Oxidative Cleavage Reaction of 3-Substituted Indoles Catalyzed by CuCl–Pyridine Complex under Oxygen

Abstract

Abstract Oxidative cleavage of 3-methylindole using a catalytic amount of copper(II) salts with added pyridine under an oxygen atmosphere was studied. Smooth cleavage of 3-methylindole took place to give 2-formamidoacetophenone in 73–80% yield, whereas exclusive formation of a hydrate compound derived from 3,3′-dimethyl-3,3′-bi-3H-indole resulted under anaerobic conditions. Clean oxidative cleavage of N-acetyltryptamine, methyl 3-indolylacetate, and methyl 2-acetamido-3-(3-indolyl)propionate was also achieved, constituting a mimic of tryptophan-2,3-dioxygenase.