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

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2015-01, Vol.135, p.984-993
• Main Authors: Anbazhagan, R., Sankaran, K.R.
• Format: Article
• Language: English
• Subjects: Antimicrobial activity; DFT calculation; NBO analysis; NMR spectral; Thiazolyl hydrazones
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2014.06.160

[Display omitted] •A novel series of thiazolyl hydrazones 2a–2f synthesized and characterized.•Molecular geometries of 2a–2f are optimized and structural parameters were derived.•Frontier molecular orbital energies, MEP and NBO were analyzed.•Compounds 2c, 2e and 2f show excellent antimicrobial activity than reference drugs. 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, 1H, 13C 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 (χ), hardness (g), electrophilicity (ω) 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.