Synthesis and evaluation of antimycobacterial activity and molecular docking of 4-(benzyloxy)benzaldehyde-3,5-dinitrobenzohydrazone: A combined experimental and theoretical approaches

Abstract

The 4–(Benzyloxy) benzaldehyde–3, 5–dinitrobenzohydrazone (3) has been synthesized spectroscopically, characterized and its antitubercularactivity has been evaluated. All the quantum chemical calculations have been carried out using DFT level of theory, B3LYP functional and 6-311++G(d,p) basis set. The presence of chemical shift of azomethine proton singlet at 8.246 ppm and absence of singlet at 3.1 ppm in experimental 1H NMR spectrum indicated that the molecule exits in hydrazide-hydrazone form. The N–H stretching band in the FT-IR spectrum of (3) show Davidov coupling between the neighboring units and observed in the region 3471–3226 cm–1. NBO analysis confirms the various intramolecular charge transfer from donor to acceptor and stabilize the molecule upto∼24.65 kcal/mol due to π→π* and upto∼16.60 kcal/mol due to n→π* interaction. The maximum values of the electrophilic reactivity descriptors at C14 indicate that this site is more prone to nucleophilic attack. The local reactivity descriptors for (3) favor the formation of oxadiazoline, thiadiazoline, thiazolidinones, azetidinonesetc by attack of nucleophilic part of the dipolar reagent on C14 site of C14=N15 bond. The calculated β0 (14.3915 × 10–31 esu) value indicates it's suitability for NLO application. The compound (3) was evaluated for their antitubercular potential against Mycobacterium tuberculosis H37Rv using microplate alamar blue assay (MABA). Docking study of (3) showed binding conformations and affinities with the target protein through hydrogen bonding.