Abstract

SYNTHESIS AND ANTIBACTERIAL ACTVITY OF NEW INDOLYL CHALCONE IMINE DERIVATIVES OF 5-AMINO-1, 3, 4- THIADIAZOLE-2-THIOL

Bahar Ahmed, Mohsin Hasan*

Abstract

This research article is aimed to synthesize and evaluate antimicrobial activity of a series of newly synthesized (5Z)-5-(E)-3-(1H-indoly-3- yl)-1-phenylallylideneamino)-2, 5-dihydro-1, 3, 4-thiadiazole-2-thiol 1(a-h). First of all N-substituted indole-3-carboxaldehyde derivatives are prepared from a mixture of Indole-3-carboxaldehyde (10 mmol), the appropriate alkylating reagent, anhydrous K2CO3 and DMF was stirred vigorously and refluxed for 6 h. After completion of reaction as monitored by TLC, the reaction mixture was cooled and poured into water. The precipitated solid was filtered off, washed with water dried and recrystalised from methanol. These derivatives which undergo Claisen-Schmidt condensation with phenyl acetone and p- Chlorophenyl acetone yielded indolylchalcone derivatives 2(a-h). These indolylchalcone derivatives condensed with 5-amino-1, 3, 4- Thiadiazole-2-thiol in alcoholic KOH for 3 h followed by additionelimination reaction to afford final compound 4(a-h).The structure of newly synthesized compounds was characterized by 1H NMR, 13C NMR, IR, and elemental analysis. The antimicrobial activity of the novel compounds 4(a-h) was screened by agar disc diffusion method. Some of the derivatives exhibited promising antibacterial activity and therefore could be considered as new lead compounds for further lead optimization studies.

Keywords: Antibacterial activity, Claisen-Schmidt condensation, DMF, Indole-3- carboxaldehyde, Indloylchalcones; 1, 3, 4- thiadiazole.