Synthesis and Antibacterial Activity of (E)-N'-[4-{2-(4-Fluorophenylthio)ethoxy}-3-cyano-5-methoxybenzylidene]-substituted benzohydrazide Derivatives

摘要

Commercially available vanillin was used as the starting material for the preparation of some new (E)-N'-[4-{2-(4-fluorophenylthio)-ethoxy)-3-cyano-5-methoxybenzylidene]-4-substituted benzohydrazide derivatives (8.1 to 8.10) in quantitative yields. The structural confirmations of all the newly synthesized hydrazone derivatives were established on the basis of ~1H NMR, mass and IR data. Hydrazides such as (E)-N'-[4-{2-(4-fluorophenylthio)ethoxy}-3-cyano-5-methoxybenzylidene]-2,5-dichlorobenzohydrazide (8.6), (E)-N'-[4-{2-(4-fluorophenylthio)ethoxy}-3-cyano-5-methoxybenzylidene]-2,5-difluorobenzohydrazide (8.9) showed duplication of NMR signals, this was attributed to the presence of anti and syn periplanar conformers. Antibacterial study against Staphylococcus aureus. Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa with reference to the standard drug (streptomycin) revealed that compounds bearing R = 4-OH (8.2), 3,4,5-OMe (8.3) and 4-SO2Me (8.4) substituents has shown the good antibacterial sensitivity.