A versatile and selective chemo-enzymatic synthesis of β-protected aspartic and γ-protected glutamic acid derivatives
作者:Timo Nuijens、John A.W. Kruijtzer、Claudia Cusan、Dirk T.S. Rijkers、Rob M.J. Liskamp、Peter J.L.M. Quaedflieg
DOI:10.1016/j.tetlet.2009.03.130
日期:2009.6
Two versatile, high yielding, and efficient chemo-enzymatic methods for the synthesis of beta-protected Asp and gamma-protected Glu derivatives using Alcalase are described. The first method is based on the alpha-selective enzymatic hydrolysis of symmetrical aspartyl and glutamyl diesters. The second method involving mixed diesters comprises a three-step protocol using (i) alpha-selective enzymatic methyl-esterification, (ii) chemical beta-esterification, and finally (iii) alpha-selective enzymatic methyl ester hydrolysis. The yields of the purified beta- and gamma-esters range from 77% to 91%. (C) 2009 Elsevier Ltd. All rights reserved.