Synthesis and Antimicrobial Evaluation of Azetidinone Derivatives of Pyridine Containing Hydrazides

Isoniazid (1a) undergoes facile condensation with indole-3-carboxaldehyde in methanolic media and glacial acetic acid as a catalyst to afford the corresponding N-((1H-indol-3-yl)methylene) nicotinohydrazide (2a). Cyclocondensation of compounds (2a) with chloro acetyl chloride, triethyl amine and 1,4-dioxane yields N-(3-chloro-2-(1H-indol-3-yl)-4-oxoazetidin-1-yl)nicotinohydrazide (3a). Further the NH proton of indole in compounds (3a) is replaced with different benzo[b]thiophenes to yield the final compound N-(3-chloro-2-(1-(3-chlorobenzo[b]thiophene-2-carbonyl)-1H-indol-3-yl)-4-oxoazetidin-1-yl) nicotinohydrazide (4a-d). In an alternative reaction Nicotinic-hydrazide (1b) is used in place of Isoniazid and reacted with indole-3-carboxaldehyde to produce N-((1H-indol-3-yl)methylene) isonicotinohydrazide (2b). Compound (2b) on reaction with chloroacetylchloride, triethylamine and 1,4-dioxane synthesize N-(3-chloro-2-(1H-indol-3-yl)-4-oxoazetidin-1-yl)isonicotinohydrazide (3b). In the final stage of the reaction scheme the NH proton of compound (3b) is replaced with different benzo[b]thiophenes to yield the final compounds N-(3-chloro-2-(1-(3-chloro benzo[b]thiophene-2-carbonyl)-1H-indol-3-yl)-4-oxoazetidin-1-yl)isonicotinohydrazide (4e-h). The structures of these compounds were established on the basis of analytical and spectral data. The newly synthesized compounds were evaluated for their antibacterial and antifungal activities.