Synthesis, spectral characterization and bioactivity studies of some S-substituted derivatives of 5-(4-chlorophenyl)-1,3,4-Oxadiazol-2-thiol

Abstract

A new series of 5-(4-Chlorophenyl)-1,3,4-Oxadiazol-2-thiol derivatives was prepared from 4-chlorobenzoic acid (1) by converting it successively into corresponding ester (2), carbohydrazide (3) and 5-(4-Chlorophenyl)-1,3,4-Oxadiazol-2-thiol (4). Finally the target compounds, 6a-l, were synthesized by stirring 4 with different electrophiles, 5a-l, in DMF using NaH as weak base and activator. The proposed structures of newly synthesized compounds were confirmed by spectroscopic techniques such as ¹H-NMR, ¹³C-NMR, HR-MS and EI-MS. All synthesized compounds were evaluated for their anti-bacterial, antifungal, cytotoxicity and enzyme inhibition activities. The compounds, 6e and 6g exhibited significant inhibition activity against acetyl cholinesterase enzyme (AChE) and 6j moderate activity against butyryl cholinesterase enzyme (BChE). The molecule, 4 exhibited good MIC (minimum inhibitory concentration) value against all the bacterial and fungal strains taken into account.