Novel 4-(morpholin-4-yl)-N'-(arylidene)benzohydrazides: synthesis, antimycobacterial activity and QSAR investigations.

A series of 4-(morpholin-4-yl)-N'-(arylidene)benzohydrazides were synthesized using appropriate synthetic route. Antimycobacterial activity of the synthesized compounds (5a-5j) was carried out and percentage reduction in relative light units (RLU) was calculated using luciferase reporter phages (LRP) assay. Percentage reduction in relative light units (RLU) for isoniazid was also calculated. The test compounds showed significant antitubercular activity against Mycobacterium tuberculosis H37Rv and clinical isolates: S, H, R, and E resistant M. tuberculosis, when tested in vitro. Quantitative structure-activity relationship (QSAR) investigation with 2D-QSAR analysis was applied to find a correlation between different experimental or calculated physicochemical parameters of the compounds studied and 3D-QSAR analysis and to indicate the exact steric and electronic requirements in the ranges at various positions around pharmacophore. In general Schiff bases exhibit antimycobacterial activity and morpholine ring is important for antimicrobial activity. So we have synthesized 10 different 4-(morpholin-4-yl)-N'-(arylidene)benzohydrazides. The structures of new compounds were characterized by TLC, FTIR, (1)H NMR, mass spectral data and elemental analysis. Amongst the compounds tested 5d and 5c were found to be the most potent, while 5i, 5e, and 5j were found to have an average activity against M. tuberculosis H37Rv and 5a, 5f, 5h, 5g, and 5b were found to have a greater activity against clinical isolates: S, H, R, and E resistant M. tuberculosis as compared to M. tuberculosis H37Rv.