as an inexpensive, non toxic, readily available catalyst for various organic transformations to afford the corresponding products in excellent yields with high selectivity. It has been used as a mild Lewis acid in the dehydration of tertiaryalcohols to alkenes, in the formation of ethers, as well as β-keto enol ethers,12-14 for esterification,15 transesterification,16 acetylation9 and benzothiophene17 formation, but there are only a few reports about its use for the synthesis of 1,4-DHPs. Its use for the synthesis of 1,4-DHPs.18-19

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Xin Ying Zhang et al.20 developed an efficient and green method for the synthesis of 1, 4-dihydropyridine derivatives mediated in an ionic liquid,

[bmim][BF4], through a four-component condensation process of aldehydes, 1, 3- dione, Meldrum’s acid and ammonium acetate.

O O O O R CHO NH OAC O 4

[bmim][BF4]

O R

N O H

By this investigation they showed that not only aromatic aldehydes, but also heterocyclic and aliphatic aldehydes could undergo the above reaction effectively to afford the corresponding products in good yields.

Furthermore, 1, 3-cyclohexanedione and an acyclic 1, 3-dione, pentane-2, 4- dione were also tried in place of 5, 5-dimethyl-1, 3-cyclohexanedione for this multicomponent condensation process, respectively and it also gives the good results in preparation of DHP.

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Nandkishor et al.21 found that L-Proline has been found as an effective catalyst for the one pot synthesis of polyhydroquinoline derivatives via four component Hantzsch reaction. This method provides several advantages such as being environmentally benign, possessing high yields with increased variations of the substituents in the product and preparative simplicity.

CHO O O O R OC2H5 O

L-proline(Cat) NH4OAC Ethanol,reflux

O O

OC2H5 N H

Many MCR for synthesis of DHP and it’s aza analog dihydropyridines are revieved by several authors.22 The multicomponent reaction often affords the target compounds in good yields and this experimental method remains the most widely used protocol to access to 1,4-DHP differently substituted in position 4. Some modified procedures have later been proposed and they involve the use of preformed Knoevenagel adducts between the aldehyde and the keto ester or the use of preformed enaminoesters (represented in the E form to clarify the scheme).

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The Unsymmetric23-27 3-cyano-5-carboxy ester 1,4-diydrpyridine was prepared by condensation of aldehyde, 3-aminocrotononitrile with alkyl 3- aminocrotonate.

CHO NH 2 NH2 H C R 3 CN H3C COOR1

H NC COOR1

H3C N CH3 H

The other methods for the preparation28 of unsymmetric cyano 1,4- dihydropyridine are reported as under.

Two different routes of synthesis in single step are reported29 for 3-cyano ethoxycarbonyl-2,6-dimethyl-4-(2-trifluromethyl phenyl)-1,4-dihydropyridine.Firstly, the condensation of aldehyde with ethyl-3-aminocrotonate and 2-cyanoethyl-3- oxobutanoate. In another method, the condensation of ethyl-2-(2-triflouromethyl phenyl benzylidene ) acetoacetate was carried out with 2-cyanoethyl(2Z)-3-aminobut- 2-enoate.

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CHO NH2 CF3 O O CN H3C COOC2H5 O

CF3 H3CH2COOC COOCH2CH2CN

H3C N CH3 H

CF3 NH2 C2H5OOC H3C COOCH2CH2CN O

Bossert et al.30 have prepared anti-inflammatory agents such as 2-amino-3- benzoyl cyano-1,4-dihydropyridine.

Scoane et al.31 reported a facile method for synthesis of 3,5-dicyano-2,6- diphenyl-1,4-dihydropyridine(compound-1).When 3,5-dicyano-6-aminopyran was reacted with ammonium acetate in acetic acid gave the. While 3-cyano-5-carethoxy-6- aminopyran afforded to give fully aromatized pyridine.

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Berson et al.32 reported earlier for first time the synthesis of a quinoline containing unsymmetrical compound 4-(4-quinolyl)-2,6-dimethyl-3-carbethylxy-5- acetyl-1,4-dihydropyridne.

Bossert et al.33 also put in their efforts to preparing coronary dilator and

antihypertensive 1,4-dihydropyridines containing a quinoline group at C4 position. Ethyl 2-amino-4-(4-quinolyl)-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate have

been prepared by the cyclization of 1,3-cyclohexanedione with aldehyde and CH3-

CH2-CH2-C(NH)-NH2.

Other unsymmetric 2,6-diamino-4-(4-quinolyl)-1,4-dihydropyridine was synthesized by a different route.34

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Sachio et al.35 prepared antihypertensive 1,4-dihydropyridine containing a

benzo furazanyl moiety at C4 Position.

Ozbey et al.36 synthesized some 1,4-dihydropyridine derivatives containing the flavones ring system.

4.3 PHARMACOLOGY

1,4-DHPs posses different pharmacological activities such as antitumor,37 vasodilator,38 coronary vasodilator and cardiopathic,39 antimayocardiac ischemic, antiulcer,40 antiallergic,41 antiinflammatory42 and antiarrhythmic,43 PAF antagonist,44 Adenosine A3 receptor antagonist45 and MDR reversal activity.46 In particular, DHP-CA (calcium channel antagonist DHP) are extensively used for the treatment of hypertension,47 subarachnoid hemorrhage,48-49 myocardial infarction50-53 and stable54-55 and unstable angina56-57 even though recently their therapeutic efficacy in myocardial infarction and angina has been questioned.58 This class of compounds is also under clinical evaluation for the treatment of heart failure,59 ischemic brain damage62 nephropathies and atherosclerosis.61

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4.4 SOME DRUGS FROM 1,4-DIHYDROPYRIDINES NUCLEUS 37-41

4.5 PYRAZOLS : A VERSATILE SYNTHON

Pyrazole refers both to the class of simple aromatic ring organic compounds of the heterocyclic series characterized by a five-membered ring structure composed of three carbon atoms and two nitrogen atoms in adjacent positions and to the

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unsubstituted parent compound. Being so composed and having pharmacological effects on humans, they are classified as alkaloids, although they are rare in nature.

The synthesis of pyrazoles remains of great interest owing to the wide applications in pharmaceutical and agrochemical industry due to their herbicidal, fungicidal, insecticidal, analgesic, antipyretic and anti-inflammatory properties62-63. Some methods have been developed in recent years, though the most important method is the reaction between hydrazones and β-dicarbonyl compounds64 This reaction involves the double condensation of 1, 3-diketones or α, β-unsaturated ketones with hydrazine or its derivatives.65-66 However, the appealing generality of this method is somewhat vitiated by the severe reaction conditions or the multistep sequences usually required to access the starting materials.67 Thus, continuous efforts have been devoted to the development of more general and versatile synthetic methodologies for this class of compound.68

The application of Vilsmeier–Haack (VH) reagent (POCl3 / DMF) for formylation of a variety of both aromatic and heteroaromatic substrates is well documented.69 Besides this, the reagent has also been extensively used for effecting various chemical transformations from other classes of compounds. Many of these reactions have led to novel and convenient routes for the synthesis of various heterocyclic compounds.70 A notable example that finds significant application in heterocyclic chemistry is the synthesis of 4-formylpyrazoles from the double formylation of hydrazones with Vilsmeier-Haack (VH) reagent.71-72 These

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observations, coupled with the recent developments on the simple synthesis of pyrazole derivatives,73 especially 4-functionalized 1,3-diphenylpyrazoles as antibacterial, anti-inflammatory,74-75 antiparasitic76 and antidiabetic77 drugs, prompted chemistry research to undertake the synthesis of pyrazole-4-carboxldehyde derivatives using Vilsmeier-Haack (VH).78-79 The study is particularly aimed at developing a one-pot synthesis of pyrazole-4-carboxaldehyde oximes starting from acetophenone phenylhydrazones.

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4.6 AIM OF CURRENT WORK

The aim of current work was to prepare the dihydropyridine which have a

hybrid ‘motif’ where at C3- position possess a cyano group, while at C5 position various benzophenone groups are present. This will ultimately give structural and molecular diversity of unsymmetric nature.

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4.7 REACTION SCHEMES

4.7.1 PREPARATION OF PYRAZOLE ALDEHYDES:

STEP – 1

Reagents / Reaction Condition (a): Glacial acetic acid, Ethanol / Reflux, 5-6 hours.

STEP – 2

Reagents / Reaction Condition (b): DMF – POCl3 / 70-80°C, 5-6 hours.

4.7.2 PREPARATION OF ASYMMETRIC 1,4-DIHYDROPYRIDINES:

Reagents/ Reaction Condition (c): α-diketo comounds, Glacial Acetic acid / 60-70°C, 1 h

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4.8 PLAUSIBLE REACTION MECHANISM

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4.9 EXPERIMENTAL

4.9.1 MATERIALS AND METHODS

Melting points were determined in open capillary tubes and are uncorrected. Formation of the compounds was routinely checked by TLC on silica gel-G plates of 0.5 mm thickness and spots were located by iodine and UV. IR spectra were recorded in Shimadzu FT-IR-8400 instrument using KBr pellet method. Mass spectra were recorded on Shimadzu GC-MS-QP-2010 model using Direct Injection Probe 1 technique. H NMR was determined in CDCl3/DMSO solution on a Bruker Ac 400 MHz spectrometer. Elemental analysis of the all the synthesized compounds was carried out on Elemental Vario EL III Carlo Erba 1108 model and the results are in agreements with the structures assigned.

4.9.2 PREPARATION OF PYRAZOLE ALDEHYDE :

PREPARATION OF PYRAZOLE ALDEHYDE: GENERAL METHOD

STEP – 1: PREPARATON OF ACETOPHENONE PHENYL HYDRAZONES.

Appropriately substituted Acetophenone (0.1 mol) was dissolved in 50 ml of ethanol into 250 ml R.B.F. Phenyl hydrazine (0.1 mol) was added to above flask along with 3-4 drops of glacial acetic acid. The reaction mixture was stirred for 1 hours at room temperature. The progress and the completion of reaction was monitored by TLC using ethyl acetate : hexane (6 :4 ) as a mobile phase. After the completion of the reaction, the reaction mixture was kept to room temperature for 1 h and the crystalline product was filtered, washed with ethanol and dried at room temperature to give substituted acetone phenyl hydrazone in good yield which was pure enough to use as such for the next step. The Physical constants of newly synthesized compounds were compared with the standard data. 80

STEP – 2 PREPARATION OF PYRAZOLE ALDEHYDES

Dimethylformamide (0.32 mol) was transferred into 25 ml flat bottom flak. Phosphorous oxychloride (0.032 mol) was added under controlled rate under stirring so that temperature does not rise above 5°C. After complete addition, the mixture

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was raised to temperature and allow it to stir for 10-15 min. Freshly prepared acetophenone hydrazone 0.03 mole was added to above mixture and the content was heated on water bath for 5-6 hours. The progress and the completion of reaction was monitored by TLC using toluene: ethyl acetate (6: 4) as a mobile phase. After the completion of the reaction, mixture was cooled to room temperature and the content of the flask was poured on crushed ice to isolate the product. The separated product was filtered and washed with 1L cold water to remove complete acidity. It was further dried at 65°C and recrystallized from the mixture of DMF-Methanol to give crystalline pyrazole aldehyde in good yield. The Physical constants of newly synthesized compounds were compared with the standard data. 80

4.9.3 PREPARATION OF 5-CYANO-4-(1-PHENYL, 3(SUBSTITUTED) PHENYL-1H-PYRAZOL-4-YL)-2,6-DIMETHYL-1,4- DIHYDROPYRIDINE-3-CARBOXYLATES.

A mixture of pyrazole aldehyde (0.01 mol), and α-diketo compound (0.01

mol) in 10 ml glacial CH3COOH was added 3-amino crotononitrile (0.01 mol) under stirring condition at 60-70°C. Addition of 3-amino crotononitrile was performed at a very slow rate to avoid generation of unnecessary impurities. The reaction was continued for 1 h. The solid precipitates were filtered and washed with glacial acetic acid and further washed with hexane to yield desired compounds.

The Physical constants of newly synthesized compounds are given in Table No.1

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4.10 PHYSICAL DATA

4.10.1 Physical data of 5-Cyano-4-(1-phenyl, 3(Substituted)phenyl- 1H-pyrazol-4-yl)-2,6-dimethyl-1,4-dihydropyridine-3- carboxylates.

N N R O CN R1

H3C N CH3 H

TABLE – 1 Substitution Code MP Rf Value R R1 OC BAJ-501 C6H5 CH3 220-222 0.50 BAJ-502 C6H5 CH2-Cl 198-200 0.49 BAJ-503 C6H5 C6H5 178-200 0.47 BAJ-504 C6H5 4-F-C6H4 186-188 0.43 BAJ-505 C6H5 2,4-di-Cl- C6H3 202-204 0.44 BAJ-506 2-OMe-C6H4 CH3 166-168 0.45 BAJ-507 2-OMe-C6H4 CH2-Cl 208-210 0.44 BAJ-508 2-OMe-C6H4 C6H5 222-224 0.48 BAJ-509 2-OMe-C6H4 4-F-C6H4 238-240 0.43 BAJ-510 2-OMe-C6H4 2,4-di-Cl- C6H3 214-216 0.48 BAJ-511 2-OH- C6H5 CH3 228-230 0.45 BAJ-512 2-OH-C6H4 CH2-Cl 232-234 0.39 BAJ-513 2-OH-C6H4 C6H5 218-220 0.48 BAJ-514 2-OH-C6H4 4-F-C6H4 214-216 0.47 BAJ-515 2-OH-C6H4 2,4-di-Cl- C6H3 196-198 0.48

Rf value was determined using solvent system = Ethyl Acetate : Hexane (3 : 2)

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4.11 SPECTRAL DISCUSSION

4.11.1 IR SPECTRA

IR spectra of the synthesized compounds were recorded on Shimadzu FT-IR 8400 model using KBr method. Various functional groups present were identified by characteristic frequency obtained for them. The characteristic bands of -OH groups were obtained for streching at 3400- 3650 cm-1 and those for bending were obtained at 1050-1250 cm-1.The stretching vibrations N-H group showed in the region of 3200 to 3500 cm-1 with a deformation due to in plane bending at 1650-1580 cm-1. It gives aromatic C-H stretching frequencies between 3000-3200 cm-1 and bending vibration near 1300-1500 cm-1 respectively. C-H stretching frequencies for methyl and methylene group were obtained near 2950 cm-1 to 2850 cm-1. Characteristic frequency of C-N stretching showed near 2100-2300 cm-1 and bending vibration near 1250-1400 cm-1.

4.11.2 MASS SPECTRA

Mass spectra of the synthesized compounds were recorded on Shimadzu GC- MS QP-2010 model using direct injection probe technique. The molecular ion peak was found in agreement with molecular weight of the respective compound. Fragmentation pattern can be observed to be particular for these compounds and the characteristic peaks obtained for each compound.

4.11.3 1H NMR SPECTRA

1H NMR spectra of the synthesized compounds were recorded on Bruker

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protons were obtained as multiplet. Interpretation of representative spectra is discussed further in this chapter.

1.10.4 13C NMR SPECTRA

13C NMR spectra of the synthesized compounds were recorded on Bruker

Avance II 300 spectrometer by making a solution of samples in DMSO-d6 solvent using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned. Types of carbons identified from NMR spectrum and their chemical shift (δ ppm) were in the agreement of the structure of the molecule. Aliphatic carbon was observed between 15-25 δ ppm and aliphatic keto carbon at 30-40 δ ppm, while aliphatic carbon attached to hetero group was observed at 60-65 δ ppm. Aromatic carbon was observed between 115-140 δ ppm while aliphatic keto carbon was observed at 158-160 and aromatic keto carbon was observed at 190-195 δ ppm. Aromatic carbon attached to hetero atom was observed at 155-157 δ ppm.

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4.12 ANALYTICAL DATA

5-Acetyl-4-(1,3-diphenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4-dihydropyridine-3- carbonitrile (BAJ-501) Yield: 79% IR (cm-1): 3489,3367 (-N-H stretching), 3198(aromatic -C-H stretching), 2974 (aliphatic –CH stretching), 2875(-C-H stretching tertiary), 2260,2332(-C-N stretching), 1707(-C=O stretching), 1660-1587(-N-H bending), 1519,1435,1356(-C- H bending), 1291(-C-N stretching), MS: m/z = 394 (M+); % Anal. Calcd. for

C25H22N4O: C, 76.12; H, 5.62; N, 14.20; O, 4.06.

5-(2-Chloroacetyl)-4-(1,3-diphenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4- dihydropyridine-3-carbonitrile (BAJ-502) Yield : 79 % IR (cm-1): 3469,3307(-N-H stretching), 3191(aromatic -C-H stretching),

2984 (aliphatic -CH stretching), 2891(-C-H stretching tertiary), 2857(aliphatic -CH2 stretching), 2250,2312(-C-N stretching), 1727(-C=O stretching), 1650-1577(-N-H bending), 1509,1455, 1366(-CH bending), 1279(-C-N stretching), 749(-C-Cl + +2 stretching), MS: m/z = 428 (M ), 430 (M ) % Anal. Calcd. for C25H21ClN4O: C, 70.01; H, 4.93; Cl, 8.27; N, 13.06; O, 3.73.

5-Benzoyl-4-(1,3-diphenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4-dihydropyridine-3- carbonitrile (BAJ-503) Yield : 77 % IR (cm-1): 3459,3347(-N-H stretching), 3190(aromatic -C-H stretching), 2984 (aliphatic-CH stretching), 2884(-C-H stretching tertiary), 2262,2342(-C-N stretching), 1707(-C=O stretching), 1662-1587(-N-H bending), 1380(-C-H bending), + 1288(-C-N stretching), MS: m/z = 456 (M ); % Anal. Calcd. for C30H24N4O: C, 78.92; H, 5.30; N, 12.27; O, 3.50.

4-(1,3-Diphenyl-1H-pyrazol-4-yl)-5-(4-fluorobenzoyl)-2,6-dimethyl-1,4- dihydropyridine-3-carbonitrile (BAJ-504) Yield : 87 % IR (cm-1): 3459,3347(-N-H stretching), 3188(aromatic -C-H stretching),

2954 (aliphatic -CH stretching), 2894(-C-H stretching tertiary), 2240,2342 (-C-N stretching), 1717(-C=O stretching), 1669-1581 (-N-H bending), 1396 (-C-H bending) ,1272 (-C-N stretching), 1107(-C-F stretching) 689 (monosubstituted) MS: m/z = 474

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+ +1 (M ), 475 (M ); % Anal. Calcd. for C30H23FN4O: C, 75.93; H, 4.89; F, 4.00; N, 11.81; O, 3.37.

5-(2,4-Dichlorobenzoyl)-4-(1,3-diphenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4- dihydropyridine-3-carbonitrile (BAJ-505) Yield : 81 % IR (cm-1): 3489,3367 (-N-H stretching), 3198 (aromatic -C-H stretching), 2974 (aliphatic –CH stretching), 2888(-C-H stretching tertiary), 2260,2332 (-C-N stretching), 1707(-C=O stretching), 1660-1587 (-N-H bending), 1356 (-C-H bending) , 1282(-C-N stretching), 801(-C-Cl stretching), 744 + +2 (disubstituted), MS: m/z = 525 (M ), 527 (M ); % Anal. Calcd. for C30H22Cl2N4O: C, 68.58; H, 4.22; Cl, 13.49; N, 10.66; O, 3.05.

5-Acetyl-4-(3-(2-methoxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4- dihydropyridine-3-carbonitrile (BAJ-506) Yield : 83 % IR (cm-1): 3253(-N-H stretching), 3132(aromatic -C-H stretching), 2918

(aliphatic -CH stretching), 2841(-C-H stretching tertiary), 2196(-C-N stretching), 1712(-C=O stretching), 1658-1537(-N-H bending), 1597, 1537(-C=C- ring strain), 1454,1411,1350 (-C-H bending), 1247(-C-N stretching), 1159(-C-O-C stretching), 1 692(monosubstituted), H NMR (DMSO-d6) δ ppm: 6H, s (1.84), 3H, s (3.34), 3H, s (3.72), 2H, m (7.08-6.99), 1H, s (4.33), 2H, m (7.08-6.98), 1H, d (7.24-7.21, J=7.2), 1H, t (7.32-7.27), 1H, t (7.42-7.38), 2H, t (7.52-7.48), 2H. d (7.89-7.87, J=7.8), 1H, s (8.52), 1H, s (9.11), 13C: 17.62, 31.37, 55.03, 82.08, 110.65, 117.74, 119.39, 121.63, 126.05, 126.94, 129.53, 129.94, 131.61, 139.37, 146.14, 149.19, 157.00, 191.10. + MS: m/z = 424 (M ); % Anal. Calcd. for C26H24N4O2: C, 73.56; H, 5.70; N, 13.20; O, 7.54.

5-(2-Chloroacetyl)-4-(3-(2-methoxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6- dimethyl-1,4-dihydropyridine-3-carbonitrile (BAJ-507) Yield : 79 % IR (cm-1): 3479,3368(-N-H stretching), 3192(aromatic -C-H stretching),

2934 (aliphatic -CH3 stretching), 2889(-C-H stretching tertiary), 2843 (aliphatic -CH2 stretching), 2261,2331 (-C-N stretching), 1717(-C=O), 1661-1577 (-N-H bending), 1518,1445,1354 (-C-H bending), 1283(-C-N stretching), 1187(-C-O-C stretching), 722(-C-Cl stretching), 689(monosubstituted), MS: m/z = 458. (M+), 460 (M+2); %

Anal. Calcd. for C26H23ClN4O2: C, 68.04; H, 5.05; Cl, 7.72; N, 12.21; O, 6.97.

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5-Benzoyl-4-(3-(2-methoxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4- dihydropyridine-3-carbonitrile (BAJ-508) Yield : 69 % IR (cm-1): 3509,3357(-N-H stretching), 3190(aromatic -C-H

stretching), 2984 (aliphatic -CH3 stretching), 2898(-CH stretching tertiary), 2261,2330 (-C-N stretching), 1717(-C=O stretching), 1661-1589 (-N-H bending), 1518,1434,1354 (-C-H bending),`1281 (-C-N stretching), 1193(-C-O-C stretching), + 689 (monosubstituted), MS: m/z = 486 (M ); % Anal. Calcd. for C31H26N4O2: C, 76.52; H, 5.39; N, 11.51; O, 6.58.

5-(4-Fluorobenzoyl)-4-(3-(2-methoxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6- dimethyl-1,4-dihydropyridine-3-carbonitrile (BAJ-509) Yield : 78 % IR (cm-1): 3479,3368(-N-H stretching), 3188(aromatic -C-H

stretching), 2978 (aliphatic -CH stretching), 2887 (-CH stretching tertiary), 2250,2342 (-C-N stretching), 1727(-C=O stretching), 1665-1581 (-N-H bending), 1529,1425,1346 (-C-H bending) ,1272 (-C-N streching), 1186(-C-O-C stretching), 1109(-C-F stretching), 689 (monosubstituted), MS: m/z = 504 (M+), 505 (M+1); %

Anal. Calcd. for C31H25FN4O2: C, 73.79; H, 4.99; F, 3.77; N, 11.10; O, 6.34.

5-(2,4-Dichlorobenzoyl)-4-(3-(2-methoxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6- dimethyl-1,4-dihydropyridine-3-carbonitrile) (BAJ-510) Yield : 79 % IR (cm-1): 3489,3389(-N-H stretching), 3159(Aromatic -C-H

stretching), 2979 (aliphatic -CH stretching), 2879(-CH stretching tertiary), 2288,2332 (-C-N stretching), 1707(-C=O stretching), 1679-1569 (-N-H bending), 1529,1455,1356 (-C-H bending) ,1282 (-C-N stretching), 1180(-C-O-C stretching), 791(-C-Cl stretching), 749 (disubstituted), 687 (monosubstituted), MS: m/z = 555 + +2 (M ), 557 (M ); % Anal. Calcd. for C31H24Cl2N4O2: C, 67.03; H, 4.36; Cl, 12.77; N, 10.09; O, 5.76.

5-Acetyl-4-(3-(2-hydroxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4- dihydropyridine-3-carbonitrile (BAJ-511) Yield : 89 % IR (cm-1): 3612(O-H stretching), 3583,3566(-N-H stretching),

3198(aromatic -C-H stretching), 2974 (aliphatic -CH stretching), 2897(-C-H stretching tertiary), 2245(-C-N stretching), 1707(-C=O stretching), 1660-1587 (-N-H bending), 1519,1435,1356 (-C-H bending), 1240 (-C-N stretching), 1107(O-H bending),

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1 744(disubstituted), 688(monosubstituted), H NMR (DMSO-d6) δ ppm: 6H, s (1.86), 3H, s (3.38), 1H, s (4.48), 1H, t( 6.87-6.84, J=7.2), 1H. d (6.93-6.91, J=7.8), 2H, t (7.23-7.19), 1H, t (7.32-7.27), 2H, t (7.93-7.87), 1H , s (8.51), 1H d (9.14-9.10), 1H, s (9.61), 13C: 17.67, 21.11, 26.82, 31.28, 82.02, 107.47, 115.28, 115.77, 116.25, 117.75, 118.38, 119.56, 119.79, 126.04, 126.32, 127.00, 128.00, 128.88, 129.56, 129.91, 131.10, 131.45, 138.62, 139.40, 154.78, 146.34, 149.74, 154.85, 155.48, 193.18. MS: + m/z = 410 (M ); % Anal. Calcd. for C25H22N4O2: C, 73.15; H, 5.40; N, 13.65; O, 7.80.

5-(2-Chloroacetyl)-4-(3-(2-hydroxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6- dimethyl-1,4-dihydropyridine-3-carbonitrile (BAJ-512) Yield : 81 % IR (cm-1): 3609(O-H stretching), 3459,3377 (-N-H stretching), 3058

(aromatic -C-H stretching), 2976 (aliphatic -C-H stretching), 2899(-C-H stretching

tertiary), 2828(aliphatic -CH2 stretching), 2261,2322 (-C-N stretching), 1727(-C=O stretching), 1689-1588 (-N-H bending), 1539,1435,1343(-C-H bending), 1273(-C-N bending), 1234,1101(O-H bending), 738(disubstituted), 679 (monosubstituted), MS: + +2 m/z = 444 (M ), 446 (M ); % Anal. Calcd. for C25H21ClN4O2 C, 67.49; H, 4.76; Cl, 7.97; N, 12.59; O, 7.19.

5-Benzoyl-4-(3-(2-hydroxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4- dihydropyridine-3-carbonitrile (BAJ-513) Yield : 78 % IR (cm-1): 3611(OH stretching), 3479,3347(-N-H stretching),

3108(romatic -C-H stretching), 2974(aliphatic -C-H stretching), 2897(-C-H stretching tertiary), 2260,2332(-C-N stretching), 1707(-C=O stretching), 1660-1587 (-N-H bending), 1519,1435,1356 (-C-H bending) ,1282(-C-N stretching), 1240,1107(-OH bending), 788(-C-Cl stretching), 744 (disubstituted), 688(monosubstituted, MS: m/z = + 472 (M ); % Anal. Calcd. for C30H24N4O2: C, 76.25; H, 5.12; N, 11.86; O, 6.77.

5-(4-Fluorobenzoyl)-4-(3-(2-hydroxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6- dimethyl-1,4-dihydropyridine-3-carbonitrile (BAJ-514) Yield : 76 % IR (cm-1): 3595(O-H stretching), 3489,3357(-N-H stretching),

3118(aromatic -C-H stretching), 2984 (aliphatic -C-H stretching), 2887 (-C-H stretching tertiary), 2261,2342 (-C-N stretching), 1717(-C=O stretching), 1661-1581 (-N-H bending), 1518,1445,1346 (-C-H bending) ,1281 (-C-N stretching), 1241,1117 (-OH bending), 1108(-C-F stretching). 689 (monosubstituted), MS: m/z = 490 (M+),

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+1 491 (M ); % Anal. Calcd. for C30H23FN4O2: C, 73.46; H, 4.73; F, 3.87; N, 11.42; O, 6.52. 5-(2,4-Dichlorobenzoyl)-4-(3-(2-hydroxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6- dimethyl-1,4-dihydropyridine-3-carbonitrile (BAJ-515) Yield : 89 % IR (cm-1): 3593(O-H stretching), 3419,3307(-N-H stretching),

3101(aromatic -C-H stretching), 2970 (aliphatic -C-H stretching), 2890 (-C-H stretching tertiary), 2261,2322 (-C-N stretching), 1707(-C=O stretching), 1669- 1586(-N-H bending), 1509,1425,1326(-C-H bending) ,1283(-C-N bending), 1241,1117(-OH bending),799(-C-Cl stretching), 745(disubstituted), 685 (monosubstituted), MS: m/z = 541 (M+), 543 (M+2); % Anal. Calcd. for

C30H22Cl2N4O2: C, 66.55; H, 4.10; Cl, 13.10; N, 10.35; O, 5.91.

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4.13 RESULTS AND DISCUSSION

This chapter deals with the preparation of asymmetric dihydropyridine by three component reaction by modifying general conventional methodologies. Ethyl acetoacetate/Methyl acetoacetate, methyl 3-aminocrotonate and Pyrazole aldehydes have been employed to synthesize these DHPs. Under normal conditions, the DHPs were prepared by refluxing the aldehydes, 3-aminocrotononitrile and Methyl acetyoacetate/Ethyl acetoacetate more than 10 hrs.

4.14 CONCLUSION

In this chapter, along with yield optimization of the 1,4-Dihydropyridines, simple, easy and fast method was adopted. Exploration of unreported compounds and their biological activity was the aim behind the work done in this chapter.

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4.15 REPRESENTATIVE SPECTRA

4.15.1 IR Spectrum of BAJ-506

4.15.2 MASS Spectrum of BAJ-506

O N N

O CN H3C H C N CH 3 H 3

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4.15.3 1H NMR Spectrum of BAJ-506

4.15.4 Expanded 1H NMR Spectrum of BAJ-506

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4.15.5 13C NMR Spectrum of BAJ-506

O N N

O CN H3C H C N CH 3 H 3

4.15.6 IR Spectrum of BAJ-511

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4.15.7 MASS Spectrum of BAJ-511

HO N N

O CN H3C H C N CH 3 H 3

4.15.8 1H NMR Spectrum of BAJ-511

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4.15.9 Expanded 1H NMR Spectrum of BAJ-511

4.15.10 13C NMR Spectrum of BAJ-511

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4.16 REFERENCES

1. (a) Khadikar, B. M., Gaikar, V. G., Chitnavis, A. A.; Tet. Lett., 1995, 36, 8083- 8086. (b) Ohberg, L., West man, J.; Synlett. 2001, 1296-1298. (c) Agarwal, A., Chauhan, P. M. S.; Tetrahedron Lett., 2005, 46, 1345. 2. Wang, L., Sheng, J., Zhang, L., Han, J. W., Fan, Z. Y., Tian, H., Qian, C. T. Tetrahedron, 2005, 61, 1539. 3. (a) Ji, S. J., Jiang, Z. Q., Lu, J., Loh, T. P.; Synlett 2004, 831. (b) Sridhar, R., Perumal, P. T.; Tetrahedron, 2005, 61, 2465. 4. Cherkupally, S. R., Mekala, R.; Chem. Pharm. Bull., 2008, 56, 1002. 5. Das, B., Ravikant, B., Ramu, R., Rao, B. V.; Chem. Pharm. Bull., 2006, 54, 1044. 6. Maheswara, M., Siddaiah, V., Damu, G. L. V., Rao, C. V.; Arkivoc, 2006, ii, 201. 7. Akbari, j. d., Tala, S. D. Dhaduk, M. F., Joshi, H. S.; Arkivoc, 2008, (XII) 126. 8. Sun, J., Dong, Y., Wang, X., Wang, S., Hu, Y.; J. Org. Chem., 2004, 69, 8932. 9. Phukan, P.; Tetrahedron Lett., 2004, 45, 4785. 10. Ke, B., Qin, Y., He, Q., Huang, Z., Wang, F.; Tetrahedron Lett., 2005, 46, 1751. 11. Banik, B. K., Fernandez, M., Alvarez, C.; Tetrahedron Lett., 2005, 46, 2479. 12. Kartha, K. P. R.; Tetrahedron Lett., 1986, 27, 3415. 13. Jenner, G.; Tetrahedron Lett., 1988, 29, 2445. 14. Bhosale, R. S., Bhosale, S. V., Bhosale, S. V., Wang, T., Zubaidha, P. K.; Tetrahedron Lett., 2004, 45, 7187. 15. Ramalinga, K., Vijayalakshmi, P., Kaimal, T. N. B.; Tetrahedron Lett., 2002, 43, 879. 16. Chavan, S. P., Kale, R. R., Shivasankar, K., Chandake, S. I., Benjamin, S. B.; Synthesis, 2003, 2695. 17. Hessian, K. O., Flynn, B. L.; Org. Lett., 2003, 5, 4377. 18. Ko, S., Sastry, M. N. V., Lin, C., Yao, C. F.; Tetrahedron Lett., 2005, 46, 5771. 19. Zolfigol, M. A., Saleh, P., Khorramabadi-Zad, A., Shayegh, M. J.; Mol. Catal., 2007, 261, 88. 20. Xin Ying ZHANG., Yan Zhen LI., Xue Sen FAN., Gui Rong QU., Xue Yuan HU., Jian Ji WANG., Chinese Chemical Letters 2006, Vol. 17, No. 2, pp 150.

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21. Nandkishor, N. Karade, Vishnu, Budhewara, H., Sandeep, V. Shinde, Wamanrao, N., Jadhav,; Letters in Organic Chemistry, 2007, 4, 16. 22. Hantzsch, A. Condensationprodukte aus Aldehydammoniak und Ketoniartigen Verbindungen. Ber. 1881, 14, 1637. 23. GR122524. 24. ZA7707702. 25. Kastron, V. V., Duburs, G., vitolis, R., Skrastins, I., Kimenis, A.; Khim-Farm. Zh., 1985, 19(5), 545; 1977 C.A., 104, 88392d 1986. 26. Wehinger, E., Bossert, F., Franckowiak, G., Meyer, H.; Ger. Offen. 1978, 2, 658, 804; 1978 C.A., 89, 109133j. 27. Cozzi, P., Briatico, G., Giudici, D., Rossi, A., Salle, E. D.; Med. Chem.Res., 1996, 6:9, 611-17. 28. Ohsumi, K., Ohishi, K., Mrinaga, Y., Nakagawa, R., Suga, Y., Sekiyama, T., Akiyama, Y., Tsuji, T., Tsuruo, T.; Chem. Pharm. Bul., 1995, 43 (5), 818. 29. GR2847236. 30. GR2845530. 31. Seoane, C., Soto, J. L., Quinterio, M.; Rev. R. Acad. Cienc. Exaetas, Eis Nat. Madrid, 1979, 73 (4), 614. 32. Berson, J, A., Brown, E.; J. Amer. Chem. Soc., 1955, 77, 444. 33. (a) Meyer, H., Bossert, F., Vater, W., Stoepl, K.; C.A., 84, 164639a.. (b) US3515642 (c) US3935223. 34. US3988458. 35. JP61186380. 36. Ozbey, S., Kendi, E.; J. Heterocyclic Chem., 1998, 35, 1485. 37. Cooper, K., Fray, M. J., Parry, M. J.; J. Med. Chem., 1992, 35, 3115. 38. Zidermane, A.; Duburs, G.; Zilbere, A.; PSR Zinat. Akad. Vestic 4, 77 1971; C.A., 1991 75, 47266, 9. 39. Wehinger, W. E., Horst, M., Andres, K., Yoshiharu.; C.A., 1987, 107. 40. EP197448. 41. EP 220653. 42. EP272693. 43. US4758669. 44. JP235909.

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45. Copper, K., Fray M. J, Parry. M. J., Richardson, K., Steele J.; Med. Chem., 1992, 35, 3115-3129. 46. Van Rhee A. M., Jiang J. L., Melman N., Olah M. E., Stiles G. L., Jacobson K. A.; J. Med. Chem., 1996, 39, 2980. 47. Shah, A., Gaveriya, H., Mothashi, N., Kawase, M.; Anticancer Res., 2000, 20, 373. 48. Singer, T. P., Kearney, E. B.; Advan. Enzymol., 1964, 15, 79. 49. Haneeon, L.; Calcium antagonists: An overview. Am. Heart J., 1991, 122, 308. 50. Pickard, J. D.; Murray, G. D.; Illingworth, R.; Shaw, M. D. M.; Teasdale, G. M.; Foy, P. M.; Humphrey, P. R. D.; Lang, D. A.; Nelson, R.; Richards, P.; Sinar, J.; Bailey, S.; Brit. Med. J., 1989, 298, 636-642. 51. Buchbeit, J. M., Tremoulet, M.; Neurosurg., 1988, 23,154-167. 52. Loogna, E., Sylven, C., Groth, T., Mogensen, L.; Eur. Heart J., 1986, 6,114- 119. 53. SPRINT Study Group. The secondary prevention re-infarction Israeli nifedipine trial (SPRINT) 11: design and methods, results. Eur. Heart. J., 1988 9(Suppl. I), 360 A. 54. Myocardial Infraction Study Group. Secondary prevention of ischemic heart disease: a long term controlled lidoflazine study. Acta Cardiol., 1979, 34 (Suppl. 24), 7-46. 55. Subramanian, V. B.; Excepta Medica (Amsterdam), 1983, 97. 56. Mueller, H. S., Chahine, R. A.; Am. J. Med., 1981, 71, 645. 57. Antman, E., Muller, J., Goldberg, S., McAlpin, R., Rubenfire, M., Tabatznik, B., Liang, C.-S., Heupler F., Achuff, S., Reichek, N., Geltman, E., Kerin, N. Z., Neff, R. K., Braunwald, E. N.; Engl. J. Med., 1980, 302, 1269. 58. Ginsburg, R., Lamb, I. H., schroeder, J. S., Harrison, M.H., Harrison, D.C.; Am. Heart. J., 1982, 103, 44. 59. Held, P. H., Yueuf, S., Furberg, C. D.; Br. Med. J., 1989, 299, 1187. 60. Reicher-Reiss, H., Baruch, E.; Drugs Today, 1991, 42, 3, 343. 61. Gelmere, H. J., Henneric, N.; Stroke, 1990, 21 (SUPI.IV), 81-IV 84. 62. Triggle, D. J.; Drugs Today, 1991, 27, 3, 147. 63. Elguero, J.; In Comprehensive Heterocyclic Chemistry, Vol. 5; A. Katritzky,Ed.; Pergamon Press: Oxford, 1984, 277.

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64. Elguero, J.; In Comprehensive Heterocyclic Chemistry, Vol. 5; I. Shintai, Ed.; Elsevier: Oxford, 1986, 3. 65. Kost , A., and Grandberg ,G.; Adv. Heterocycl. Chem., 1966, 6, 347. 66. Wiley, R., and Hexner, P, E.; Org. Synth., 1951, 31, 43. 67. (a) Falorni, M., Giacomelli, G., and Spanedda, A, M.; Tetrahedron: Asymmetry, 1998, 9, 3039. (b) L. D. Luca, M. Falorni, G. Giacomelli and A. Oorcheddu; Tet. Lett., 1999, 40, 8701. (c) B. C. Bishop, K. M. J. Brands, A. D. Gibb and D. J. Kennedy; Synthesis, 2004, 43. 68. Elguero, J.; In Compreensive Heterocyclic Chemistry, Vol. 3; A. R. Katritzky; C. W. Rees; E. F. V. Scriven, Eds.; Pergamon Press: Oxford, 1996, 1. 69. (a) Almirante, N., Cerri, A ., Fedrizzi, G., Marazzi G., and Santagostino, M.; Tet. Lett., 1998, 39, 3287. (b) S. Cacchi, G. Fabrizi and A. Carangio; Synlett, 1997, 959. (c) A. J. Nunn and F. Rowell; J. Chem. Soc., 1975, 2435. (d) D. E. Kizer, R. B. Miller and M. J. Kurth; Tet. Lett., 1999, 40, 3535. (e) L. N. Jungheim; Tet. Lett., 1989, 30, 1889. (f) P. Grosche, A. Holtzel, T. B. Walk, A. W. Trautwein and G. Jung, Synthesis, 1999, 1961. (g) X.-j. Wang, J. Tan, K. Grozinger, R. Betageri, T. Kirrane and J. R. Proudfoot; Tet. Lett., 2000, 41, 5321. 70. Jones, G., and Stanforth , S.; Org. React., 2001, 49, 1. 71. Meth-Cohn, O., and Tarnowski, B., Adv. Heterocycl. Chem., 1982, 31, 207; P. T. Perumal; Ind. J. Het. Chem., 2001, 11, 1; Majo, V. J., Perumal, P. T.; J. Org. Chem., 1998, 63, 7136. 72. Kira, M,. Abdel-Rahman, M., Gadalla, K .; Tet. Lett., 1969, 10, 109. 73. Prakash, O., Kumar, R., Bhardwaj, V., Sharma, P.; Heterocycl. Commun., 2003, 9(5), 515; Kumar, A., Prakash, O., Kinger, M., Singh, S. P.; Can. J. Chem., (in press); Selvi, S., Perumal, P. T.; Ind. J. Chem., 2002, 41B, 1887. 74. El-Emary, T., Bakhite, E.; Pharmazie, 1999, 54, 106. 75. Bratenko,M,. Vovk,M., Sydorchuk,I.; Farm. Zh., 1999, 68. 76. CS275459 B219920219. 77. Rathelot, P., Azas, N., El-Kashef, H., Delmas, F., Giorgio, C., David,P and Maldonado,V.; Eur. J. Med. Chem., 2002, 37, 671. 78. Cottineau, B., Toto, P., Marot, C., Pipaud, A., Chenault, J.; Biorg. & Med. Chem. Lett., 2002, 12, 2105. 79. Luca, L., Giacomelli, G., Masala, S., Porcheddu, A.; Synlett, 2004, 13, 2299.

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80. Thakrar S,; Ph.D. Thesis, Saurashtra University 2010.

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CCCHHHAAAPPPTTTEEERRR---555

Synthesis of 8-((substituted)amino)-10- methylchromeno[3,4-b] thieno[2,3- e][1,4]diazepin-6(12H)-ones

Chapter – 5 Synthesis of diazepine derivatives

5.1 INRODUCTION

The clinical importance and commercial success associated with the 1,4- benzodiazepine class of central nervous system (CNS)-active agents and the utility of 1,4-diazepines as peptidomimetic scaffolds have led to their recognition by the medicinal chemistry community as privileged structures. This ring system has demonstrated considerable utility in drug design, with derivatives demonstrating a wide range of biological activities. On the other hand, examples of the serendipitous discovery of new drugs based on an almost random screening of chemicals synthesized in the laboratory are striking. Since 1960, when chlordiazepoxide (Librium) entered in the market, efforts to discover new biologically active compounds with limited side effects in benzodiazepines are going on which are reflected by the important number of publication focused in this subject.1-5 Among all types of benzodiazepines (1,2-,1,3-, 1,4-, 1,5-, 2,3-, & 2,4- ) only 1,4- and 1,5-benodiazepines have found wide applications in medicines, during one of the most important classes of the therapeutic agents with wide spread biological activities6 including hypnotics, sedatives, anxiolytics and antianxiety etc., effect range from their well-documented anticonvulsive or tranquilizing properties, through pesticidal7 or antitumor8 action and to their more recently described peptidomimetic activity. 9 The cyclic amidines represent an important functional group in medicinal chemistry and can be found in many natural products or FDA-approved drugs, e.g. the antipsychotic clozapine and loxapine. Moreover, substituted amidines are useful intermediates in the synthesis of many heterocyclic compounds. 10 The most common and convergent strategies for amidine synthesis are based on the addition of amines to activated amide intermediates, e.g. imido ester, 11 imidoyl chloride12 or o-triflated imidate. 13 In 1969, Fryer et al reported a one-step method for the preparation of cyclic amidines from amides using titanium tetrachloride complex. 14 Clozapine was originally synthesized in 1960s by Sandoz-Wander Ltd based upon a structural similarity to the tricyclic antidepressant, but it showed unexpectedly a high antipsychotic activity that lead to a new class of antipsychotic drug useful in the treatment of schizophrenia.

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Diazepine derivatives constitute an important class of heterocyclic compounds which possess a wide range of therapeutic and pharmacological properties. Derivatives of benzodiazepines are widely used as anticonvulsant, antianxiety, analgesic, sedative, anti-depressive, and hypnotic agents15, 16 as well as anti- inflammatory agents. 17 In the last decade, the area of biological interest of 1,5- benzodiazepines has been extended to several diseases such as cancer, viral infection and cardiovascular disorders.18,19 In addition, 1,5-benzodiazepines are key intermediates for the synthesis of various fused ring systems such as triazolo-, oxadiazolo-, oxazino- or furanobenzodiazepines.20-23 Besides, benzodiazepine derivatives are also of commercial importance as dyes for acrylic fibers in photography. 24 From the standpoint of biological activity, fused heteroaromatic systems are often of much greater interest than the constituent monocyclic compounds. Recently, the thienodiazepine system has been studied extensively. They have been tested clinically as an anxiolytic and hypnotic.25 Recently, there has been considerable interest in hetero[1,4]diazepine with an additional ring fused to the seven-member ring, structurally analogues to the a-face-fused 1,4-benzodiazepines.

5.2 LITERATURE REVIEW

Sayed et al 26 has synthesized 5,7-dimethyl-5H-benzo[2,3][1,4]diazepino[6,5- c]quinolin-6(13H)-one (2) by the reaction of 3-acetyl-4-hydroxy-1-methylquinolin- 2(1H)-one and o-phenylenediamine.

Ghosh and Khan27 report the reaction of 3-formylchromones with o- phenylenediamine. The benzo[b]chromeno[2,3-e][1,4]diazepin-13(6H)-one was prepared in two step as shown below.

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o-Phenylenediamine undergoes 1,2-addition to the nitrile functions of 3- nitrilechromone to form intermediate amidines, which on further cyclization and subsequent air oxidation afforded 6-amino-7-oxo-7H-[l]benzopyrano[2,3-b]- [1,5]benzocliazepines. 28

Reaction of 4-chloro-3-(l-chlorovinyl)-6-methyl-2H-pyran-2-one with o-

phenylenediamine gives pyranobenzodiazepine in the presence of Et3N in 98% EtOH under reflux condition. 29

4-hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-one were treated with carbon disulfide in dimethyl sulfoxide in the presence of a catalytic amount of pyridine to yield the novel condensed benzodiazepin-2-thione. In this case, ring closure exclusively proceeded by intramolecular nucleophilic attack of the double bond of the pyrone moiety on the isothiocyanate intermediate and not through nitrogen, which would give benzoimidazole-2-thione derivatives.30

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The reaction 3-nitro-4-chlorocoumarin with anthranilic acid gave 3-nitro-4-(2-

carboxyphenyl)coumarin. Which was hydrogenated in alcohol over Pd/BaSO4 under the usual conditions to give 3-amino-4-(2-carboxyphenyl)coumarin; the latter was cyclized to benzo[e]chromeno[3,4-b][1,4]diazepin-6(13H)-one by refluxing in concentrated hydrochloric or glacial acetic acid.31

The reaction of 3-nitro-4-chlorocoumarin with anthranilic acid was used to synthesize N-(3-nitro-4-coumarinyl)-anthranilic acid, from which, through the acid chloride, obtained a number of amides, which were reduced to N-(3-amino-4- coumarinyl)anthranilic acid amides. The latter are cyclized under the influence of hydrochloric acid to 6,7,8,13-tetrahydro[l]benzopyrano-[4,3-b][l,4]benzodiazepine- 6,8-dione (Scheme 5.7), which was also obtained from N-(3-amino-4- coumarinyl)anthranilic acid by its thermolysis or treatment with hydrochloric acid.32

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O O H N O O O O 2 SOCl + 2

NO2 HO2C NO2 NO2 Cl HN HN

HO2C ClOC

HNRR1 O O O O O O NH H+ NH2 [H] NO HN O HN 2 HN

R1RNOC R RNOC Scheme 5.7 1

4-Azido-3-coumarincarbaldehydes are useful starting materials for syntheses of a variety of 3,4-disubstituted coumarins as well as heterocyclic [c]-fused coumarins, e. g. isoxazoles, pyrazoles and 1,5-diazepines, under mild conditions.33 The reaction of 4-Azido-3-coumarincarbaldehydes with o-phenylenediamine to afford benzo[e]chromeno[3,4-b][1,4]diazepin-6(13H)-one.

4-Chloro-3-coumarincarbaldehyde or 4-azido-3-coumarincarbaldehyde were converted into 1,4-benzodiazepines by nucleophilic substitution with diamines and subsequent cyclization with good yields.34

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O O O O O O H2N DMF NaN Y 3 + acetone- POCl3 H N X R water 2 OH Cl O N3 O DMF

H N 2 Y O O

H2N X R

Et3N/EtOH, reflux HN N R=H, CH3; X=C, N; Y=C, N X Y R

The 6-formylfurocoumarin derivative were reacted with o-phenylene-diamine in EtOH and the resulting imines which underwent intramolecular cyclocondensation reaction using acetic acid gave the corresponding benzodiazepine derivative.35

O O O O O O H2N O O O O O O AcOH + reflux CHO H2N O OH O OH N O HN N

(25) H N 2

5.3 REPORTED SYNTHETIC STRATEGIES FOR THE PIPERAZINYL DERIVETIVES OF BENZO- AND THIENODIAZEPINES

Different synthetic pathways are generally used to convert lactams or aminoesters into the amidine group. The diazepines were synthesized by reacting the corresponding diazepinone derivatives with an appropriate amine in the presence of 36 TiCl4 and anisole according to modified Fryer’s method. The diazepinones were also converted into the corresponding thiones that after reaction with an amine gave the desired amidine. Oxa- and thiazepine analogues were obtained following another approach. Lactams were treated with an excess of phosphorus oxychloride in

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refluxing toluene to give iminochlorides which directly reacted with an excess of the desire amine to give the appropriate amidines.

The tricyclic ring has been differently modified during 1980s. Replacement of the central heteroatom NH was made by classical isosteric substitution (O, S, and

CH2). This modification generates products with a strong central depressant activity. 37, 38 The partial replacement of nitrogen atom in the seven member rings provided a potent alternative to clozapine, fluperlapine.39 The compound was synthesized from the amide converted to the iminochloride which was treated with N-methylpiperazine. An alternative approach was an intramolecular dehydration of amide.

Bioisoteric replacement of the distal benzene rings is largely intended to improve the pharmacological profile and/or the bioavailability, but mainly to reduce toxicological problems. Thiophene rings have been incorporated in different tricyclic nuclei. The introduction of a heterocycle in the tricyclic structure generally provides

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two chemical series according to the lactam position (-[1,4]- and -[1,5]- analogues). In these series of compounds, a lot of benzodiazepine analogues have mainly been synthesized.

Thieno[2,3-b][1,5]benzodiazepines Such compounds were synthesized by condensation of halogenonitrobenzene (2-fluoronitro, 2,5-difluoronitrobenzene) with thiophene amino ester (ethyl-2-amino- 5-methylthiophene-3-carboxylate). The nitroanilinothiophene derivative was then reduced by catalytic hydrogenation to the orthophenelynediamine analogue. The cyclization by means of NaH in DMSO afforded the corresponding lactam which was condensed with N-methylpiperazine using Fryer's Procedure (Scheme 5.13).36

Thieno[3,4-b][1,4]benzodiazepines The key intermediate thieno[3,4-b][1,4]benzodiazepinone was prepared using several methods.40 The anthranilamide was obtained from an appropriate substituted isatoic anhydride and 3-amino-4-ethoxytheophene. The enol ether-like moiety is acid labile and subject to nucleophilic attack. Indeed, intramolecular cyclization was operated with polyphosphoric acid. The amidine was obtained following the Fryer's procedure.36 Thieno[3,4-b][1,4]benzodiaze-pines have a neuroleptic/antidepressant mixed action profile similar to their [1,5] isomer41 but are less potent.

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O O H H N R N R 2 DMSO O + S S N O EtO H NH2EtO

PPA N O N MNP R NH R N TiCl4, toluene N S H N S H

Thieno[3,4-b][1,5]benzodiazepines The appropriate substituted o-phenylenediamine was condensed with methyl tetrahydro-4-oxo-thiophene-3-carboxylate to give the tetrahydrolactam which was then oxidized in the corresponding aromatic thiophene derivative and then compound reacted with N-methylpiprazine.41 Corresponding benzoxa- and benzothiazepines were also described as potent antispychotics. 41,42 Amidines were prepared using pentachloride in toluene to form the iminochlorides which reacted with N- methylpiperazine.

Tieno[3,2-b][1,5]- and Tieno[3,2-b][1,4]benzodiazepines The synthetic pathways for preparing these derivatives were similar to those used for thieno[2,3-b][1,5] isomer. Aminothiophene carboxylate was treated with halogenonitrobenzene in DMSO in the presence of potassium carbonate as basic

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catalyst.43 The activity determined by hypothermia in mice, conditioned avoidance response procedure and catalepsy was increased when the phenyl ring was substituted with a halogen at position 7. Glamkowski et al synthesized the tetracyclic 1H-quinobenzodiazepines bearing a pendant N-methylpiperazine substituent.43 The key step involves a Bischler- Napieralski type cyclization of the ureas. This was achieved by refluxing in phosphorus oxychloride to affect a cyclodehydration to form the seven-membered central ring.

Another tetracyclic bezo[c]pyrrolo[1,2,3-ef][1,5]benzodiazepine derivatives were synthesized by cyclization of (7-aminoindolin-1-yl)benzamide or benzoic acid. The resulting tetracyclic lactams were treated with N-methylpiperazine in the presence of titanium tetrachloride to provide piperazinyl derivatives which were tested for potential antipsychotic activity.44

Tetracyclic 12-Amino-6H-[1]benzothieno[2,3-b][1,5]benzodiazepine (46) derivatives have been synthesized as shown below and they have been tested for the treatment of schizophrenia, Alzheimer’s disease.45

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NO R NO2 NC 2 H 1 F K2CO3 N R + H2N R1 R DMF S S NC

1. NaSO3,DMF 2. Conc. HCl, N MeOH NH N N 2 N NMP R R1 R R1 N N H S H S

R=H,Cl,F,CH,CF,etc R1 =H,Cl,F,CH3,OCH3,etc 3 3

A series of 4-(4-methylpiperazin-1-yl)theino[2,3-b][1,5]benzoxazepines has been synthesized from 4-bromo-2-methylthiiophene or ethyl 2-amino-4,5-dimethyl-3- thiophencarboxylate. Preparation of the key intermediate thieno[2,3-b][1,5]benzoxa- zepine-4(5H)-ones were carried out by treatment of 2-bromo-N-(2-hydroxyphenyl)-3- thiophencarboxamides with potassium carbonate in DMSO.46

NH2 EtOOC OH O OH + pyridine R R Br toluene N S H S Br

K2CO3 DMSO N

N H O N N 1. POCl3 R R 2. NMP O O S S

R=H,Cl,CH,OCH,etc 3 3 The benzodiazepines olanzapine and clozapine are nowadays manufactured by a three-step process with a final yield below 50%. An approach to environmentally- friendly intensive processes consists in the development of multifunctional solid catalyst able to catalyze multistep reactions. The bifunctional metal acid solid catalyst was prepared and able to carry out hydrogenation-cyclisation-amination reactions in a

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cascade process. The catalytic system was illustrated for the synthesis of these important antipsychotics.47

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5.4 PHARMACOLOGY

The synthesis of a new class of anellated 1,4-benzodiazepines with anti-psychotic activity was exemplified by preparation of 10-fluoro-3-methy1-7-(2-thieny1)- 1,2,3,4,4a,5-hexahydropyrazino[1,2-a][1,4]benzodiazepine. The influence of variations of the fluoro-substitution pattern and variations of the fused ring system on the biological activity of the structural analogues was evaluated.48

3-Acetyl coumarins when allowed react with isatin gave corresponding 3-(3’- hydroxy-2’-oxoindolo)acetylcoumarins, which on dehydration afforded the corresponding α,β-unsaturated ketones. Which on Cyclocondensation with substituted o-phenylenediamines resulted in novel 4-(2-oxo-2H-chromen-3-yl)-1,5-dihydro spiro[benzo[b][1,4]diazepine-2,3'-indolin]-2'-one. Structures of all the compounds have been screened for their antimicrobial activity and antianxiety activity in mice.49

Nakanishi et al 50 reports the synthesis and pharmacological activity of tetrazolo, oxadiazolo and imidazothienodiazepines derivatives. Some of them were found as minor tranquilizers.

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X X X

R1 R1 R1

R2 N R2 N R2 N S S S N N N N N N N N O O R =H,alkyl,etc;R =H,alkyl,etc;X=H,CF, halogen, alkoxy group 1 2 3

Tricyclic ring systems possessing a dibenzo structure joined to a central seven- membered heterocyclic ring with a basic side chain frequently show effects on the central nervous system. During the last 40 years, a number of dibenzepines have been introduced. Some of these are powerful antipsychotic agents: clotiapine, metiapine, and loxapine are classical neuroleptics showing a similar pattern of pharmacological activities to the phenothiazines, while amoxapine has antidepressant properties and perlapine is a hypnotic agent.37 Clozapine is an exception, since it was the first example of a new class of tricyclic neuroleptics with a novel activity pattern, producing minimal extrapyramidal side effects (EPS) in man.51 Fluperlapine is the newest drug with a clozapine-like activity: it is in clinical trial and resembles clozapine qualitatively and quantitatively.39,52

Chakrabarti et al [53] described the synthesis and pharmacological evaluation of a series of pyrazolo[l,5]benzodiazepines. Some of the 4-piperazinyl-2,10-dihydro- pyrazolo[3,4-b][1,5]benzodiazepine derivatives demonstrated potent anxiolytic activity. Compounds and were more active than the clinically effective anxiolytic chlordiazepoxide in releasing conflict-suppressed behavior. This study shows a

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dissociation of the anxiolytic and antidopaminergic activities found in the thieno- and dibenzodiazepine derivatives flumezapine and clozapine, respectively.

Chakrabarti et al 54 described the synthesis and biological evalution of [1,2,3]triazolo[4,5-b][1,5], imidazolo[4,5-b][1,5], and pyrido[2,3-b] [1,5]benzodiazepines in their another paper. The antidopaminergic and anticholinergic activities of the compounds have been examined by the respective in vitro [3H]spiperone and [3H]QNB receptor binding assay. The neuroleptic potential has been further evaluated in terms of their ability to produce hypothermia and catalepsy in mice and a conditioned avoidance response in rats. Only compounds from the triazolobenzodiazepine series show antipsychotic potential. The lack of activity in the imidazolo- and pyridobenzodiazepine series indicates that the basicity of the heteroarene moiety may be determinant for activity.

Novel 4-arylpiperazin-1-yl-substituted 2,3-dihydro-1H-1,4- and 1H-1,5-benzo diazepines and their aza-analogues were synthesized as debenzoclozapine derivatives for evaluation as potential D4-ligands. While Ki values of some of the compounds

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came within the range of clozapine, they showed an impressively greater selectivity over other dopamine receptor subtypes, especially D2. For the most promising

compounds, intrinsic activity and binding properties to serotonin 5-HT1A and 5-HT2 were also determined.55

N N N N N Cl N N N N N N H H N H

N N

N N N N

N N H

Sasikumar et al 56 reports the acylated and aroylated hydrazinoclozapines

which were found highly potent dopamine D1 antagonists that show remarkable selectivity over other dopamine receptors. The most potent compound in this series

was the 2,6-dimethoxybenzhydrazide 33 with a D1 Ki of 1.6 nM and 212-fold

selectivity over D2 receptor.

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5.5 SOME DRUGS FROM DIAZEPINE NUCLEUS 37-56

N H C O N N 3 O N Cl S N HN N H C N S S 3 Cl Br Bentazepam Ciclotizolam Anxiolytic GABAA receptor agonist Clotiazepam N Anxiolytic N H3C N S N N N N N C2H5 S N Br N N N N N Cl Cl Cl N S S Etizolam H Short-term treatment of Brotizolam Olanzapine Clotiapine anxiety or panic attacks Sedetive-Hypnotic atypical antipsychotic atypical antipsychotic

N N N N O N N N S N HO Cl N S N Cl H Metitepine Clozapine S antagonist at various serotonin atypical antipsychotic & dopamine reseptor used in the treatment Quetiapine used as anantipsychotic of schizophrenia atypical antipsychotic

N NH N N N N N N N Cl Cl O O Loxapine Amoxapine Mirtazapine typical antipsychotic antidepreassant Tetracyclic antidepreassant

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5.6 AIM OF CURRENT WORK

Thienodiazepines have been the object of intense studies since the early 1960s because of their value in psychotherapy. An impressive number of synthetic routes have thus been described. Recently the attention has been concentrated on the synthesis of analogs having heterocycles in place of the benzene ring and on compounds having additional fused heterocyclic rings. Our target was the synthesis of new compounds possessing 7-membered rings with two heteroatom a 1,4-diazepines having fused heterocyclic ring of coumarin and thiophene and cyclic secondary amine as a side chain. Substituted 8-amino-10-methyl chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one hydrochlorides treated with cyclic secondary amine (N-methyl, N-ethyl, N-phenyl and N-benzylpiperazine, piperidine, morpholine, pyrrrolidine, 2-methylpiperidine and piperazine) in DMSO and toluene at reflux condition to give title compounds. The products were characterized by FT-IR, mass spectra, 1H NMR and elemental analysis. The newly synthesized compounds were subjected to various biological activities viz., antimicrobial, antimycobacterial, anticancer and antiviral.

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5.7 REACTION SCHEMES

5.7.1 Preparation of 4-chloro-3-nitrocoumarins

5.7.2 Preparation of 2-amino-5-methylthiophene-3-carbonitrile

5.7.3 Preparation of 5-methyl-2-((3-nitro-coumarin-4-yl)amino)thiophene-3- carbonitriles

5.7.4 Preparation of 8-amino-10-methylcoumarino[3,4-b]thieno[2,3-e] [1,4]diazepine hydrochlorides

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5.7.5 Preparation of 10-methyl-8-((substituted)amino)chromeno[3,4-b]thieno [2,3-e][1,4]diazepin-6(12H)-ones

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5.8 EXPERIMENTAL

5.8.1 MATERIALS AND METHODS Melting points were determined in open capillary tubes and are uncorrected. Formation of the compounds was routinely checked by TLC on silica gel-G plates of 0.5 mm thickness and spots were located by iodine. IR spectra were recorded Shimadzu FT-IR-8400 instrument using KBr method. Mass spectra were recorded on Shimadzu GC-MS-QP-2010 model using Direct Injection Probe technique. 1H NMR

was determined in DMSO-d6 solution on a Bruker Ac 400 MHz spectrometer. Elemental analysis of the all the synthesized compounds was carried out on Elemental Vario EL III Carlo Erba 1108 model and the results are in agreements with the structures assigned.

5.8.2 Preparation of 4-chloro-3-nitrocoumarins

According to the previously published procedure57, 4-hydroxycoumarin was

nitrated in glacial AcOH with 72% HNO3 to afford 4-hydroxy-3-nitrocoumarin. Starting compound 4-choro-3-nitrocoumarin was prepared from 4-hydroxy-3- nitrocoumarin following the method of Kaljaj et al. 58 The preparation was carried out in the following manner: N,N-dimethylformamide (DMF, 0.1 mol) was cooled to 10

ºC in an ice bath. With stirring, POCl3 (0.1 mol) was added dropwise, and the obtained mixture was stirred for an additional 15 min. Then, the ice bath was removed and the reaction was left to proceed at room temperature for a further 15 min. Finally, the solution of 4-hydroxy-3-nitrocoumarin (0.1 mol) in DMF (50 mL) was added dropwise. After 15 minutes of stirring, the reaction was stopped by adding cold water (60 mL). The precipitated solid was collected by filtration and washed with saturated sodium-bicarbonate solution and water.

5.8.3 Preparation of 2-amino-5-methylthiophene-3-carbonitrile

A mixture of sulfur (0.1 mol), propionaldehyde (0.12 mol) and DMF (20 mL) was placed in a 100 mL flask and cooled in an ice bath. Triethylamine (0.06 mol) was added drop wise over 30 minutes to the stirred reaction mixture and the temperature was maintained between 5-10 °C. The pot was warmed to 15-20 °C, and stirred at 15-

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20 °C over 50 minutes. A solution of malononitrile (0.1 mol) in DMF (15 mL) was added drop wise at a temperature of 15-20 °C. After the addition was complete, the mixture was stirred at 15-20 °C for 45 minutes. After checking TLC for malanonitrile the mixture was poured onto ice/water (180 mL) while stirring. A solid precipitate was collected by filtration, washed thoroughly with water, and dried overnight, to give 2-amino-5-methylthiophene-3-carbonitrile.

5.8.4 Preparation of 5-methyl-2-((substituted-3-nitrocoumarin-4-yl)amino)thio -phene-3-carbonitriles

A mixture of 4-chloro-3-nitrocoumarin (0.01 mol), 2-Amino-5-methylthiophene-3-carbonitrile (0.01 mol) and methanol (15 mL) place in 100 mL flat bottom flask with magnetic needle. Triethylamine (0.011 mol) was added drop wise with stirring at room temperature and the resultant mixture was heated under reflux condition for 3-4 hours. After the completion of the reaction as monitored by TLC for both starting material, the reaction mixture was allow to cooled at room temperature and the formed solid was then filtered by vacuum filtration, washed with cold methanol and dried to give title product which was then used for next step without any purification.

5.8.5 Preparation of 8-amino-10-methyl(substituted)coumarino[3,4-b]thieno [2,3-e][1,4]diazepine hydrochlorides

To a 100 mL round bottom flask placed 5-methyl-2-((3-nitro-2-oxo-2H- chromen-4-yl) amino) thiophene-3-carbonitriles (0.01 mol) and 95 % ethanol (20 mL) and a solution of stannous chloride dihydrate (0.03) in conc. hydrochloric acid (20 mL) was added slowly with stirring at room temperature and the resultant mixture was reflux for 4-5 hours. After completion of reaction as monitored by TLC, the reaction mixture was allowed to cool to 20-25 °C. The formed solid was collected by filtration, washed with ethanol (10 mL) and then with water (10 mL), dried and crystallized from ethanol to afford the desired product.

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5.8.6 Preparation of 10-methyl-8-((substituted)amino)chromeno[3,4-b]thieno [2,3-e][1,4]diazepin-6(12H)-ones

To a 50 mL round bottom flask placed 8-amino-10-methylchromeno[3,4- b]thieno[2,3-e][1,4]diazepin-6(12H)-one hydrochlorides (0.01 mol) and it was reflux in a mixture of appropriate secondary amine (9 mL), DMSO (15 mL) and toluene (15 mL) for 6 to 8 hours. After completion of reaction as monitored by TLC, the reaction mixture was allowed to cool and the solvent evaporated under reduce pressure at 80 °C. The residue was poured on to ice-water to formed solid, it was collected by filtration, washed with water (10 mL), dried and crystallized from chloroform to afford the desired products.

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5.9 PHYSICAL DATA

Physical Data of 10-methyl-8-((substituted)amino)chromeno[3,4-b]thieno [2,3- e][1,4]diazepin-6(12H)-ones

M. P. Yield % Code R NR1R2 Rf °C

BAJ-301 7-CH3 N 212-214 54 0.42

BAJ-302 7, 8-CH3 N 244-246 57 0.41

BAJ-303 8-CH3 N 110-112 52 0.44

N BAJ-304 7, 8-CH3 138-140 58 0.45

BAJ-305 8-CH3 N 130-132 50 0.47

N BAJ-306 7, 8-CH3 254-256 56 0.46 Ph BAJ-307 8-CH3 N 244-246 60 0.43

BAJ-308 7, 8-CH3 N 260-262 66 0.48 Ph BAJ-309 8-CH3 252-254 53 0.51 N BAJ-310 7, 8-CH3 140-142 55 0.53

BAJ-311 8-CH3 218-220 48 0.54 N

BAJ-312 7, 8-CH3 O 202-204 53 0.57

BAJ-313 8-CH3 216-218 57 0.50 N BAJ-314 7, 8-CH3 180-182 52 0.52

BAJ-315 8-CH3 N 222-224 47 0.44

BAJ-316 7, 8-CH3 N 50 0.41 H 110-112

BAJ-317 8-CH3 140-142 42 0.46 N BAJ-318 7, 8-CH3 148-150 41 0.48

Rf value was determined using solvent system = Chloroform: Methanol (8:2)

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5.10 SPECTRAL DISCUSSION

5.10.1 IR SPECTRA

IR spectra of the synthesized compounds were recorded on Shimadzu FT-IR 8400 model using KBr method. Various functional groups present were identified by characteristic frequency obtained for them. For chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one derivatives, a characteristic band of secondary amine group was observed in the range of 3348-3213 cm-1. Confirmatory band for carbonyl group of coumarin ring was observed at 1707- 1676 cm-1. The coumarin moiety showed the ring skeleton vibrations at 1624-1604, 1599-1569, 1568-1520 and 1471-1440 cm-1. The ether (C-O-C) was observed at 1087-1058 cm-1.

5.10.2 MASS SPECTRA

5.10.3 1H NMR SPECTRA

1H NMR spectra of the synthesized compounds were recorded on Bruker

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5.10.4 13C NMR SPECTRA

13C NMR spectra of the synthesized compounds were recorded on Bruker

Avance II 300 spectrometer by making a solution of samples in DMSO-d6 solvent using tetramethylsilane (TMS) as the internal standard unless otherwise mentioned. Methyl carbon observed between 11.66-20.92 δ ppm, all type of methylene carbons were observed at 24.25-66.05 δ ppm and aromatic carbon observed between 113.99- 148.23 δ ppm while cyclic keto carbon was observed at 148.01-150.18 δ ppm. The aromatic carbon attached with secondary amino (C-NH-C) group was observed at 149.44-158.71 δ ppm and aromatic carbon attached with tertiary nitrogen atom was observed at 160.41-160.98 δ ppm. The methylene groups were also identified by DEPT 135 spectrum.

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5.11 ANALYTICAL DATA

4,10-dimethyl-8-(4-methylpiperazin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-301) Yield: 54%; IR (cm-1): 3235 (-N-H stretching of secondary amine), 3034 (-C-H

stretching of aromatic ring), 2954 (-C-H asymmetrical stretching of CH3 group), 2849

(-C-H symmetrical stretching of CH3 group), 1681 (-C=O stretching of coumarin ring), 1624, 1573, 1539, 1500 (-C=C stretching of aromatic ring), 1368 (-C-H

asymmetrical deformation of -CH3 group), 1312 (-C-H symmetrical deformation of

CH3 group), 1252 (-C-N vibration of amine), 1069 (-C-O-C stretching of coumarin

ring); MS: m/z 394; Anal. Calcd. for C21H22N4O2S: C, 63.94; H, 5.62; N, 14.20.

3,4,10-trimethyl-8-(4-methylpiperazin-1-yl)chromeno[3,4-b]thieno[2,3-e] [1,4]diazepin-6(12H)-one (BAJ-302) Yield: 57%; IR (cm-1): 3279 (-N-H stretching of secondary amine), 3003 (-C-H

stretching of aromatic ring), 2918 (-C-H asymmetrical stretching of CH3 group), 2854

(-C-H symmetrical stretching of CH3 group), 1680 (-C=O stretching of coumarin ring), 1604, 1587, 1556 and 1440 (-C=C- stretching of aromatic ring), 1373 (--C-H

asymmetrical deformation of -CH3 group), 1342 (-C-H symmetrical deformation of

CH3 group), 1255 (-C-N vibration of amine), 1066 (-C-O-C stretching of coumarin 1 ring); H NMR (DMSO-d6) δ ppm: 2.28 (s, 6H), 2.32 (s, 3H), 2.33 (s, 3H), 2.38 (s, 4H), 3.47 (s, 4H), 6.34 (s, 1H), 7.06-7.08 (d, 1H, J = 8.2 Hz), 7.68-7.70 (d, 1H, J = 8.28 Hz), 7.87 (s, 1H); 13C NMR δ ppm: 11.27, 15.08, 19.70, 45.66, 46.14, 54.41, 114.17, 118.65, 120.52, 120.61, 121.86, 123.14, 124.95, 130.52, 138.45, 144.73,

148.22, 149.98, 158.41, 160.37; MS: m/z 408; Anal. Calcd. for C22H24N4O2S: C, 64.68; H, 5.92; N, 13.71.

8-(4-ethylpiperazin-1-yl)-4,10-dimethylchromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-303) Yield: 52%; IR (cm-1): 3252 (-N-H stretching of secondary amine), 3031 (-C-H

stretching of aromatic ring), 2965 (-C-H asymmetrical stretching of CH3 group), 2852

(-C-H symmetrical stretching of CH3 group), 1689 (-C=O stretching of coumarin ring), 1608, 1578, 1550 and 1441 (-C=C- stretching of aromatic ring), 1382 (-C-H

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asymmetrical deformation of -CH3 group), 1340(-C-H symmetrical deformation of

CH3 group), 1249 (-C-N vibration of amine), 1075 (-C-O-C stretching of coumarin

ring); MS: m/z 408; Anal. Calcd. for C22H24N4O2S: C, 64.68; H, 5.92; N, 13.71.

8-(4-ethylpiperazin-1-yl)-3,4,10-trimethylchromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-304) Yield: 58%; IR (cm-1): 3269 (-N-H stretching of secondary amine), 3029 (-C-H

stretching of aromatic ring), 2957 (-C-H asymmetrical stretching of CH3 group), 2856

(-C-H symmetrical stretching of CH3 group), 1691 (-C=O stretching of coumarin ring), 1605, 1582, 1545, 1464 (-C=C- stretching of aromatic ring), 1386 (-C-H

asymmetrical deformation of -CH3 group), 1340 (-C-H symmetrical deformation of

CH3 group), 1254 (-C-N vibration of amine), 1073 (-C-O-C stretching of coumarin

ring); MS: m/z 422; Anal. Calcd. for C23H26N4O2S: C, 65.38; H,6.20; N, 13.26.

8-(4-benzylpiperazin-1-yl)-4,10-dimethylchromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-305) Yield: 50%; IR (cm-1): 3274 (-N-H stretching of secondary amine), 3072 and 3005 (-

C-H stretching of aromatic ring), 2964 (-C-H asymmetrical stretching of CH3 group),

2878 (-C-H symmetrical stretching of CH3 group), 1689 (-C=O stretching of coumarin ring), 1624, 1569, 1555, 1462 (-C=C- stretching of aromatic ring), 1376 (-

C-H asymmetrical deformation of -CH3 group), 1314 (-C-H symmetrical deformation

of CH3 group), 1250 (-C-N vibration of amine), 1070 (-C-O-C stretching of coumarin

ring); MS: m/z 470; Anal. Calcd. for C27H26N4O2S: C, 68.91; H, 5.57; N, 11.91.

8-(4-benzylpiperazin-1-yl)-3,4,10-trimethylchromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-306) Yield: 56%; IR (cm-1): 3285 (-N-H stretching of secondary amine), 3066 (-C-H

stretching of aromatic ring), 2975 (-C-H asymmetrical stretching of CH3 group), 2849

(-C-H symmetrical stretching of CH3 group), 1704 (-C=O stretching of coumarin ring), 1621, 1570, 1528, 1441 (-C=C- stretching of aromatic ring), 1382 (-C-H

asymmetrical deformation of -CH3 group), 1339 (-C-H symmetrical deformation of

CH3 group), 1241 (-C-N vibration of amine), 1069 (-C-O-C stretching of coumarin

ring); MS: m/z 484; Anal. Calcd. for C28H28N4O2S: C, 69.40; H, 5.82; N, 11.56.

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8-(4-phenylpiperazin-1-yl)-4,10-dimethylchromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-307) Yield: 60%; IR (cm-1): 3319 (-N-H stretching of secondary amine), 3061 (-C-H

stretching of aromatic ring), 2918 (-C-H asymmetrical stretching of CH3 group), 2850

(-C-H symmetrical stretching of CH3 group), 1676 (-C=O stretching of coumarin ring), 1629, 1599, 1568 and 1521 (-C=C- stretching of aromatic ring), 1375 (C-H

asymmetrical deformation of -CH3 group), 1348 (-C-H symmetrical deformation of

CH3 group), 1259 (-C-N vibration of amine), 1076 (-C-O-C stretching of coumarin 1 ring); H NMR (DMSO-d6) δ ppm: 2.34 (s, 3H), 2.38 (s, 3H), 3.24 (s, 4H), 3.66 (s, 4H), 6.41 (s, 1H), 6.80-6.83 (t, 1H), 6.94-6.96 (d, 2H, J = 8.24 Hz), 7.14-7.18 (t, 1H), 7.21-7.25 (t, 2H), 7.27-7.29 (d, 1H, J = 7.32 Hz), 7.81-7.83 (d, 1H, J = 7.92 Hz); 13C NMR δ ppm: 15.10, 15.36, 46.23, 48.54, 115.77, 116.26, 119.35 119.63, 120.43, 121.37, 121.83, 123.14, 124.84, 128.72, 130.59, 130.72, 144.63, 148.41, 150.37,

150.75, 158.62, 160.17; MS: m/z 456; Anal. Calcd. for C26H24N4O2S: C, 68.40; H, 5.30; N, 12.27.

8-(4-phenylpiperazin-1-yl)-3,4,10-trimethylchromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-308) Yield: 66%; IR (cm-1): 3289 (-N-H stretching of secondary amine), 3008 (-C-H

stretching of aromatic ring), 2972 (-C-H asymmetrical stretching of CH3 group), 2843

(-C-H symmetrical stretching of CH3 group), 1694 (-C=O stretching of coumarin ring), 1625, 1576, 1526, 1461 (-C=C- stretching of aromatic ring), 1378 (-C-H

asymmetrical deformation of -CH3 group), 1351 (-C-H symmetrical deformation of

CH3 group), 1244 (-C-N vibration of amine), 1069 (-C-O-C stretching of coumarin

ring); MS: m/z 470; Anal. Calcd. for C27H26N4O2S: C, 68.91; H, 5.57; N, 11.91.

4,10-dimethyl-8-(piperidin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin- 6(12H) -one (BAJ-309) Yield: 53%; IR (cm-1): 3295 (-N-H stretching of secondary amine), 3075 (-C-H

stretching of aromatic ring), 2985 (-C-H asymmetrical stretching of CH3 group), 2849

(-C-H symmetrical stretching of CH3 group), 1699 (-C=O stretching of coumarin ring), 1621, 1575, 1541, 1462 (-C=C- stretching of aromatic ring), 1361 (-C-H

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asymmetrical deformation of -CH3 group), 1332 (-C-H symmetrical deformation of

CH3 group), 1245 (-C-N vibration of amine), 1068 (-C-O-C stretching of coumarin

ring); MS: m/z 379; Anal. Calcd. for C21H21N3O2S: C, 66.47; H, 5.58; N, 11.07.

3,4,10-trimethyl-8-(piperidin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6- (12H)-one (BAJ-310) Yield: 55%; IR (cm-1): 3324 (-N-H stretching of secondary amine), 3026 (-C-H

stretching of aromatic ring), 2965 (-C-H asymmetrical stretching of CH3 group), 2872

(-C-H symmetrical stretching of CH3 group), 1703 (-C=O stretching of coumarin ring), 1621, 1579, 1560, 1454 (-C=C- stretching of aromatic ring), 1369 (-C-H

asymmetrical deformation of -CH3 group), 1338 (-C-H symmetrical deformation of

CH3 group), 1252 (-C-N vibration of amine), 1074 (-C-O-C stretching of coumarin

ring); MS: m/z 393; Anal. Calcd. for C22H23N3O2S: C, 67.15; H, 5.89; N, 10.68.

4,10-dimethyl-8-morpholinochromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)- one (BAJ-311) Yield: 48%; IR (cm-1): 3300 (-N-H stretching of secondary amine), 3124 and 3063 (-

C-H stretching of aromatic ring), 2947 (-C-H asymmetrical stretching of CH3 group),

2854 (C-H symmetrical stretching of CH3 group), 1703 (-C=O stretching of coumarin ring), 1610, 1583, 1564 and 1519 (-C=C- stretching of aromatic ring), 1431 (-C-H

asymmetrical deformation of -CH3 group), 1346 (-C-H symmetrical deformation of

CH3 group), 1271 (-C-N vibration of amine), 1070 (-C-O-C stretching of coumarin 1 ring); H NMR (DMSO-d6) δ ppm: 2.32 (s, 3H), 2.37 (s, 3H), 3.49 (s, 4H), 3.71 (s, 4H), 6.35 (s, 1H), 7.14-7.18 (t, 1H), 7.27-7.29 (d, 1H, J = 7.28 Hz), 7.80-7.82 (d, 1H, J = 7.92 Hz), 7.94 (s, 1H); 13C NMR δ ppm: 15.06, 15.34, 46.93, 66.04, 116.24, 119.63 120.28, 121.41, 121.73, 123.13, 124.82, 130.57, 130.73, 144.55, 148.40,

150.33, 158.76, 160.15; MS: m/z 381; Anal. Calcd. for C20H19N3O3S: C, 62.97; H, 5.02; N, 11.02.

3,4,10-trimethyl-8-morpholinochromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)- one (BAJ-312) Yield: 53%; IR (cm-1): 3254 (-N-H stretching of secondary amine), 3046 (-C-H

stretching of aromatic ring), 2965 (-C-H asymmetrical stretching of CH3 group), 2874

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(-C-H symmetrical stretching of CH3 group), 1706 (-C=O stretching of coumarin ring), 1624, 1568, 1521, 1504 (-C=C- stretching of aromatic ring), 1421 (-C-H

asymmetrical deformation of -CH3 group), 1347 (-C-H symmetrical deformation of

CH3 group), 1248 (-C-N vibration of amine), 1084 (-C-O-C stretching of coumarin

ring); MS: m/z 395; Anal. Calcd. for C21H21N3O3S: C, 63.78; H, 5.35; N, 10.63.

4,10-dimethyl-8-(pyrrolidin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6- (12H)-one (BAJ-313) Yield: 57%; IR (cm-1): 3281 (-N-H stretching of secondary amine), 3072 (-C-H

stretching of aromatic ring), 2959 (-C-H asymmetrical stretching of CH3 group), 2868

(-C-H symmetrical stretching of CH3 group), 1688(-C=O stretching of coumarin ring), 1615, 1561, 1520, 1503 (-C=C- stretching of aromatic ring), 1416 (-C-H

asymmetrical deformation of -CH3 group), 1340 (-C-H symmetrical deformation of

CH3 group), 1251 (-C-N vibration of amine), 1073 (-C-O-C stretching of coumarin

ring); MS: m/z 365; Anal. Calcd. for C20H19N3O2S: C, 65.73; H, 5.24; N, 11.50.

3,4,10-trimethyl-8-(pyrrolidin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6- (12H)-one (BAJ-314) Yield: 52%; IR (cm-1): 3348 (-N-H stretching of secondary amine), 3078 and 3010 (-

C-H stretching of aromatic ring), 2951 (-C-H asymmetrical stretching of CH3 group),

2854 (-C-H symmetrical stretching of CH3 group), 1699 (-C=O stretching of coumarin ring), 1627, 1583, 1546 and 1519 (-C=C stretching of aromatic ring), 1371

(-C-H asymmetrical deformation of -CH3 group), 1294 (-C-H symmetrical

deformation of CH3 group), 1271 (-C-N vibration of amine),1062 (-C-O-C stretching

of coumarin ring); MS: m/z 379; Anal. Calcd. for C21H21N3O2S: C, 66.47; H, 5.58; N, 11.07.

4,10-dimethyl-8-(piperazin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6- (12H)-one (BAJ-315) Yield: 47%; IR (cm-1): 3250 (-N-H stretching of secondary amine), 3060 (-C-H

stretching of aromatic ring), 2974 (-C-H asymmetrical stretching of CH3 group), 2845

(-C-H symmetrical stretching of CH3 group), 1705 (-C=O stretching of coumarin ring), 1621, 1569, 1524, 1499 (-C=C- stretching of aromatic ring), 1417 (-C-H

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asymmetrical deformation of -CH3 group), 1349 (-C-H symmetrical deformation of

CH3 group), 1248 (-C-N vibration of amine), 1072 (-C-O-C stretching of coumarin

ring); MS: m/z 380; Anal. Calcd. for C20H20N4O2S: C, 63.14; H, 5.30; N, 14.73.

3,4,10-trimethyl-8-(piperazin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6- (12H)-one (BAJ-316) Yield: 50%; IR (cm-1): 3271 (-N-H stretching of secondary amine), 3062 (-C-H

stretching of aromatic ring), 2951 (-C-H asymmetrical stretching of CH3 group), 2860

(-C-H symmetrical stretching of CH3 group), 1698 (-C=O stretching of coumarin ring), 1619, 1568, 1532, 1500 (-C=C- stretching of aromatic ring), 1417 (-C-H

asymmetrical deformation of -CH3 group), 1345 (-C-H symmetrical deformation of

CH3 group), 1247 (-C-N vibration of amine), 1079 (-C-O-C stretching of coumarin

ring); MS: m/z 394; Anal. Calcd. for C21H22N4O2S: C, 63.94; H, 5.62; N, 14.20.

4,10-dimethyl-8-(2-methylpiperidin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-317) Yield: 42%; IR (cm-1): 3289 (--N-H stretching of secondary amine), 3009 (-C-H

stretching of aromatic ring), 2961 (-C-H asymmetrical stretching of CH3 group), 2858

(-C-H symmetrical stretching of CH3 group), 1690 (-C=O stretching of coumarin ring), 1615, 1564, 1530, 1504 (-C=C- stretching of aromatic ring), 1414 (-C-H

asymmetrical deformation of -CH3 group), 1347 (-C-H symmetrical deformation of

CH3 group), 1241 (-C-N vibration of amine), 1072 (-C-O-C stretching of coumarin

ring); MS: m/z 393; Anal. Calcd. for C22H23N3O2S: C, 67.15; H, 5.89; N, 10.68.

3,4,10-trimethyl-8-(2-methylpiperidin-1-yl)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one (BAJ-318) Yield: 41%; IR (cm-1): 3277 (-N-H stretching of secondary amine), 3071 (-C-H

stretching of aromatic ring), 2965 (-C-H asymmetrical stretching of CH3 group), 2845

(-C-H symmetrical stretching of CH3 group), 1693 (-C=O stretching of coumarin ring), 1621, 1571, 1538, 1502 (-C=C- stretching of aromatic ring), 1421 (-C-H

asymmetrical deformation of -CH3 group), 1356 (-C-H symmetrical deformation of

CH3 group), 1240 (-C-N vibration of amine), 1081 (-C-O-C stretching of coumarin

ring); MS: m/z 407; Anal. Calcd. for C23H25N3O2S: C, 67.79; H, 6.18; N, 10.31.

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5.12 RESULTS AND DISCUSSION

This chapter deals with synthesis of substituted 10-methyl-8-((substituted)amino)chromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-ones from 8-amino- 10-methylchromeno[3,4-b]thieno[2,3-e][1,4]diazepin-6(12H)-one hydrochloride. The synthesis was done by using two different 8-amino-10-methylchromeno[3,4- b]thieno[2,3-e][1,4]diazepin-6(12H)-one hydrochloride and nine different cyclic secondary amine. Total 18 compounds were synthesized and characterized using spectroscopic technique.

5.13 CONCLUSION

In conclusion, the synthesis of title compounds has been done by using 3.0 mole equivalent secondary amine and DMSO/toluene as solvents mixture at 100 °C. Most of the piperazinyl derivatives were easily synthesized and purified in chloroform to get crystalline products. Synthesized compounds were explored for performing various biological activities.

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5.14 REPREENTATIVE SPECTRA 5.14.1 IR spectrum of BAJ-302

5.14.2 Mass spectrum of BAJ-302

O O

N HN N N S

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5.14.3 1H NMR spectrum of BAJ-302

5.14.4 Expanded 1H NMR spectrum of BAJ-302

Department of Chemistry, Saurashtra University, Rajkot-360005 179 Chapter – 5 Synthesis of diazepine derivatives

5.14.5 13C NMR spectrum of BAJ-302

O O

N HN N N S

5.14.6 DEPT 135 spectrum of BAJ-302

Department of Chemistry, Saurashtra University, Rajkot-360005 180 Chapter – 5 Synthesis of diazepine derivatives

5.14.7 IR spectrum of BAJ-307

5.14.8 Mass spectrum of BAJ-307

O O

N HN N N S

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5.14.9 1H NMR spectrum of BAJ-307

5.14.10 Expanded 1H NMR spectrum of BAJ-307

Department of Chemistry, Saurashtra University, Rajkot-360005 182 Chapter – 5 Synthesis of diazepine derivatives

5.14.11 13C NMR spectrum of BAJ-307

5.14.12 DEPT 135 spectrum of BAJ-307

Department of Chemistry, Saurashtra University, Rajkot-360005 183 Chapter – 5 Synthesis of diazepine derivatives

5.14.13 IR spectrum of BAJ-311

5.14.14 Mass specrum of BAJ-311

O O

N HN N O S

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5.14.15 1H NMR specrum of BAJ-311

O O

N HN N O S

5.14.16 Expanded 1H NMR spectrum of BAJ-311

Department of Chemistry, Saurashtra University, Rajkot-360005 185 Chapter – 5 Synthesis of diazepine derivatives

5.14.17 13C NMR spectrum of BAJ-311

O O

N HN N O S

5.14.18 DEPT 135 spectrum of BAJ-311

Department of Chemistry, Saurashtra University, Rajkot-360005 186 Chapter – 5 Synthesis of diazepine derivatives

5.15 REFERENCES

1. Rohtash K., Lown, J. W.; Mini-Reviews in Medicinal Chemistry, 2003, 3, 323. 2. Bertelli, L., Biagi, G., Giorgi, I., Livi, O., Manera, C., Scartoni, V., Martini, C., Giannaccini, G., Trincavelli, L., Barilli, P.L.; Il Farmaco, 1998, 53, 305. 3. Balakrishna, M. S., Kaboudin, B.; Tetrahedron Lett., 2001, 42, 1127. 4. Lattmann, E., Sattayasai, J., Billington, D. C., Poyner, D. R., Puapairoj, P., Tiamkao, S., Airarat, W., Singh, H., Offel, M.; J. Pharmacy and Pharmacology, 2002, 54, 827. 5. Bertelli, L., Biagi, G., Giorgi, I., Livi, O., Manera, C., Scartoni, V., Martini, C., Giannaccini, G., Trincavelli, L., Barili, P. L.; Farmaco, 2000, 53, 305. 6. Katrizky, A. R., Abonia, R., Yang, B., Qi, M., Insuasty, B.; Synthesis, 1998, 1487. 7. Clifford, D. P., Jackson, D., Edwards, R. V., Jefferey, P.; Pestic. Sci., 1976, 7, 453. 8. Werner, W., Wohlrabe, K., Gutsche, W., Jungstand, W., Roemer, W.; Folida Haematol, 1981, 108, 637. 9. Goff, D. A., Zuckermann, R. N.; Org. Chem., 1995, 60, 5744. 10. Lin, W., Li, H., Ming, X., Seela, F.; Org. Biomol. Chem., 2005, 3, 1714. 11. Roger, R., Neilson, D. G.; in The Chemistry of Imidates ed. S. Patay, Wiley, New York, 1960, pp. 179. 12. McCluskey, A., Keller, P. A., Morgan, J., Garner J.; Org. Biomol. Chem., 2003, 1, 3353. 13. Kuhnert, N., Clemens, I., Walsh, R.; Org. Biomol. Chem., 2005, 3, 1694. 14. Fryer, R. I., Earley, J. V., Field, G. F., Zally, W., Sternbach, L. H.; J. Org. Chem., 1969, 34, 1143. 15. Schutz, H.; Benzodiazepines; Springer: Heidelberg, Germany, 1982. 16. Randall, L. O., Kamel, B., In Benzodiazepines; Garattini, S., Mussini, E., Randall, L. O., Eds.; Raven Press: New York, 1973; p. 27. 17. US3978227. 18. Merluzzi, V., Hargrave, K. D., Labadia, M., Grozinger, K., Skoog, M., Wu, J.C., Shih, C.-K., Eckner, K., Hattox, S., Adams, J., Rosenthal, A. S., Faanes, R., Eckner, R. J., Koup, R. A.,; Sullivan, J. L. Science, 1990, 250, 1411.

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19. Di Braccio, M., Grossi, G., Romoa, G., Vargiu, L., Mura, M., Marongiu, M. E.; Eur. J. Med. Chem., 2001, 36, 935. 20. El-Sayed, A. M., Khodairy, A., Salah, H., Abdel-Ghany, H.; Phosphorus Sulfur Silicon Relat. Elem., 2007, 182, 711. 21. Nagaraja, G. K., Vaidya, V. P., Rai, K. S., Mahadevan, K. M.; Phosphorus, Sulfur Silicon Relat. Elem., 2006, 181, 2797. 22. Nabih, K., Baouid, A., Hasnaoui, A., Kenz, A.; Synth. Commun., 2004, 34, 3565. 23. Reddy, K. V. V., Rao, P. S., Ashok, D.; Synth. Commun., 2000, 30, 1825. 24. US1537757. 25. Tinney, F. J., Sanchez, J. P., Nogas, J. A.; J. Med. Chem., 1974, 17, 624. 26. Sayed, A. A., Sami, S. M., Elfayoumi, A., Mohamed, E. A.; Egyp. J. Chem., 1978, 19, 811. 27. Ghosh, C. K., Khan, S.; Synthesis, 1980, 9, 701. 28. Ghosh, C., Tewari, N.; J. Org. Chem., 1980, 45, 1964. 29. Azuma, Y., Sato, A., Morone, M.; Heterocycles, 1993, 35, 599. 30. Hammal, L., Bouzroura, S.; Synth. Commun., 2007, 37, 501. 31. Savel'ev, V. L., Makarov, A. V., Zagorevskii, V. A.; Khim. Geterotsik. Soedin., 1983, 6, 845. 32. Savel'ev, V. L., Artamonova, O. S., Makarov, A. V., Troitskaya, V. S., Antonova, A. V., Vinokurov, V. G.; Khim. Geterotsikl. Soedin., 1989, 9, 1208. 33. Steinfuehrer, T.; Liebigs Annalen der Chemie, 1992, 1, 23. 34. Sabetie, A., Végh, D., Loupy, A., Floch, L.; Arkivoc, 2001, 6, 122. 35. El-Telbani, E. M., Keshk, E. M., Roaiah, H. F.; Egyp. J. Chem., 2007, 50, 569. 36. Fryer, R. I., Earley, J. V., Field, G. F., Zally, W., Sternbach, L. H.; J.Org.Chem., 1969, 34, 1143. 37. Schmutz, J.; Arzneim.-Forsch., 1975, 25, 712. 38. Jilek, J. O., Sindelar, K., Rajsner, M., Dlabac, A., Metysova, J., Votava, Z., Pomykvacek, J.; Protiva, M.; Coll. Caech. Chem. Commun., 1975, 40, 2887. 39. Eichenberger, E.; Arzneim. -Forsch., 1984, 34, 110. 40. Press, J. B., Hofmann, C. M., Safir, S. R.; J. Het. Chem., 1980, 17, 1361. 41. Press, J. B., Hofmann, C. M., Eudy, N. H., Day, I. P., Greenblatt, E.N., Safir, S. R.; J. Med. Chem., 1981, 24, 154.

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Chapter – 5 Synthesis of diazepine derivatives

42. Press, J. B., Hofmann, C. M., Eudy, N. H., Fanshawe, W. J., Day, I. P., Greenblatt, E. N., Safir, S. R.; J. Med. Chem., 1979, 22, 725. 43. Glamkowski, E. J., Chiang, Y.; J. Het. Chem., 1987, 24, 733. 44. Glamkowski, E. J., Chiang, Y.; J. Het. Chem., 1987, 24, 1599. 45. US6271225. 46. Seio, K., Arita, M., Fujimoto, T., Yamamoto, I.; J. Het. Chem., 2002, 39, 163. 47. Leyva-Pérez, A., Cabrero-Antonino, J. R., Corma, A.; Tetrahedron, 2010, 66, 8203. 48. Heitmann, W., Liepmann, H., Matzel, U., Zeugner, H., Fuchs, A. M., Krahling, H., Ruhland, M., Mol, F., Tulp, M. Th.; M. Eur. J. Med. Chem., 1988, 23, 249. 49. Kusanur1, R. A., Ghate, M., Kulkarni, M. V.; J. Chem. Sci., 2004, 116, 265. 50. Namanishi, M., Tahara, T., Araki, K., Shiroki, M.; US patent, 3920679, 1975. 51. Angst, J., Bente, D., Berner, P., Heimann, H., Helmchen, H., Hippus, H.; Pharmakopsychiatr./Neuro-Psychopharmakol., 1 971, 4, 201. 52. Fischer-Cornelssen, K. A.; Arzrzeim.-Forsch., 1984, 34, 125. 53. Chakrabarti, J. K., Hotten, T. M., Pullar, I. A., Tye, N. C.; J. Med. Chem., 1989, 32, 2573. 54. Chakrabarti, J. K., Hotten, T. M., Pullar, I. A., Steggles, D. J.; J. Med. Chem., 1989, 32, 2375. 55. Hussenether, T., Hubner, H., Gmeiner, P., Troschutz, R.; Bioorg. Med. Chem., 2004, 12, 2625. 56. Sasikumar, T. K., Burnett, D. A., Zhang, H., Smith-Torhan, A., Fawzi, A., Lachowicz, J. E.; Bioorg. Med. Chem. Lett., 2006, 16, 4543. 57. Savel’ev, V. L., Artamonova, O. S., Troitskaya, V. S., Vinokurov, V. G., Zagorevskii, V. A.; Khim. Geterotsikl., 1973, 7, 816. 58. Kaljaj, V., Trkovnik, M., Stefanović-Kaljaj, L.; J. Serb. Chem. Soc., 1987, 52, 183.

Department of Chemistry, Saurashtra University, Rajkot-360005 189

Biological evaluation of synthesized compounds

Biological Evaluation of Synthesized Compounds …

INTRODUCTION

The present chapter deals with the preliminary biological screening results of some synthesized compounds during the course of invention. In the current chapter, biological aspects of anti tubercular screening were described along with the activity protocols and activity data obtained by preliminary screening In vitro. Finally on the screening results conclusion is also narrated.

The ant tubercular screening of all the synthesized compounds was carried out at Tuberculosis Antimicrobial Acquisition and Coordinating Facility (TAACF), Alabama, USA.

PROCEDURE FOR THE RESAZURIN MIC ASSAY

The resazurin MIC assay, developed by Collins and Franzblau (1997), is a colorimetric assay used to test compounds for antimycobacterial activity. A color change from blue to pink is observed when growth occurs. Compounds are initially tested at a single point concentration of 10 μg/ml against Mycobacteruim tuberculosis H37Rv (H37Rv), obtained from Colorado State University, Fort Collins, CO. If compounds are active at the 10 μg/ml level, they are further tested in an MIC assay at 8 concentrations in a dose range between 10 to 0.078 μg/ml.

¾ Receipt and Preparation of Test Compounds

Upon receipt, test compounds are logged into the inventory spreadsheet and placed in a -20ºC freezer. The day of the experiment, one vial from each compound is reconstituted using the supplier’s recommended solvent to achieve a stock concentration of 3.2 mg/ml.

¾ Inoculum Preparation

H37Rv is grown in Middlebrook 7H9 broth medium (7H9 medium) supplemented with 0.2% (v/v) glycerol, 10% (v/v) ADC (albumin, dextrose, catalase), and 0.05% (v/v) Tween 80. The bacteria are inoculated in 50 ml of 7H9 medium in 1 liter roller bottles that are placed on a roller bottle apparatus in an ambient 37oC incubator.

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

When the cells reach an OD600 of 0.150 (equivalent to ~1.5 x 107 CFU/ml), they are diluted 200-fold in 7H9 medium.

¾ Single Point Concentration Procedure

The procedure is the same as that used for the MIC procedure described below, but only the first 2 fold dilution is made that reduces the stock solution to 1.6 mg/ml. An additional 1:10 dilution is made in water (see Step 3 below) which reduces the stock solution further to 0.16 mg/ml. Addition of 6.25 μl of the 1:10 dilution to the wells in a final volume of 100 μl will give rise to a concentration equivalent to 10 μg/ml (see Step 2 below).

¾ MIC Procedure

1. 20 μl of the 3.2 mg/ml test compound is added to a 96-well microtiter plate. 2. 2-fold dilutions are made by the addition of 20 μl of diluent.

Expected final Test Compound = 3.2 mg/ml dose level (μg/ml) Dilute 1:2

10 1st dilution of 8 = 1.6 mg/ml Dilute 1:2 5 2nd dilution of 8 = 0.8 mg/ml Dilute 1:2 2.5 3rd dilution of 8 = 0.4 mg/ml Dilute 1:2 1.25 4th dilution of 8 = 0.2 mg/ml Dilute 1:2 0.625 5th dilution of 8 = 0.1 mg/ml Dilute 1:2 0.312 6th dilution of 8 = 0.05 mg/ml Dilute 1:2 0.156 7th dilution of 8 = 0.025 mg/ml Dilute 1:2 0.078 8th dilution of 8 = 0.0125 mg/ml 3. Each dilution is further diluted 1:10 in sterile water (10 μl of dilution to 90 μl of sterile water). Note: The additional 10-fold dilution in water is required when DMSO is used as solvent to minimize toxicity to the bacteria. For uniformity in the assay procedure, this dilution step is used even if water or other solvents are used. 4. 6.25 μl of each dilution is transferred to duplicate 96-well test plates.

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

5. 93.75 μl of the cell suspension (~ 104 bacteria) in 7H9 medium is added to the test plates. 6. Positive, negative, sterility and resazurin controls are tested. a. Positive controls include: rifampicin and isoniazid b. Negative controls include: i. cell culture with solvent and water ii. cell culture only c. Sterility controls include: i. media only ii. media with solvent and water d. Resazurin control includes one plate containing the diluted compounds with resazurin only. No bacterial suspension is added. This control plate is needed to verify whether the compound reacts with resazurin that could possibly elicit fluorescence. 7. The 96 well test plates are incubated in an ambient 37ºC incubator for 6 days. 8. After the 6 day incubation, 5 μl of a 0.05% sterile resazurin solution is added to each well of the 96-well plate. The plates are placed in an ambient 37ºC incubator for 2 days. 9. After the 2 day incubation, a visual evaluation and fluorimetric read-out is performed. The results are expressed as μg/ml (visual evaluation) and as IC50 and IC90 (fluoremetric readout)

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

TABLE-1 – IC50 VALUE OF NEWLY SYNTHESIZED COMPOUNDS

Compound Structure Solvent Results (µg/mL) ID

BAJ-201 DMSO >10

BAJ-202 DMSO >10

BAJ-203 DMSO >10

BAJ-204 DMSO >10

BAJ-205 DMSO >10

BAJ-206 DMSO >10

BAJ-207 DMSO >10

BAJ-208 DMSO >10

BAJ-209 DMSO >10

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

BAJ-210 DMSO >10

BAJ-211 DMSO >10

BAJ-212 DMSO >10

BAJ-213 DMSO >10

BAJ-216 DMSO >10

BAJ-217 DMSO >10

BAJ-218 DMSO >10

BAJ-219 DMSO >10

BAJ-220 DMSO >10

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

BAJ-221 DMSO >10

BAJ-222 DMSO >10

BAJ-225 DMSO >10

BAJ-226 DMSO >10

BAJ-227 DMSO >10

BAJ-228 DMSO >10

BAJ-229 DMSO >10

BAJ-231 DMSO >10

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

BAJ-232 DMSO >10

BAJ-233 DMSO >10

BAJ-234 DMSO >10

BAJ-237 DMSO >10

BAJ-238 DMSO >10

BAJ-239 DMSO >10

O H3C O BAJ-240 Cl DMSO >10 N

O O

BAJ-241 DMSO >10

BAJ-301 DMSO >10

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

BAJ-301 DMSO >10

BAJ-302 DMSO >10

BAJ-303 DMSO >10

BAJ-304 DMSO >10

BAJ-305 DMSO >10

BAJ-306 DMSO >10

BAJ-307 DMSO >10

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

BAJ-308 DMSO >10

BAJ-309 DMSO >10

BAJ-310 DMSO >10

BAJ-311 DMSO >10

BAJ-312 DMSO >10

BAJ-313 DMSO >10

BAJ-315 DMSO >10

Department of Chemistry, Saurashtra University, Rajkot-360005

Biological Evaluation of Synthesized Compounds …

BAJ-316 DMSO >10

BAJ-317 DMSO >10

BAJ-318 DMSO >10

Rifampin DMSO 0.0125

Isoniazid DMSO 0.063

Reference:

Collins, L. A. and S. G. Franzblau. Microplate Alamar Blue Assay versus BACTEC 460 System for High-Throughput Screening of Compounds against Mycobacterium tuberculosis and Mycobacterium avium. Antimicrobial Agents and Chemotherapy, 41:1004-1009 (1997).

Conclusion:

In all 52 novel compounds were screened for Antitubercular Activity. All compounds show MIC value >10 µg/mL and therefore it is necessary to study further other biological activities.

Department of Chemistry, Saurashtra University, Rajkot-360005

Summary of the work done in this thesis

The work represented in the thesis entitled “Studies In Heterocyclic Moieties” is divided into five chapters which can be summarized as under.

Chapter-1 deals with the synthesis of pyrazole derivatives using 5-chloro-2- methoxybenzohydrazide and different α-diketo compounds in presence of Con. HCl as catalysts. Good yield and easy work up is the main significance of this method. The chapter represents 17 compounds including reaction mechanism, IR, 1H NMR, 13C NMR, Mass spectral and other Physical data to support the structure elucidation.

Chapter-2 covers synthesis of functionalized pyrrole derivatives. In this chapter we have developed a novel, rapid and efficient methodology for the synthesis of highly functionalized pyrroles. This process involves one pot four component coupling reaction of 1,3-dicarbonyl compounds, aromatic aldehyde, amines, and nitro alkanes. Considering these advantages and experimental simplicity, this one-pot catalytic transformation clearly represents an appealing methodology for the synthesis of highly functionalized pyrroles. The main advantage of this process is economical, environmental friendly and less time consuming. Total 34 compounds are included in this chapter along with reaction mechanism, IR, 1H NMR, 13C NMR, Mass spectral and other Physical data to support the structure elucidation.

Chapter-3 represents 18 compounds of 3-cyano-4-(alkyl/dialkyl amino)coumarin derivatives. Insertion of the cyano group to the 3rd position is a result of modification in the prior art method of synthesizing isoxazoles. The process delivers high yield and purity and the presence of cyano group is in the interest of biological activity. The chapter covers reaction mechanism, IR, 1H NMR, 13C NMR, DEPT, Mass spectral and other Physical data to support the structure elucidation.

Chapter-4 is an effort to modify well-known Hantzsch synthesis of Dihydropyridines. A successful method was developed by changing the temperature and solvent condition for rapid synthesis of various DHP’s without using the microwave irradiation so as further development of this method may prove to be commercially viable as the class of Dihydropyridine represents many drugs in this

Department of Chemistry, Saurashtra University, Rajkot-360005

Summary of the work done in this thesis

current era. Total 15 synthesized compounds are presented in this chapter. Compounds were characterized by spectral analysis.

Chapter-5 involves the synthesis of chromeno[3,4-b]thieno[2,3-e][1,4]diazepin- 6(12H)-ones and its piperazinyl derivatives. The previously synthesized 5-methyl-2- ((3-nitro-2-oxo-2H-chromen-4-yl)amino)thiophene-3-carbonitriles were reduced and

cyclised by SnCl22H2O/HCl to produce chromenothienodiazepinones, which were treated with various cyclic secondary amine to afforded 18 novel compounds. The chapter covers IR, 1H NMR, 13C NMR, DEPT, Mass spectral and other Physical data to support the structure elucidation.

Biological Activity: The anti tubercular screening done on several newly synthesized molecules. In all compounds were screened. Unfortunately compounds were not shown to the posses moderate activity. In entire thesis, total 102 compounds were prepared during this work. Biological screening of some of the compounds is performed while remaining compounds are under study.

Department of Chemistry, Saurashtra University, Rajkot-360005

Conferences/Seminars/Workshops Attended

CONFERENCES/SEMINARS/WORKSHOPS ATTENDED

¾ ISCB Conference “International conference on Bridging gaps in discovery and development: Chemical & Biological science for affordable health, wellness & sustainbility” at Department of Chemistry, Saurashtra University, Rajkot on 4-7th February-2011

¾ ISCB Conference “International conference on chemical biology for discovery: perspectives and Challenges” at CDRI, Lucknow on 15-18th Jan., 2010.

¾ ISCB Conference “Interplay of Chemical and Biological Sciences: Impact on Health and Environment” at Delhi University, on 26th February - 1st March 2009. ¾ “International Seminar on Recent Developments in Structure and Ligandbased Drug Design” jointly organized by Schrodinger LLC, USA; National Facility for Drug Discovery through New Chemicals Entities Development & Instrumentation support to Small Manufacturing Pharma Enterprises and DSTFIST, UGC-SAP & DST-DPRP Funded Department of Chemistry, Saurashtra University, Rajkot on 23rd, December, 2009.

¾ “National seminar on Alternative Synthetic Strategies for Drugs & Drug Intermediates” at Institute of Pharmacy, Nirma University, Ahmedabad on 13th November, 2009.

¾ “Two Days National Workshop on Patents & Intellectual Property Rights Related Updates” Sponsored by TIFAC & GUJCOST and Organized by DST-FIST, UGC-SAP & DST-DPRP Funded Department of Chemistry, Saurashtra University, Rajkot on 19-20th September, 2009.

¾ DST-FIST, UGC (SAP) supported and GUJCOST Sponsored “National Conference on Selected Topics in Spectroscopy and Stereochemistry” organized by the Department of Chemistry, Saurashtra University, Rajkot on 18-20th March, 2009.

¾ National seminar on “Recent Advances in Chemical Sciences & an Approach to Green Chemistry”, Rajkot on October, 2006.

¾ National workshop on “E-resources in Chemical Synthsis and Natural Products”, Rajkot on March, 2006.

Conferences/Seminars/Workshops Attended

Poster presented at the International Conference:

¾ Synthesis of Nucleoside Reverse Transcriptase Inhibitors: Bis (2 – Propyl) – 7 – [2 – (Phosphonomethoxy) ethyl] – 2 – amino – 6 – chloropurine (7 – isomer) & Bis (2 – Propyl) – 9 – [2 – (Phosphonomethoxy) ethyl] – 2 – amino – 6 – chloropurine (9 – isomer)

Abhay Bavishi, Shrey Parekh, Bhavin Marvania, Ravi Chhaniyara, Anamik Shah*,

Presented at 13th ISCB International conference at Department of Chemistry, Delhi University, Delhi on 26th February‐1st March, 2010.

¾ Synthesis And Antimicrobial Activity of some fused Bicyclic Heterocycles

Abhay Bavishi, and Nikhil Vekariya*

Presented at 14th ISCB International conference at CDRI, Lucknow on 15‐18th Jan., 2010.

¾ Synthesis and biological evaluation of 4‐Styrylcoumarin derivatives as inhibitors of TNF‐α and IL‐6 with anti‐tubercular activity

Abhay Bavishi. Kuldip Upadhyay, Anamik Shah*

Presented at 15th ISCB International conference at Saurashtra University, Rajkot on 4‐7th Feb., 2011.

Publications

PUBLICATION LIST

1. Synnthesis and biological evaluation ofo 4-Styrylcoumarin derivatives as inhibitors of TNF-α and IL-6 with anti-tubercular activity. Kuldip Upadhyay, Abhay Bavishi, Shailesh Thakrar, Ashish Radadiya, Hardev Vala, Shrey

Parekh, Dhairya Bhavsar, Mahesh Savant, Manisha Parmar, Priti Adlakha, Anamik Shah*

Bioorganic & Medicinal Chemistry Letters doi:10.1016/j.bmcl.2011.02.016

2. Synnthesis of some novel benzofuran-2-yl(4,5-dihyro-3,5-substituted diphenylpyrazol-1-yl) methanones and studies on the antiproliferative effects and reversal of multidruug resistance of human MDR1-gene transfected mouse lymphoma cells in vitro. Shrey Parekh, Dhairya Bhavsar, Mahesh Savant, Shailesh Thakrar, Abhay Bavishi, Manisha Parmar, Hardevsinh Vala, Ashish Radadiya, Nilay Pandya, Juliana Serly, Joseph Molnár, Anamik Shah* Euuropean Journal of Medicinal Chemistry, Volume 46, Issue 5, May 2011, Pagees 1942-1948

3. Synnthesis and In Vitro anti-HIV Activity of N-1,3-benzo[d]thiazol-2-yl-2-(2- oxo-2H-chromen-4-yl) Acetamide Derivatives using MTT method. Dhairya Bhavsar, Jalpa Trivedi, Shrey Parekh, Mahesh Savant, Shailesh Thakrar, Abhay Bavishi, Ashish Radadiya, Hardev Vala, Manisha Parmar, Roberta Loddo, Anamik Shah* Bioorganic & Medicinal Chemistry Letters. doi:10.1016//j.bmcl.2011.03.105.

4. An efficient and rapid synthesis of highly functionalizeed novel symmmetric 1,4-dihydropyrridines usinng glacial acetic acid as solvent. Shailesh Thakrar, Abhay Bavishi, Dhairya Bhavsar, Shrey Parekh, Hardev Vala, Ashish Radadiya, Manisha Parmar, Mahesh Savant, Nilay Pandya and Anamik Shah* Synthetic Communication (Accepted).

5. Microwave assisted rapid Synthesis of novel 1,5-benzodiazepines derivatives as potent antimicrobial agent.

Shailesh Thakrar, Abhay Bavishi, Shrey Parekh, Dhairya Bhavsar, Hardevsinh Vala, Ashish Radadiya, Manisha Parmar, Nilay Pandya and Anamik Shah* Joournal of heterocyclic chemistry (Accepted)

Department of Chemistry, Saurashtra University, Rajkot-360005