Synthesis and antibacterial screening of S-substituted derivatives of 5-(3,4-methylenedioxyphenyl)-1,3,4-oxadiazol-2-thiol.

The most emerging class among the heterocyclic compounds is 1,3,4-oxadiazoles for their diverse biological activities. In the present research work, piperonylic acid (1) was converted consecutively into corresponding ester (2), hydrazide (3) and 1,3,4-oxadiazole (4) through intermolecular cyclization. The synthesized compound 4 was subjected further to S-alkylation/aralkylation, using alkyl/aralkyl halides (5a-m) and S-substituted-1,3,4-oxadiazole derivatives were synthesized (6a-m). The structure elucidation of the synthesized molecules was processed through (1)H-NMR, IR and mass spectral data. The antibacterial activity showed these molecules moderately good inhibitors of gram-negative and gram-positive bacteria.