2007 年 55 巻 1 号 p. 124-127
The preparation of amide derivatives (4) by N-acylation of unprotected α-amino acids is easily achieved via readily available benzotriazolyl carboxylates (2a—d) or succinimidyl carboxylates (2e—f). These intermediates (2) are prepared from reaction of carboxylic acids (1) with 1-hydroxybenzotriazole (HO-Bt) or N-hydroxysuccinimide (HO-Su) in the presence of equimolar amounts of 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide hydrochloride (WSCI). The overall yields of the target compounds (4) were excellent, and this two-stage procedure could be applicable as an alternative procedure for one-pot reaction.