Synthetic Studies on Indoles and Related Compounds. XXVI. The Debenzylation of Protected Indole Nitrogen with Aluminum Chloride. (2).

Abstract

A new debenzylation method using aluminum chloride in benzene or anisole, which had been developed by us for N-benzyl-2-acyl- and -2-ethoxycarbonylindoles, was applied to benzyl derivatives of other types of indoles and related compounds. Among them, N-benzyl derivatives of fully aromatized indoles, carbazoles and β-carbolines, and some benzamides were debenzylated successfully, whereas those of oxindoles and heterocyclic amides were not. As to the effect of a p-substituent on the benzyl group, it was found that an electron-donating substituent accelerates deprotection, whereas an electron-attracting substituent delays or prevents deprotection.