Novel isoniazid cyclocondensed 1,2,3,4-tetrahydropyrimidine derivatives for treating infectious disease: a synthesis and in vitro biological evaluation

Objective: To synthesize new congeners by incorporating isoniazid with 1,2,3,4-tetrahydropyrimidinones moieties in a single molecular frame work and to evaluate their antimicrobial and antimycobacterial activity. Methods: A new series of some novel isoniazid cyclocondensed 1,2,3,4-tetrahydropyrimidines was prepared by N′-acetoacetylisonicotinohydrazide with urea/thiourea and appropriate aldehyde in the presence of catalytic amount of laboratory made benzenesulphonic acid. Confirmation of the chemical structure of the synthesized compounds (4a-n) was substantiated by melting point, TLC, different spectral data IR, 1H-NMR, and Mass spectra were done. The synthesized compounds were evaluated for in vitro antimicrobial and antimycobacterial activity against Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), Mycobacterium tuberculosis (M. tuberculosis) CIP and H37Rv strain. Results: The titled compounds exhibited weak, moderate, or high antimicrobial and antimycobacterial activity. Compounds 4l, 4m, and 4n, exhibited potential antimicrobial and antimycobacterial action, when compare with the current therapeutic agent of Norfloxacin and Rifampicin. Conclusions: Compound 4l, 4m, and 4n is arguably the most potent, our present study makes it an interesting compound when compared to the current therapeutic agents and are considered the candidates to investigate further for the same