B. Hemmasi, W. Stüber, E. Bayer
Jul 1, 1982
Citations
0
Influential Citations
8
Citations
Journal
Hoppe-Seyler's Zeitschrift fur physiologische Chemie
Abstract
The syntheses of 4-(Boc-aminoacyloxymethyl)-3-nitrobenzoic acids are described. These compounds are suitable reagents for coupling to polyethylene glycol or its derivatives by the dicyclohexylcarbodiimide method to obtain 4-(Boc-aminoacyloxymethyl)-3-nitrobenzoyl-polyethylene glycol support. This is demonstrated by the reaction of the 4-carboxy-2-nitrobenzyl ester of Boc-alanine with glycylpolyethylene glycol in excellent yield. This synthetic route produces a much better coupling yield and an easier purification procedure in comparison with the original method in which Boc-amino acid cesium salts are allowed to react with 4-(bromomethyl)-3-nitrobenzoyl-polyethylene glycol.