Synthesis of Heterocyclic Molecules As Potential Anti-Alzheimeric Agents
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SYNTHESIS OF HETEROCYCLIC MOLECULES AS POTENTIAL ANTI-ALZHEIMERIC AGENTS Thesis Submitted in fulfillment for the requirement of the Degree of DOCTOR OF PHILOSOPHY By DEEPAK MISHRA Department of Pharmacy JAYPEE UNIVERSITY OF INFORMATION TECHNOLOGY WAKNAGHAT, DISTRICT SOLAN, H.P., INDIA May 2018 Copyright @ JAYPEE UNIVERSITY OF INFORMATION TECHNOLOGY WAKNAGHAT May, 2018 ALL RIGHTS RESERVED ii Dedicated To My family iii DECLARATION I hereby declare that the work reported in the Ph.D. thesis entitled “SYNTHESIS OF HETEROCYCLIC MOLECULES AS POTENTIAL ANTI- ALZHEIMERIC AGENTS” submitted at Jaypee University of Information Technology, Waknaghat, India, is an authentic record of my work carried out under the joint guidance and supervision of Dr. Chittaranjan Rout, Associate professor, Department of Biotechnology & Bioinformatics, Jaypee University of Information Technology, Waknaghat, Himachal Pradesh and Dr. Ram Singh, Assistant Professor, Department of Applied Chemistry, Delhi Technological University (DTU), Delhi, India. This thesis is a presentation of my original research work. Wherever contributions of others are involved, every effort has been made to indicate this clearly. I have not submitted this work elsewhere for any other degree or diploma. I am fully responsible for the contents of my Ph.D. Thesis. Deepak Mishra Department of Pharmacy Jaypee University of Information Technology, Waknaghat, India Date iv SUPERVISOR’S CERTIFICATE This is to certify that the work reported in the Ph.D. thesis entitled “SYNTHESIS OF HETEROCYCLIC MOLECULES AS POTENTIAL ANTI- ALZHEIMERIC AGENTS”, submitted by Deepak Mishra at Jaypee University of Information Technology, Waknaghat, India, is a bonafide record of his original work carried out under our supervision. This work has not been submitted elsewhere for any other degree or diploma. Supervisor(s) Late Dr Chittaranjan Rout Dr Ram Singh Department of Biotechnology & Bioinformatics, Department of Applied Chemistry Jaypee University of Information Technology, Delhi Technological University Waknaghat, Bawana Road Himachal Pradesh-173234 Delhi - 110042 Dr Gopal Singh Bisht (Administrative Supervisor) Department of Biotechnology & Bioinformatics, Jaypee University of Information Technology, Waknaghat, Himachal Pradesh-173234 v ACKNOWLEDGEMENTS It is my great pleasure to express my profound gratitude to my supervisors, Dr. Chittaranjan Rout, Department of Biotechnology & Bioinformatics, Jaypee University of Information technology, Waknaghat, Himachal Pradesh and Dr. Ram Singh, Department of Applied Chemistry, Delhi Technological University, Delhi, for their guidance, constant inspiration and valuable suggestions for carrying out this work. The discussions held with them were very enlightening and always motivated me to work with greater zeal and enthusiasm. Thanks are also due to Dr. Richa Srivastava, Department of Applied Chemistry, Delhi Technological University, Delhi and Dr. Geetanjali,, Kirori Mal College, University of Delhi, Delhi for their constant guidance and inspiration. I would like to express my profound gratitude to Dr. Sudhir Kumar, Head of the Department, Department of Biotechnology & Bioinformatics, and all former heads, JUIT administration and DTU administration under whom I worked for helping me in the related problems during the entire duration of my PhD work. I also convey my sincere thanks to all faculty members and DPMC members of JUIT and all faculty members of DTU for their active support. When one owes to so many, it is almost impossible and invidious to single out names. However I acknowledge my friends for their patience and active support. I also thank them for keeping me cheerful throughout entire period of work. I was fortunate to have an excellent work environment in the laboratory which facilitated my work to a great deal. I must thank Dr. Atiya Fatima, Geetika Bhasin, Babita Veer, Poonam, Aradhna Sharma, Shankar Suman, Yogesh Khairnar, Vineet Mehta, and Nupur for their constant help in every possible way to carry forward my research work. I am also grateful to technical and non-technical staff of Department of Biotechnology & Bioinformatics, Jaypee University of Information technology and Department of Applied Chemistry, Delhi Technological University, for their timely support and cooperation during my thesis work. At last but not least, I would like to express my profound gratitude to University Grants Commission, New Delhi for giving me fellowship through CSIR-UGC JRF fellowship scheme. I would also like to thank Council of Scientific and Industrial research, New Delhi for funding the research as this work is a part of CSIR project. Deepak Mishra vi TABLE OF CONTENTS LIST OF FIGURES ix LIST OF SCHEMES xii LIST OF TABLES xiii ABBRIVIATIONS xiv ABSTRACT xv CHAPTER 1: ALZHEIMER’S DISEASE: TREATMENT AND 1-22 DEVELOPMENT OF NOVEL LEAD MOLECULES 1.1 Introduction 1.2 History of Alzheimer disease (AD) 1.2.1 Disease process 1.2.2 Diagnosis and treatments 1.2.3 Cholinergic hypothesis for Alzheimer disease (AD) 1.2.4 Amyloid hypothesis for Alzheimer disease (AD) 1.2.5 MAO hypothesis of Alzheimer disease (AD) 1.2.6 Current therapies for AD 1.3 Synthetic compounds as cholinesterase inhibitors 1.3.1 Tacrine and its derivatives 1.3.2 Tacrin-phenylthiazole hybrids 1.3.3 Coumarins derivatives 1.4 Computational Approaches for Lead Discovery 1.4.1 Geometry optimization 1.4.2 Docking methods to identify binding interactions modes of the ligand 1.5 Objectives CHAPTER 2: DESIGN, SYNTHESIS AND EVALUATION OF 3-[2-(4- 23-50 PHENYLTHIAZOL-2-YLAMINO)ACETYL]CHROMEN-2-ONE DERIVATIVES AS CHOLINESTERASE INHIBITORS 2.1 Introduction 2.2 Experimental 2.2.1 Preliminary in-silico interaction studies of coumarin- thiazole conjugates 2.2.2 Synthesis of 3-[2-(4-phenylthiazol-2-ylamino)acetyl] chromen-2-one derivatives (8a-l) 2.2.3 In- silico (Docking) studies 2.2.4 In-vitro studies 2.3 Results and discussion 2.3.1 Synthesis and characterization of 3-[2-(4-phenylthiazol-2- ylamino)acetyl]chromen-2-one derivatives vii 2.3.2 In-silico interaction analysis 2.3.3 In-vitro inhibition studies of AChE & BuChE CHAPTER 3: DESIGN, SYNTHESIS AND EVALUATION OF N- 51-86 BENZOTHIAZOL-2-YL-2-(3-MERCAPTO-5-PHENYL-[1,2,4] TRIAZOL- 4-YLAMINO)ACETAMIDE DERIVATIVES AS CHOLINESTERASE INHIBITORS 3.1 Introduction 3.2 Experimental 3.2.1 Preliminary in silico interaction studies of benzothiazole and triazole moieties with AChE and BuChE 3.2.2 Synthesis of N-benzothiazol-2-yl-2-(3-mercapto-5-phenyl- [1,2,4]triazol-4-ylamino) acetamide derivatives (16a-i) 3.2.3 In silico (Docking) studies 3.2.4 In-vitro experimental studies 3.3 Results and discussion 3.3.1 Synthesis of N-benzothiazol-2-yl-2-(3-mercapto-5-phenyl- [1,2,4]triazol-4-ylamino)-acetamide derivatives 3.3.2 In-silico interaction studies 3.3.3 In-vitro inhibition studies of AChE & BuChE CHAPTER 4: DESIGN, SYNTHESIS AND EVALUATION OF N-(3- 87-106 MERCAPTO-5-PHENYL-4H-1,2,4-TRIAZOLE-4-YL)-2-OXO-2H- CHROMENE-3-CARBOXAMIDE DERIVATIVES AS CHOLINESTERASE INHIBITORS 4.1. Introduction 4.2. Experimental 4.2.1 Preliminary in-silico studies of coumarin-triazole conjugates 4.2.2 Synthesis of N-(3-mercapto-5-phenyl-4H-1,2,4-triazole-4- yl)-2-oxo-2H-chromene-3-carboxamide derivatives 4.2.3 In- silico (Docking) studies 4.2.4 In-vitro experimental studies 4.3. Results and discussion 4.3.1 Synthesis of N-(3-mercapto-5-phenyl-4H-1,2,4-triazole-4- yl)-2-oxo-2H-chromene-3-carboxamide derivatives 4.3.2 In-silico interaction studies 4.3.3 In-vitro inhibition studies of AChE & BuChE CHAPTER 5: CONCLUSION AND FUTURE PROSPECTS 107-110 REFERENCES 111-133 PUBLICATIONS 134 viii LIST OF FIGURES Figure No. Title Figure 1.1 Prevalence of individual with dementia by age and gender in India Figure 1.2 Number of individual with dementia by age, 2010-2050 Figure 1.3 Amyloid Plaques and Neurofibrillary tangles Figure 1.4 Structure of brain at the different stages of Alzheimers disease Figure 1.5 Acetylcholinesterase/ Butyrylcholinesterase hydrolysing acetylcholine Figure 1.6 Oxidative deamination of amines by MAO proteins Figure 1.7 Tacrine molecule Figure 1.8 Phenylthiazole-tacrine conjugates Figure 1.9 Phenylthiazole-tacrine conjugates Figure 1.10 Ensaculin, KA-672 Figure 1.11 AP2238 and its derivatives Figure 1.12 Coumarin derivatives Figure 2.1 Structure of benzopyran derivatives Figure 2.2 Potential medicinal applications of coumarins Figure 2.3 Classification of coumarins Figure 2.4 Potential interaction between AChE with coumarin-thiazole conjugate Figure 2.5 Flow chart indicating design, synthesis and evaluation of coumarin-thiazole as conjugates as cholinesterase inhibitors Figure 2.6 1H NMR spectrum of 3-acetyl-2H-chromen-2-one (3) Figure 2.7 13C NMR spectrum of 3-acetyl-2H-chromen-2-one (3) Figure 2.8 1H NMR spectrum of 3-(2-bromoacetyl)chromen-2-one (4a) Figure 2.9 1H NMR spectrum of 3-(2,2-dibromoacetyl)chromen-2-one (4b) 1 Figure 2.10 H NMR spectrum of 4-phenyl-1,3-thiazol-2-amine (7a) Figure 2.11 Expansion 1H NMR spectrum of 4-phenyl-1,3-thiazol-2-amine (7a) ix Figure 2.12 FTIR spectrum of 3-[2-(4-phenylthiazol-2-ylamino)acetyl]chromen-2-one (8a) Figure 2.13 1H NMR spectrum of 3-[2-(4-phenylthiazol-2-ylamino)acetyl]chromen-2- one (8a) Figure 2.14 13C NMR spectrum of 3-[2-(4-phenylthiazol-2-ylamino)acetyl]chromen-2- one (8a) Figure 2.15 Interaction of 3-{2-[4-(3-Nitrophenyl)thiazol-2-ylamino]acetyl}chromen-2- one (8j) with active site of BuChE IC value in μM concentration of for AChE enzyme (3, 4, 7a-7l and 8a-l). Figure 2.16 50 IC50 value less than 100 μM concentration is considered significant inhibition; therefore, most of the compounds are inactive against AChE enzyme. Figure 2.17 IC50 value in μM concentration of for BuChE enzyme (3, 4, 7a-l and 8a-l, Scheme 2.1).