Smita D. Rajani

Pharmacological evaluation and characterizations of newly synthesized 1,2,4-triazoles

The triazole analogs were obtained via. multistep synthesis sequence beginning with ethyl nicotinoate 3 which on treatment with hydrazine hydrate yields nicotinoyl hydrazide 4. Intermolecular cyclisation of 4 with 4-methylbenzoic acid in presence of phosphorous oxy chloride affords 2-(3-pyridyl)-5-(4-methylphenyl)-1,3,4-oxadiazole 5. Condensation of 5 with various substituted 2-hydrazino benzothiazole 2a-j results in 3-(3-pyridyl)-5-(4-methylphenyl)-4-(N-substituted-1,3-benzothiazol-2-amino)-4H-1,2,4-triazole 6a-j analogs. All the compounds have been characterized by elemental analysis, IR, (1)H NMR, (13)C NMR and mass spectral data. In vitro antitubercular activity was carried out against Mycobacterium tuberculosis H(37)Rv strain using Lowenstein-Jensen medium and antimicrobial activity against various bacteria and fungi using broth microdilution method. Compounds 2e, 6a, 6b, 6c, 6d, 6g, 6h and 6i emerged as promising antimicrobials. It was also observed that the promising antimicrobials have proved to be better antituberculars. Compound 6j showed better antitubercular activity compared to rifampicin.

Antimycobacterial and antimicrobial study of new 1,2,4-triazoles with benzothiazoles

In this study, we report the antimycobacterial and antimicrobial evaluation of newly synthesized 3‐(3‐pyridyl)‐5‐(4‐methoxyphenyl)‐4‐(N‐substituted‐1,3‐benzothiazol‐2‐amino)‐4H‐1,2,4‐triazole 6a–j in good yields. All the synthesized compounds have been established by elemental analysis, IR, 1H NMR, 13C‐NMR and Mass spectral data. In‐vitro antimycobacterial activity was carried out against (Mycobacterium tuberculosis) H37Rv strain using Lowenstein‐Jensen medium and antimicrobial activity against two Gram positive bacteria (Staphylococcus aureus, Streptococcus pyogenes), two Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and three fungal species (Candida albicans, Aspergillus niger, Aspergillus clavatus) using the broth microdilution method. Compounds 2e, 6a, 6g, 6h, and 6j exhibited promising antimicrobial activity whereas compound 6j showed very good antimycobacterial activity.

A one pot, three component synthesis of coumarin hybrid thiosemicarbazone derivatives and their antimicrobial evolution

Abstract A convenient, one-pot, multi-component protocol for the preparation of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinecarbothioamide derivatives has been achieved. Here, firstly we have reported the synthesis of 3-acetyl-2H-chromen-2-one using starch sulfuric acid and cellulose sulfuric acid as biodegradable catalysts. Subsequently, we also carried out the reaction of isothiocynates, hydrazine hydrate and 3-acetyl-2H-chromen-2-one in the presence of catalytic amount of glacial acetic acid in refluxing ethanol to afford corresponding 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinecarbothioamide derivatives in high to excellent yields. All synthesized compounds were screened for antimicrobial activity. All compounds were found to show good to excellent activity against Escherichia coli MTCC 443.

In vitro antimicrobial and antitubercular studies of novel 6-substituted (pyrrolidin-1-yl)-2(1H)-pyridinones

A series of 6-amino-substituted pyridine-2-(1H)-ones have been prepared by coupling of substituted 6-(pyrrolidin-1-yl)-2(1H)-pyridinones with aryl diazonium chlorides. The overall sequence provides a simple and efficient route to prepare 6-amino-substituted pyridine-2-(1H)-ones in the form of two isomers, which were separated using column chromatography. The structure of all the compounds has been assigned unambiguously on the basis of elemental analysis, IR and NMR spectral data and has been evaluated for antibacterial and antifungal activities. The active compounds were evaluated for antitubercular activity and compared with standard drug rifampicin.

Benzene sulfonamide pyrazole thio-oxadiazole hybrid as potential antimicrobial and antitubercular agents

To fulfil the development goals towards the synthesis of innovative, potent and highly effective antimicrobial and antimycobacterial agents, a set of benzene sulfonamide pyrazole thio-oxadiazole derivatives (6a–6l) have been synthesized by the reaction of 4-[5-(3-fluoro-4-methoxyphenyl)-3-(5-mercapto-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl]benzenesulfonamide with alkyl/aryl halides, identified by IR, NMR (1H, 13C, 19F) and MS data. Composed compounds were examined for their antimicrobial and antitubercular activity. Antibacterial activity of compounds 6c, 6d, 6j and 6l was found promising against E. coli, P. Aeruginosa, S. Aureus and S. Pyogenes as compared to standard ampicillin. Compounds 6d, 6e, 6g, 6h and 6i were found active against tubercular strain H37Rv. Molecular docking studies against mycobacterium tuberculosis β-ketoacyl-acyl carrier protein synthase A (Kas-A) was carried out which suggests a possible mode of inhibition for this target protein and the potential of synthesized compounds as antitubercular agents.