A FACILE METHOD FOR THE N-ALKYLATION OF ALPHA-AMINO ESTERS

Monoalkylation of the alpha-amino group of alpha-amino acid derivative s can be facilitated using 2- and 4-nitrophenylsulfonamide intermediat es. The nitrophenylsulfonamides of alpha-amino esters can be alkylated using an equimolar amount of carbonate base and a variety of alkyl br omides. Ready removal of the nitrophenylsulfonyl group is facilitated by SNAr reaction between the N-alkylated sulfonamide and phenylthiolat e to give the N-alkylated alpha-amino esters in good yield without rac emisation of the chiral alpha-centres. (C) 1997 Elsevier Science Ltd.