Synthesis and antimicrobial screening of N-[coumarin-6-ylamino]thiazolidinone and spiro indolo-thiazolidinone derivatives

Abstract

Condensation of N-[coumarin-6-yl]hydrazonoarylmethanes <b style="">3a-h</b> obtained from the condensation of the coumarin-6-ylhydrazine hydrochloride <b>2a-d</b> and aromatic aldehydes, on treatment with mercaptoacetic acid in dry 1,4-dioxane in the presence of catalytic amount of anhydrous zinc chloride yields N-[coumarin-6-ylamino]-2-arylthiazolidin-4(<i>H</i>)-ones <b style="">4a-h</b>. While, coumarin-6-ylhydrazine hydrochloride <b style="">2a-d</b> on condensation with isatin <i>in situ</i> yields corresponding 1,2-dihydro-3-[coumarin-6-ylhydrazono]indol-2-ones <b style="">5a-d</b>. Compound <b>5a-d</b> on treatment with mercaptoacetic acid in dry 1,4-dioxane in the presence of catalytic amount of anhydrous zinc chloride affords N-[coumarin-6-ylamino]spiro-[3<i style="">H</i>-indole-(1<i>H</i>,2<i>H</i>)-3,2-(4<i>H</i>)-thiazolidine]-2,4-diones <b style="">6a-d</b>. The structures of the compounds <b>3</b>, <b>4</b>, and <b>6</b> have been confirmed on the basis of their spectral and analytical data. The above compounds are screened for their antimicrobial activities and have been found to exhibit significant antibacterial and antifungal activities.