Cross-Coupling Reactions of Chloropyrazines with 1-Substituted Indoles

Abstract

Palladium-catalyzed coupling reactions of 2-chloro-3,6-dialkylpyrazines with 1-tosylindole gave l-tosyI-3-(3,6-dialkylpyrazin-2-yl)indoles as the main product in each case. The subsequent hydrolysis of the products yielded the corresponding 3-(3,6-dialkylpyrazin-2-yl)indoles under alkaline conditions. Coupling reactions of 2-chloro-3,6-dialkylpyrazines with 1-methyl- or 1-benzylindole occurred at the 2-position of the indoles, but 2-chloro-3,5-diphenylpyrazine (le) failed to react with 1-methylindole. © 1989, The Pharmaceutical Society of Japan. All rights reserved.