Synthesis of novel 3- and 5-substituted indole-2-carboxamides

✍ Scribed by Larry D. Bratton; Bruce D. Roth; Bharat K. Trivedi; Paul C. Unangst

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2000
• Tongue: English
• Weight: 434 KB
• Volume: 37
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570370513

✦ Synopsis

Abstract

The preparation of several novel 3,5‐substituted‐indole‐2‐carboxamides is described. A 5‐nitro‐indole‐2‐carboxylate was elaborated to the 3‐benzhydryl ester, N‐substituted ester, and carboxylic acid intermedi ates, followed by conversion to the amide and then reduction of the 5‐nitro group to the amine. Indole‐2‐carboxamides with 3‐benzyl and 3‐phenyl substituents were prepared in four steps from either a 3‐bromo indole ester using the Suzuki reaction or from a 3‐keto substituted indole ester. N‐Alkylation of ethyl indole‐2‐carboxylate, followed by amidation and catalytic addition of 9‐hydroxyxanthene gave a 3‐xanthyl‐indole‐2‐carboxamide analog and a spiropyrrolo indole as a side product.