1,3-Dipolar cycloaddition reactions: Synthesis and antimicrobial activity of novel 1-triazolylethylindole and 1-triazolylethylbenz[g]indole derivatives

Abstract

Indole azide <b style="">4</b> and benz[g]indole azide <b style="">12</b> are reacted separately with dimethyl acetylenedicarboxylate to secure the desired 1-[4,5-dimethoxycarbonyl-1,2,3-triazol-1-yl]ethyl-3-ethoxycarbonyl-5-methoxy-2-methylindole <b style="">5</b> and 1-[4,5-di­methoxy­carbonyl-1,2,3-triazol-1-yl]ethyl-3-ethoxycarbonyl-5-methoxy-2-methylbenz[g]indole <b style="">13,</b> respectively. The reac­tion of indole azide <b style="">4</b> and benz[g]indole azide <b style="">12</b> with ethyl propiolate has been found to be regiospecific and produce only the 1-[4-ethoxycarbonyl-1,2,3-triazol-1-yl]ethyl-3-ethoxycarbonyl-5-methoxy-2-methylindole <b style="">6</b> and 1-[4-ethoxycarbonyl-1,2,3-triazol-1-yl]ethyl-3-ethoxycarbonyl-5-methoxy-2-methylbenz[g]indole <b style="">14,</b> respectively. Indole azide <b style="">4</b> is also reacted with ethyl phenylpropolate to secure two isomeric products 1-[4-ethoxycarbonyl-5-phenyl-1,2,3-triazol-1-yl]ethyl-3-ethoxycarbonyl-5-methoxy-2-methylindole <b style="">8</b> and 1-[4-phenyl-5-ethoxycarbonyl-1,2,3-triazol-1-yl]ethyl-3-ethoxycarbonyl-5-methoxy-2-methylindole <b style="">9</b>. All these newly synthesised compounds are screened for their antimicrobial activities.