Design, synthesis, computational calculation and biological evaluation of some novel 2-thiazolyl hydrazones

In the present study a novel series of 1-(1-(4-isobutylphenyl)ethylidene)-2-(4-phenylthiazol-2-yl)hydrazine 2a and its derivatives 2b-2f have been synthesized by the cyclization of 1-(1-(4-isobutylphenyl)ethylidene)thiosemicarbazide with 2-bromoacetophenone/ 4-substituted 2-bromoacetophenones. The structures of the synthesized thiazolyl hydrazones 2a-2f were characterized by FT-IR, H-1, C-13 NMR, 2D NMR and mass spectral techniques. The molecular geometries were also investigated theoretically using B3LYP functional with 6-311G(d,p) basis set. To explain the molecular properties energy gap (Eg), electronegativity (chi), hardness (g), electrophilicity (omega) and softness (S) were computed, natural bonding orbital (NBO) analysis and molecular electrostatic potential (MEP) were also performed at the same level of theory. All the synthesized thiazolyl hydrazones 2a-2f were screened for their in vitro antimicrobial activity against selected bacterial and fungal strains. The results showed that the heterocyclic thiazolyl hydrazone derivatives exhibit a promising selective inhibitory activity against various bacterial and fungal strains. (C) 2014 Elsevier B.V. All rights reserved.