A novel direct conversion of primary amides to their corresponding methyl esters

A novel method was used to directly convert aliphatic and aromatic primary amides into their corresponding methyl esters in high yields (up to 99%) under mild reaction conditions. Possible mechanisms were studied at the B3LYP/6-31++G(d,p) level of theory. Formation of the ester proceeded through a rearrangement of the -OMe and -NH2 groups in the RC(O)NHS(O)OMe intermediate in a H+-catalyzed six-membered ring transition state structure. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).