Synthesis, Antibacterial and Antifungal Activities of Some New Azo Anils Containing Pyrazole Moiety

Indian Journal of Chemistry Vol. 53B, February 2014, pp 227-237

Synthesis, antibacterial and antifungal activities of some new azo anils containing pyrazole moiety

S Sharma*a, Jasvir Kaurb, Sandeep Kaurb & Poonam Sharmaa aDepartment of Plant Breeding & Genetics, Punjab Agricultural University, Ludhiana 141 004, India bDepartment of Chemistry, Punjab Agricultural University, Ludhiana 141 004, India E-mail: [email protected] Received 11 February 2013; accepted (revised) 31 October 2013

A series of azo compounds namely 3-(Phenylazo) benzaldehyde 1a-f, 3-(4-Nitrophenylazo) benzaldehyde 3a-f and 3- (1,5-Dimethyl–3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl-azo) benzaldehyde 6 were synthesized and then azo anils viz. 3-(Phenylazo)-1,5 dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H pyrazol-4-yl imino methyl benzene 2a-f, 4a-f and 7-9 have been synthesized from azo compounds by reacting with corresponding amines. All the compounds synthesized by conventional method are also prepared by using microwave irradiation method and are characterized by spectroscopic techniques (UV, FTIR and 1H NMR). The synthesized compounds have been screened for antimicrobial activity against bacteria viz. Mesorhizobium sp., Bacillus sp. and Pseudomonas sp., fungus (Ascochyta blight) and yeast (Sacchromycis cerevisiae). The azo anils show minor to moderate activity against bacteria and no activity against fungus and yeast. The activity shown by some compounds is due to substitution of chloro, methoxy or nitro group on phenyl ring or due to some heterocyclic moiety. Keywords: Azo anils, azo compounds, microwave irradiation, Mesorhizobium sp., Bacillus sp., Pseudomonas sp.

Azo anil formation is of major importance in and pharmaceutical chemistry with several biological biological processes as many of these involve the applications. It has been suggested that azomethine initial binding of carbonyl compounds to an enzyme linkage might be responsible for the biological through imine formation. Among the organic reagents activities of Schiff bases. Therefore, in the present actually used, imines possess excellent characteristics, study, some new azoanils with azomethine linkage structural similarities with natural biological have been synthesized by conventional and substances, relatively simple preparation procedure microwave methods and evaluated for their microbial and synthetic flexibility that enables design of suitable studies. structural properties. Carbon-nitrogen double bond is widely distributed in nature, in the form of biological Results and Discussion compounds which are important for the vital Synthesis of azo compounds 1a-f was carried out metabolism of the living organisms and in various by the reaction of diazonuim salt of aniline with synthetic compounds of pharmaceutical and benzaldehyde, 2-methoxy benzaldehyde, 4-methoxy agricultural importance. Azo dyes constitute one of benzaldehyde, 2-chlorobenzaldehyde, 4-chlorobenz- the largest and most varied groups of synthetic aldehyde and 3-nitrobenzaldehyde respectively organic dyes in use today1. Azo compounds are highly (Scheme I). The physical data of azo compounds and important, well known and widely used substances in azo anils is given in Table I. The structure of these the textile, paper, colouring agents for foods and compounds were confirmed by FTIR spectroscopy cosmetics industries2,3. Furthermore, azo compounds that recorded peaks between 1410-1417 cm-1 due to were reported to show a variety of biological N=N stretching. These azo compounds were reacted activities including antibacterial4, antifungal5, with 4-aminophenazone and respective azo anils 2a-f pesticidal, antiviral and anti inflammatory activities. were formed (Scheme I) that was characterized by Azomethine function is endowed with multiform UV-visible, FTIR and 1H NMR spectroscopy. UV- reactivity and particularly is able to react with thiol visible spectra recorded λmax between 267-293 and groups, thus it can establish easily some kind of link 338-357 nm, FTIR spectra recorded peaks between with enzymatic or receptorial proteins. Schiff bases 1660-1678 cm-1 due to C=N and 1413-1459 cm-1 due form a significant class of compounds in medicinal to N=N stretching. 1H NMR spectra showed a singlet 228 INDIAN J. CHEM., SEC B, FEBRUARY 2014

Scheme I between δ 8.09-8.35 due to hydrogen of HC=N group. between 260-298 and 330-389 nm, FTIR spectra Similarly the azo compounds 3a-f were prepared by showed peaks between 1660-1671 cm-1 due to C=N the reaction of diazonium salt of 4-nitro aniline with and 1405-1459 cm-1 due to N=N stretching and 1H respective aldehydes viz. benzaldehyde, 2-methoxy NMR spectra recorded a singlet between δ 8.11-8.35 benzaldehyde, 4-methoxy benzaldehyde, 2-chloro- due to hydrogen of HC=N group. An azo compound 6 benzaldehyde, 4-chlorobenzaldehyde and 3-nitrobenz- was prepared from the diazonium salt of aldehyde (Scheme II). The structure of these 4-aminophenazone and benzaldehyde (Scheme III). compounds were confirmed by FTIR spectroscopy The structure of this compound was confirmed by that recorded peaks between 1409-1415 cm-1 due to FTIR spectroscopy that recorded a peak at 1410 cm-1 N=N stretching. Then these synthesized azo due to N=N stretching. It was reacted with different compounds were reacted with 4-aminophenazone and amines like aniline, 4-nitro aniline and respective azo anils 4a-f were formed (Scheme II) 4-aminophenazone to obtain respective azo anils 7, 8 that was confirmed by using UV-visible, FTIR and 1H and 9 (Scheme IV). The structures of these NMR spectroscopy. UV-visible spectra recorded λmax compounds were characterized by UV-visible, FTIR SHARMA et al.: NEW AZO ANILS 229

Table I — Physical data of synthesized compounds

Compd R R1 R2 Molecular Formula m.p (°C) Yield (%)

C H N O 1a H H H 13 10 2 72-74 72

2a H H H C24H21N5O 142-144 50 C H N O 1b OCH3 H H 14 13 2 2 85-87 80

2b OCH3 H H C25H23N5O2 80-82 75 C H N O 1c H H OCH3 14 13 2 2 93-95 75

2c H H OCH3 C25H23N5O2 85-89 70 C H N OCl 1d Cl H H 13 9 2 100-102 70

2d Cl H H C24H20N5OCl 105-107 67 C H N OCl 1e H H Cl 13 9 2 90-92 70

2e H H Cl C24H20N5OCl 95-97 70 C H N O 1f H NO2 H 13 9 3 3 85-87 80

2f H NO2 H C24H20N6O3 80-82 65 C H N O 3a H H H 13 9 3 3 105-108 70

4a H H H C24H20N6O3 67-69 65 C H N O 3b OCH3 H H 14 11 3 4 140-142 70

4b OCH3 H H C25H22N6O3 152-154 55 C H N O 3c H H OCH3 14 11 3 4 102-106 70

4c H H OCH3 C25H22N6O3 79-81 74 C H N O Cl 3d Cl H H 13 8 3 3 105-107 75

4d Cl H H C24H19N6O3Cl 112-114 72 C H N O Cl 3e H H Cl 13 8 3 3 76-78 70

4e H H Cl C24H19N6O3Cl 85-88 47 C H N O 3f H NO2 H 13 8 4 5 115-120 70

4f H NO2 H C24H19N7O5 79-82 59 C H N O 6 H H H 18 16 4 2 87-89 70

7 H H H C24H21N5O 92-95 65

8 H H H C24H20N6O3 120-124 65

9 H H H C26H21N7O5 106-108 55 and 1H NMR spectroscopy. UV-visible spectra about 5-30% increase in yield in case of microwave recorded λmax between 273-298 and 332-375 nm, irradiation method (Table II). FTIR spectra recorded peaks between 1660-1676 cm-1 due to C=N and 1400-1412 cm-1 due to N=N Antimicrobial testing stretching. 1H NMR spectra showed a singlet between The synthesized compounds 2a-f, 4a-f, 7-9 were δ 7.80-8.28 due to hydrogen present on HC=N group. screened for their inhibitory effect on the growth of The synthesized azo anils were purified by bacteria (Mesorhizobium sp., Bacillus sp. and recrystallization and the purity of compounds was Pseudomonas sp.), fungus (Ascochyta blight) and checked by thin layer chromatography. yeast (Sacchromycis cerevisiae) at various Azo anils synthesized by conventional method concentrations. were also prepared by using microwave irradiation method from the azo compounds synthesized by Anti-bacterial activity conventional method6. It was observed that the The results shown in Tables III, IV and V revealed reaction completed in maximum 10 minutes by that the majority of synthesized compounds exhibited microwave irradiation method which was completed varying degrees of inhibition against the in 9 hr in case of conventional method and there was Mesorhizobium sp., Bacillus sp. and Pseudomonas sp. 230 INDIAN J. CHEM., SEC B, FEBRUARY 2014

Scheme II

The compounds 2a, 2c, 2f, 4b, 4d, 4e, 4f, and 9 group on phenyl ring were effective against all the containing pyrazole moiety having no substitution on tested bacteria. Compound 2d having 2-chloro group phenyl ring exhibited no activity against tested on phenyl ring was found effective against Bacillus bacteria even upto 5000 µg/mL concentration. and Pseudomonas sp. The data revealed that Compound 2a without any substitution on phenyl ring compounds 7 and 8 were not effective against was effective against Bacillus sp. only at 4000 and Bacillus sp. upto 5000 µg/mL concentration. While 5000 µg/mL concentration. This compound exihibited the compound 7 showed activity against no activity against Mesorhizobium sp. and Pseudomonas sp. and the compound 8 exhibited some Pseudomonas sp. upto 5000 µg/mL concentration. activity against Mesorhizobium sp. However all Compounds containing 2-methoxy 2b and 4-chloro 2e compounds were less effective as compared to SHARMA et al.: NEW AZO ANILS 231

Scheme III streptomycin. So overall it was revealed that the azo Experimental Section anils containing pyrazole moiety and having no Melting points were determined using open substitution on phenyl ring showed no inhibition of capillaries method and are uncorrected. The UV the tested bacteria. The compounds that showed some spectra of synthesized azo anils were recorded on UV inhibition, was due to the presence of substitution of 2600 spectrophotometer using acetonitrile as solvent. chloro, methoxy or nitro group on some positions of The IR spectra of compounds were recorded using the phenyl ring. KBr discs on Perkin-Elmer FTIR spectrophotometer -1 1 with λmax in cm and H NMR spectra were recorded Anti-fungal activity on a Bruker Avance II 400 MHz instrument using All the compounds were found ineffective against TMS as an internal standard. The chemical shifts are ׳s׳ fungus (Ascochyta blight) and yeast (Sacchromycis expressed in δ (ppm) values and the abbreviations .stand for singlet and multiplet respectively ׳m׳ cerevisiae). The compounds recorded zero inhibition and zone upto 5000 µg/mL concentrations. All the compounds gave satisfactory C, H and N 232 INDIAN J. CHEM., SEC B, FEBRUARY 2014

Scheme IV analysis that was recorded on Vario EL III Elementar dichloromethane (20 mL). The solvent was CHNS analyser. The purity of compounds was evaporated under reduced pressure on rotary vacuum checked on silica gel G coated TLC plates. The evaporator. The crude product was purified by visualization of spots was done in an iodine chamber. recrystallisation from 95% ethanol to furnish the corresponding azo compound. The purity of the General procedure for the synthesis of azo compound was checked by thin layer compounds 1a-f, 3a-f, 6 chromatography. Azo compounds were synthesized according to Jorrahpour et al6. General procedure for the synthesis of azo anils Substituted aldehyde (0.01 mol) was dissolved in 2a-f, 4a-f, 7-9 aqueous 2 M NaOH (10 mL) and the resulting Conventional method solution was added slowly to a solution of substituted 4-Aminophenazone (0.01 mol) and anhydrous benzene diazonium chloride (0.01mol) at 3°C sodium sulphate (15 g) were added to a stirred temperature. The reaction mixture was stirred for 1 hr solution of azo compound (0.01 mol) in at 3°C and then allowed to warm up slowly to RT. dichloromethane (30 mL) at 3°C. The resulting The dark brown coloured precipitates obtained were mixture was stirred for another 8 hr at RT then filtered and partitioned between water (20 mL) and filtered and solvent was evaporated. It gave azo anil SHARMA et al.: NEW AZO ANILS 233

Table II — Comparison of conventional and MW methods used for azo anil synthesis

Compd Yield (%) Time*taken in MW Conventional Microwave Increase in method (min) method method yield (%)

2a 50 75 15 5 2b 75 60 15 7 2c 70 80 10 9 2d 67 75 8 4 2e 70 75 5 6 2f 65 80 15 5 4a 65 75 10 7 4b 55 85 30 7 4c 74 87 13 6 4d 72 80 8 4 4e 47 77 30 10 4f 59 70 11 3 7 65 70 5 10 8 65 80 15 6 9 55 80 25 9 The product yield increased by 5-30% with the use of MW irradiation method. *The completion of the reaction took 9 hr in conventional method.

Table III — Microbial activity of different azo anils on the growth of Mesorhizobium sp. (LGR-33)

Compd Diameter of growth inhibition zone (mm) 5000 4000 3000 2000 1000 500 250 125 µg/mL µg/mL µg/mL µg/mL µg/mL µg/mL µg/mL µg/mL

2a 0 0 0 0 0 0 0 0 2b 9 8 7 7 6 6 6 5 2c 0 0 0 0 0 0 0 0 2d 0 0 0 0 0 0 0 0 2e 8 8 7 6 6 5 5 4 2f 0 0 0 0 0 0 0 0 4a 0 0 0 0 0 0 0 0 4b 0 0 0 0 0 0 0 0 4c 0 0 0 0 0 0 0 0 4d 0 0 0 0 0 0 0 0 4e 0 0 0 0 0 0 0 0 4f 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 8 10 10 10 9 7 7 6 5 9 0 0 0 0 0 0 0 0 Streptomycin 21 19 18 17 16 15 13 12 which was purified by recrystallisation from 95% Biological study ethanol. The purity of the compound was checked by The newly synthesized azo anils 2a-f, 4a-f, 7, 8 and thin layer chromatography. 9 were evaluated for their microbial activity against bacteria viz. Mesorhizobium sp., Bacillus sp. and Microwave irradiation method Pseudomonas sp. and fungus viz. Ascochyta blight Conventionally prepared azo compound (0.01 mol) and yeast (Sacchromyces cerevisiae). was mixed with corresponding amine (0.01 mol) in a beaker with the help of a glass rod and the mixture Bacterial activity was irradiated in microwave oven at 360 W for The effect of azo anil derivatives on the growth of different time interval. The progress of reaction was bacteria viz. Mesorhizobium sp., Bacillus sp. and checked with thin layer chromatography after an Pseudomonas sp. was determined using bacterial interval of one or two minutes. After the completion sensitivity-filter paper disc method7. The plates were of reaction, the product was recrystalised from prepared by pouring 15-20 mL of the sterilized ethanol to afford the corresponding azo anils. CRYEMA (for Mesorhizobium sp.), nutrient agar 234 INDIAN J. CHEM., SEC B, FEBRUARY 2014

Table IV — Microbial activity of different azo anils on the growth of Bacillus sp. (BSY-101)

Compd Diameter of growth inhibition zone (mm) 5000 4000 3000 2000 1000 500 250 125 µg/mL µg/mL µg/mL µg/mL µg/mL µg/mL µg/mL µg/mL

2a 10 7 0 0 0 0 0 0 2b 13 12 11 9 7 0 0 0 2c 0 0 0 0 0 0 0 0 2d 15 13 11 10 10 8 5 5 2e 11 9 6 5 3 0 0 0 2f 0 0 0 0 0 0 0 0 4a 0 0 0 0 0 0 0 0 4b 0 0 0 0 0 0 0 0 4c 12 11 9 7 0 0 0 0 4d 0 0 0 0 0 0 0 0 4e 0 0 0 0 0 0 0 0 4f 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 Streptomycin 21 19 18 17 16 15 13 12

Table V — Microbial activity of different azo anils on the growth of Pseudomonas sp. (LK-791)

Compd Diameter of growth inhibition zone (mm) 5000 µg/mL 4000 µg/mL 3000 µg/mL 2000 µg/mL 1000 µg/mL 500 µg/mL 250 µg/mL 125 µg/mL

2a 0 0 0 0 0 0 0 0 2b 9 9 7 7 6 0 0 0 2c 0 0 0 0 0 0 0 0 2d 8 7 7 6.5 6 0 0 0 2e 10 8 7 7 5 0 0 0 2f 0 0 0 0 0 0 0 0 4a 0 0 0 0 0 0 0 0 4b 0 0 0 0 0 0 0 0 4c 0 0 0 0 0 0 0 0 4d 0 0 0 0 0 0 0 0 4e 0 0 0 0 0 0 0 0 4f 0 0 0 0 0 0 0 0 7 10 9 7.5 7 7 6 6 0 8 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 Streptomycin 16 15 15 14 13 13 12 11 media (for Bacillus sp.) and King’s B media zone (mm) was measured after 24 hr. The growth of (for Pseudomonas sp.) in sterilized petriplates. Plates the organism on the plates containing the test were then allowed to solidify and stored for two days compound was also compared with the growth of to ensure sterility. Suspension of 3-4 days old broth of bacteria on plates served as control. the test organism (Mesorhizobium sp., Bacillus sp. and Pseudomonas sp.) was then spread on the Fungal activity required medium plates. Sterile filter paper discs The effect of synthesized azo anil derivatives on moistened with test compound solution in water were the growth of fungus Ascochyta blight was carefully placed on plates inoculated with the determined using bit method8. The plates were respective bacterial suspension under aseptic prepared by pouring 15-20 mL of the sterilized potato conditions. Sterilized filter paper discs dipped in dextrose agar (PDA) media on sterilized petriplates. water served as control. Plates were incubated at Plates were then allowed to solidify and stored for 28°C ± 1°C and the diameter of growth inhibition two days to ensure sterility. Then a bit was cut with SHARMA et al.: NEW AZO ANILS 235

the help of a bit cork from media plate on which 5-(Phenylazo)-2-methoxy-1,5-dimethyl-3-oxo-2- fungus was already grown and placed in the centre of phenyl-2,3-dihydro-1H pyrazol-4-yl imino methyl the media plates. Sterile filter paper discs moistened benzene, 2b: UV-visible (λmax) 278 and 345 nm; IR with test compound solution in water were carefully (KBr): 3060 (Ar C-H), 1671 (C=N ),1652 (C=C ), -1 1 placed on the medium under aseptic conditions. Plates 1650(C=O) and 1414 cm (N=N); H NMR (CDCl3): were incubated at 22°C ± 1°C and the diameter of δ 2.03 (s, 3H, CH3), 2.73 (s, 3H, CH3), 3.84 (s, 3H, growth inhibition zone (mm) was measured after OCH3), 7.12-7.40 (m, 13Ar-H) and 8.25 24 hr. The growth of the organism on medium (s, 1H, HC=N). Anal. Calcd for C25H23N5O2: C, containing the test compound was also compared with 70.59; H, 5.41; N, 15.49. Found: C, 70.57; H, 5.40; N, the growth on the plate containing filter paper disc 15.47%. moistened with water that served as control. 4-Methoxy-5-(phenylazo) benzaldehyde, 1c: IR (KBr): 3050 (Ar C-H), 2930 (C-H), 1710 (C=O), -1 Yeast activity 1649 (C=C), 1417 (N=N), 1378 (C-N) and 1305 cm The synthesized azo anil derivatives were also (C-O). Anal. Calcd for C14H13N2O2: C, 69.71; H, 5.39; tested for their effect on growth of yeast N, 11.62. Found: C, 69.68; H, 5.37; N, 11.60%. (Sacchromyces cerevisiae) by filter paper disc 5-(Phenylazo)-4-methoxy-1,5-dimethyl–3–oxo-2- H method. The plates were prepared by pouring 15-20 phenyl-2,3-dihydro-1 pyrazol-4-yl imino methyl λ mL of the sterilized glucose yeast extract (GYE) benzene, 2c: UV-visible ( max) 272 and 342 nm; IR (KBr): 3050 (Ar C-H), 1660 (C=N), 1650 (C=C ), media on sterilized petriplates and after solidifying at -1 1 room temperature, the plates were stored for two days 1654 (C=O) and 1459 cm (N=N); H NMR (CDCl3): δ to ensure sterility. Suspension of 3-4 days old broth of 2.47 (s, 3H, CH3), 3.11 (s, 3H, CH3), 3.85 (s, 3H, yeast was then spread on the medium plates. Sterile OCH3), 7.17-7.48 (m, 13Ar-H) and 8.11 (s, 1H, filter paper discs moistened with test compound HC=N). Anal. Calcd for C25H23N5O2: C, 70.59; H, solution in water were placed on the medium under 5.41; N, 15.49. Found: C, 70.57; H, 5.38; N, 15.48%. aseptic conditions. Sterilized filter paper discs dipped 2-Chloro-5-(phenylazo) benzaldehyde, 1d: IR (KBr): 3055 (Ar C-H), 2933 (C-H), 1710 (C=O), in water served as control. Plates were incubated at 1649 (C=C), 1415 (N=N), 1376 (C-N) and 1190 cm-1 28°C ± 1°C and the diameter of growth inhibition (C-Cl). Anal. Calcd for C13H9N2OCl: C, 63.80; H, zone (mm) was measured after 24 hr. The growth of 3.68; N, 11.45. Found: C, 63.78; H, 3.66; N, 11.43%. the organism was also compared with the growth on 5-(Phenylazo)-2-chloro-1,5-dimethyl-3-oxo-2- the plates served as control. phenyl-2,3-dihydro-1H pyrazol-4-yl imino methyl benzene, 2d: UV-visible (λmax) 270 and 343 nm; IR Compounds 1a-f, 2a-f (KBr): 3055 (Ar C-H), 1672 (C=N), 1655 (C=C), -1 1 3-(Phenylazo) benzaldehyde, 1a: IR (KBr): 3065 1668 (C=O) and 1414 cm (N=N); H NMR (CDCl3): (Ar C-H), 2932 (C-H), 1710 (C=O), 1650 (C=C), δ 1.98 (s, 3H, CH3), 2.68 (s, 3H, CH3), 7.09-7.37 -1 1415 (N=N) and 1380 cm (C-N). Anal. Calcd for (m, 13Ar-H) and 8.21 (s, 1H, HC=N). Anal. Calcd for C13H10N2O: C, 74.29; H, 4.76; N, 13.33. Found: C24H20N5OCl: C, 67.05; H, 4.66; N, 16.30. Found: C, 74.27; H, 4.75; N, 13.30%. C, 67.04; H, 4.64; N, 16.28%. 3-(Phenylazo)-1,5 dimethyl-3-oxo-2-phenyl-2,3 4-Chloro-5-(phenylazo)benzaldehyde, 1e: IR dihydro-1H pyrazol-4-yl imino methyl benzene, 2a: (KBr): 3055 (Ar C-H), 2935 (C-H), 1710 (C=O), -1 UV-visible (λmax) 293 and 357 nm; IR (KBr): 3065 1650 (C=C), 1410 (N=N), 1380 (C-N) and 1180 cm (Ar C-H), 1678 (C=N), 1652 (C=C), 1650 (C=O) and (C-C). Anal. Calcd for C13H9N2OCl: C, 63.80; H, -1 1 1413 cm (N=N); H NMR (CDCl3): δ 2.03 3.68; N, 11.45. Found: C, 63.77; H, 3.66; N, 11.42%. (s, 3H, CH3), 2.83 (s, 3H, CH3), 7.10-7.75 5-(Phenylazo)-4-chloro-1,5-dimethyl-3-oxo-2- (m, 14Ar-H) and 8.09 (s, 1H, HC=N). Anal. Calcd for phenyl-2,3-dihydro-1H pyrazol-4-yl imino methyl C24H21N5O: C, 72.91; H, 5.32; N, 17.72. Found: benzene, 2e: UV-visible (λmax) 267 and 338 nm ; IR C, 72.90; H, 5.31; N, 17.70%. (KBr): 3055 (Ar C-H), 1665 (C=N), 1654 (C=C), -1 1 2-Methoxy-5-(phenylazo) benzaldehyde, 1b: IR 1651(C=O) and 1456 cm (N=N); H NMR (CDCl3): (KBr): 3050 (Ar C-H), 2930 (C-H), 1710 (C=O), δ 2.09 (s, 3H, CH3), 2.89 (s, 3H, CH3), 7.18-7.43 1649 (C=C), 1417 (N=N), 1378 (C-N ) and 1305 cm-1 (m, 13Ar-H) and 8.35 (s, 1H, HC=N). Anal. Calcd for (C-O). Anal. Calcd for C14H13N2O2: C, 69.71; H, 5.39; C24H20N5OCl: C, 67.05; H, 4.66; N, 16.30. Found: N, 11.62. Found: C, 69.70; H, 5.36; N, 11.60%. C, 67.03; H, 4.63; N, 16.28%. 236 INDIAN J. CHEM., SEC B, FEBRUARY 2014

3-Nitro-5-(phenylazo) benzaldehyde, 1f: IR 5-(4-Nitrophenyl)-4-methoxy-1, 5-dimethyl-3-oxo- (KBr): 3062 (Ar C-H), 2938 (C-H), 1710 (C=O), 2-phenyl-2,3 dihydro-1H pyrazol-4-yl imino -1 1652 (C=C), 1410 (N=N) and 1298 cm (N=O). Anal. methyl benzene, 4c: UV-visible (λmax): 291 and 332 Calcd for C13H9N3O3: C, 61.17; H, 3.53; N, 16.47. nm ; IR (KBr): 3055 (Ar C-H), 1672 (C=N), 1655 Found: C, 61.15; H, 3.50; N, 16.45%. (C=C), 1668 (C=O), 1414 (N=N) and 1302 cm-1 1 5-(Phenylazo)-3-nitro-1,5-dimethyl-3-oxo-2-phenyl- (N=O); H NMR (CDCl3): δ 1.98 (s, 3H, CH3), 2.68 2,3-dihydro-1H pyrazol-4-yl imino methyl (s, 3H, CH3), 3.69 (s, 3H, OCH3 ), 7.09-7.37 (m, 12 benzene, 2f: UV-visible (λmax) 271 and 293 nm; IR Ar-H) and 8.21 (s, 1H, HC=N). Anal. Calcd for (KBr): 3062 (Ar C-H), 1678 (C=N), 1652 (C=C), C25H22N6O3: C, 66.08; H, 4.85; N, 18.50. Found: 1650 (C=O), 1413 (N=N) and 1295 cm-1 (N=O ); C, 66.06; H, 4.83; N, 18.48%. 1 H NMR (CDCl3): δ 2.03 (s, 3H, CH3), 2.83(s, 3H, 2-Chloro-3-(4-nitrophenylazo) benzaldehyde, CH3), 7.10-7.75 (m, 13Ar-H) and 8.09 (s, 1H, 3d: IR (KBr): 3050 (Ar C-H), 2930 (C-H), 1705 HC=N). Anal. Calcd for C24H20N6O3: C, 65 CH3.45; (C=O), 1648 (C=C), 1411 (N=N), 1300 (N=O) and -1 H, 4.54; N, 19.09. Found: C, 65.42; H, 4.53; N, 1185 cm (C-Cl). Anal. Calcd for C13H8N3O3Cl: 19.07%. C, 53.88; H, 2.76; N, 14.51. Found: C, 53.86; H, 2.74; Compounds 3a-f, 4a-f N, 14.50%. 3-(4-Nitrophenylazo) benzaldehyde, 3a: IR 5-(4-Nitrophenylazo)-2-chloro-1, 5-dimethyl–3- (KBr): 3060 (Ar C-H), 2932 (C-H), 1700 (C=O), oxo-2-phenyl-2,3-dihydro-1H pyrazol-4-yl imino -1 1656 (C=C), 1410 (N=N), 1310 (C-O) and 1305 cm methyl benzene, 4d: UV-visible (λmax): 292 and 358 (N=O). Anal. Calcd for C13H9N3O3: C, 61.17; H, 3.53; nm ; IR (KBr): 3050 (Ar C-H), 1665 (C=N), 1654 N, 16.47. Found: C, 61.15; H, 3.51; N, 16.44%. (C=C), 1651 (C=O), 1456 (N=N) and 1302 cm-1 1 δ 5-(4-Nitrophenylazo)-1,5-dimethyl-3-oxo-2- (N=O); H NMR (CDCl3): 2.09 (s, 3H, CH3), 2.80 phenyl-2,3-dihydro-1H pyrazol-4-yl imino methyl (s, 3H, CH3), 7.18-7.43 (m, 12Ar-H) and 8.35 (s, 1H, benzene, 4a: UV-visible (λmax): 260 and 330 nm; IR HC=N). Anal. Calcd for C24H19N6O3Cl: C, 60.69; (KBr): 3072 (Ar C-H), 1671 (C=), 1652 (C=C), 1650 H, 4.00; N, 17.70. Found: C, 60.66; H, 3.98; N, (C=O), 1414 (N=N) and 1300 cm-1 (N=O); 1H NMR 17.68%. (CDCl3): δ 2.03 (s, 3H, CH3), 2.73 (s, 3H, CH3), 4-Chloro-3-(4-Nitrophenylazo) benzaldehyde, 7.12-7.40 (m, 13 Ar-H) and 8.25 (s, 1H, HC=N). 3e: IR (KBr): 3055 (Ar C-H), 2930 (C-H), 1700 Anal. Calcd for C24H20N6O3: C, 65.45; H, 4.54; N, (C=O), 1652 (C=C), 1409 (N=N), 1302 (N=O) and -1 19.09. Found: C, 65.43; H, 4.52; N, 19.07%. 1180 cm (C-Cl). Anal. Calcd for C13H8N3O3Cl: 2-Methoxy-3-(4-nitrophenylazo) benzaldehyde, C, 53.88; H, 2.76; N, 14.51. Found: C, 53.86; H, 3b: IR (KBr): 3072 (Ar C-H), 2926 (C-H), 1705 2.743 N, 14.48%. (C=O), 1657 (C=C), 1413 (N=N) and 1306 cm-1 5-(4-Nitrophenylazo)-4-chloro-1,5-dimethyl-3-oxo- H (N=O). Anal. Calcd for C14H11N3O4: C, 58.95; H, 2-phenyl-2,3 dihydro-1 pyrazol-4-yl imino 3.86; N, 14.74. Found: C, 58.93; H, 3.84; N, 14.72%. methyl benzene, 4e: UV-visible (λmax): 291 and 342 5-(4-Nitrophenylazo)-2-methoxy-1,5-dimethyl-3- nm ; IR (KBr): 3055 (Ar C-H), 1670 (C=N), 1654 oxo-2-phenyl-2,3-dihydro-1H pyrazol-4-yl imino (C=C), 1661 (C=O), 1405 (N=N), 1308 (N=O) and -1 1 δ methyl benzene, 4b: UV-visible (λmax): 298 and 345 1182 cm (C-Cl); H NMR (CDCl3): 2.06 (s, 3H, nm ; IR (KBr): 3060 (C-H), 1660 (C=N),1650 (C=C), CH3), 2.77 (s, 3H, CH3), 7.06-7.45 (m, 12Ar-H), 8.31 -1 1654 (C=O), 1459 (N=N) and 1300 cm (N=O); (s, 1H, HC=N). Anal. Calcd for C24H19N6O3Cl: C, 1 H NMR (CDCl3): δ 2.47 (s, 3H, CH3), 3.11 (s, 3H, 60.69; H, 4.00; N, 17.70. Found: C, 60.67; H, 3.98; N, CH3), 3.85 (s, 3H, OCH3), 7.17-7.48 (m, 12 Ar-H) and 17.67%. 8.11 (s, 1H, HC=N). Anal. Calcd for C25H22N6O3: 3-Nitro-3-(4-nitrophenylazo) benzaldehyde, 3f: C, 66.08; H, 4.85; N, 18.50. Found: C, 66.05; H, 4.84; IR (KBr): 3060 (Ar C-H), 2932 (C-H), 1705 (C=O), N, 18.48%. 1660 (C=C), 1415 (N=N) and 1298 cm-1 (N=O). Anal. 4-Methoxy-3-(4-nitrophenylazo) benzaldehyde, Calcd for C13H8N4O5: C, 52.00; H, 2.67; N, 18.67. 3c: IR (KBr,): 3055 (Ar C-H), 2932 (C-H), 1710 Found: C, 51.98; H, 2.66; N, 18.65%. (C=O), 1659 (C=C), 1409 (N=N), 1308 (C-O) and 5-(4-Nitrophenylazo)-3-nitro-1,5 dimethyl-3- -1 H 1302 cm (N=O). Anal. Calcd for C14H11N3O4: oxo-2-phenyl-2,3 dihydro-1 pyrazol-4-yl imino C, 58.95; H, 3.86; N, 14.74. Found: C, 58.94; H, 3.84; methyl benzene, 4f: UV-visible (λmax): 291 and 389 N, 14.72%. nm; IR (KBr): 3060 (Ar C-H), 1670 (C=N), 1657 SHARMA et al.: NEW AZO ANILS 237

(C=C), 1668 (C=O), 1409 (N=N) and 1302 cm-1 61.05; H, 4.11; N, 19.18. Found: C, 61.03; H, 4.10; N, 1 (N=O); H NMR (CDCl3): δ 2.01 (s, 3H, CH3), 2.71 19.16%. (s, 3H, CH3), 7.11-7.38 (m, 12 Ar-H) and 8.30 (s, 1H, HC=N). Anal. Calcd for C24H19N7O5: C, 61.15; H, Conclusion 4.03; N, 17.83. Found: C, 61.13; H, 4.01; N, 17.80%. The present study reports the synthesis of a new series of azo compounds 1a-f, 3a-f and from these azo Compounds 6, 7, 8 and 9 compounds azo anils 2a-f, 4a-f, 6, 7, 8 and 9 were 3-(1,5-Dimethyl–3–oxo-2-phenyl-2,3-dihydro-1H synthesized using conventional and microwave pyrazol-4-yl azo) benzaldehyde, 6: IR (KBr): 3055 irradiation method. Microwave irradiation method (Ar C-H), 2932 (C-H), 1695 (C=O ), 1649 (C=C) and gave more yields and took less time as compared to 1410 cm-1 (N=N). Anal. Calcd for C H N O : C, 18 16 4 2 conventional method. The antimicrobial activity of 67.50; H, 5.00; N, 17.50. Found: C, 67.47; H, 4.98; N, these synthesized azo anils containing pyrazole 17.48%. moiety revealed that these compounds showed minor 3-(1,5 Dimethyl–3–oxo-2-phenyl-2,3-dihydro-1H to moderate activity against bacteria and no activity pyrazol-4-yl azo) phenyl imino methyl benzene, 7: against fungus and yeast. The substitution of chloro, UV-visible (λ ): 293 and 375 nm; IR (KBr): 3055 max methoxy or nitro group on phenyl ring enhanced the (Ar C-H), 1660 (C=N), 1655 (C=C), 1673 (C=O), activity against bacteria but it was less as compared to 1400 cm-1 (N=N); 1H NMR (CDCl ): δ 2.11 (s, 3H, 3 streptomycin. CH ), 3.14 (s, 3H, CH ), 7.13-7.58 (m, 14 Ar-H) and 3 3 7.80 (s, 1H, HC=N). Anal. Calcd for C H N O: C, 24 21 5 Acknowledgement 72.91; H, 5.32; N, 17.72. Found: C, 72.90; H, 5.30; N, The authors are thankful to Panjab University 17.69%. Chandigarh for providing the facility of spectral data 3-(1,5 Dimethyl-3-oxo-2-phenyl-2,3 dihydro-1H of synthesized compounds. pyrazol-4-yl-azo)-4-nitro phenyl imino methyl benzene, 8: UV-visible (λmax): 273 and 363 nm; IR (KBr): 3062 (Ar C-H), 1676 (C=N), 1652 (C=C), References -1 1 1 Zollinger H, Color Chemistry (VCH Weinheim, Wilhey), 1670 (C=O) and 1412 cm (N=N); H NMR (CDCl3): δ 1991. 2.04 (s, 3H, CH3), 3.04 (s, 3H, CH3), 7.08-7.50 2 Hamon F, Djedaini-Pilard F, Barbot F & Len C, Tetrahdron (m, 14H) and 8.28 (s, 1H, HC=N). Anal. Calcd for Lett, 65, 2009, 10105.

C24H20N6O3: C, 65.45; H, 4.54; N, 19.09. Found: C, 3 Gordon P F, The Chemistry and Applications of Dyes 65.43; H, 4.52; N, 19.07%. (Plenum Press, New York), 1990. 4 Pathak P, Jolly V S & Sharma K P, Orient J Chem, 16, 2000, 3-(Bis-1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro- 161. 1H pyrazol-4-yl) azo imino methyl benzene, 9: UV- 5 Xu H & Zeng X, Bioorg Med Chem Lett, 20, 2010, 4193. visible (λmax) 298 and 332 nm; IR (KBr): 3065 (Ar 6 Jarrahpour A A, Motamedifar M, Pakshir K, Hadi N & Zarei C-H), 1665 (C=N), 1658 (C=C), 1675 (C=O) and M, Molecules, 9, 2004, 815.

1409 cm-1 (N=N); 1H NMR (CDCl ): δ 2.14 (s, 3H, 7 Satyanarayana V S V, Sreevani P, Sivakumar A & 3 Vijayakumar V, ARKIVOC, 17, 2008, 221. CH3), 2.76 (s, 3H, CH3), 7.13-7.42 (m, 12 Ar-H) and 8 Vats V, Upathay R K & Sharma P, Eunopena J Chem, 8, 8.25 (s, 1H, HC=N). Anal. Calcd for C26H21N7O5: C, 2011, 59.