Esterification of Unprotected α-Amino Acids in Ionic Liquids as the Reaction Media

Ionic liquid 1,3-dimethylimidazolium methanesulfonate was used to prepare α-amino acids benzylic esters from unprotected amino acids and benzyl chloride. Esterification of several amino acids was achieved with satisfactory yields: by-products can be removed by a simple work-up procedure to afford the pure product. The described method is simple, mild, rapid and save.