Acid mediated deprotection of N-isopropyl tertiary amides

Tertiary amides containing an N-isopropyl group were selectively deprotected by heating in methanesulfonic acid. The N-isopropyl group was removed selectively in the presence of other groups on the amide nitrogen such as methyl, primary alkyl, or aryl. The putative isopropyl cation was trapped by Friedel-Crafts alkylation of anisole when the latter was included as a co-solvent. (C) 2015 Elsevier Ltd. All rights reserved.