Facile synthesis of some new azetidinones and acetyl oxadiazoles bearing benzo[b]thiophene nucleus as a potent biological active agent

Abstract

2-Hydrazinocarbonyl-3-chloro-5-phenoxybenzo[b]thiophene <b>1</b> has been prepared by the condensation of 3-chloro-5-phenoxybenzo[b]thiophenoyl chloride with hydrazine hydrate. Compound <b>1</b> on condensation with aromatic aldehyde furnishes 2-substituted benzalhydrazinocarbonyl-3-chloro-5-phenoxybenzo[b]thiophenes <b>2a-l</b>, which on further cyclo­condensation with chloroacetyl chloride in the presence of triethyl amine afford 4-aryl-3-chloro-1-(3'-chloro-5'-phenoxy-2'-benzo[b]thiophenoylamino)-2-azetidinones <b>3a-l</b>. Compounds <b>2a-l</b> on reaction with acetic anhydride yield 2-(3'-chloro-5'-phenoxybenzo[b]thiophene-2'-yl)-4-acetyl-5-aryl-4,5-dihydro-1,3,4-oxadiazoles <b>4a-l</b>. The structures of the compounds <b>2a-l</b>, <b>3a-l</b> and <b>4a-l</b> have been confirmed by elemental analysis and IR, ¹H NMR and mass spectral data. All the compounds have been screened for their antitubercular activity towards <i>Mycobacterium tuberculosis </i>H₃₇Rv and antimicrobial activity against different microbes.