Room-Temperature Debenzylation of N-Benzylcarboxamides by N-Bromosuccinimide

Abstract

A simple and highly efficient method has been developed with which to cleave the N-benzyl group on N-mono- or di­substituted carboxamides using N-bromosuccinimide (NBS) at room temperature. All the 31 substrates examined showed moderate to excellent deprotection yields. Our study also indicated that the debenzylation may involve an oxygen/light initiated free radical mechanism.

Key words

NBS - debenzylation - carboxamides - free radical

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16

NMA initiated bromination of toluene. To a solution of toluene (2.0 mmol) in CHCl₃ (20 mL), NMA (0.2 mmol) and NBS (5.0 mmol) were added. The resulting mixture was stirred at r.t. for 24 h. TLC clearly indicated the formation of benzyl bromide and the reaction was further confirmed by GC/MS.