Asparagine peptide was selectively cleaved by the Hofmann rearrangement followed by an alkaline treatment at the peptide linkage in which an amino group of the asparagine residue participated. Upon reaction of N-benzyloxycarbonyl-l-alanyl-l-asparagine with one equivalent of bromine and three equivalents of aqueous sodium hydroxide solution at 60°C, 1-(N-benzyloxycarbonyl-l-alanyl)-2-oxoimidazolidine-5-carboxylic acid was obtained in quantitative yield. When this was treated with an aqueous methanolic sodium hydroxide solution at room temperature, a cleavage reaction occurred to give N-benzyloxycarbonyl-l-alanine and 2-oxo-imidazolidine-5-carboxylic acid. Under the same condition of the rearrangement, N-benzyl-oxycarbonyl-l-asparaginyl-l-phenylalanine was converted to 1-benzyloxycarbonyl-2-oxoimidazo-lidine-5-carbonylphenylalanine. Since glutamine peptide could not give the corresponding ring compound, this cleavage reaction was found to be specific to asparagine peptide.
Quantitative description of epimerization pathways using the carbodiimide method in the synthesis of peptides
作者:Carola Griehl、Alfred Kolbe、Susanne Merkel
DOI:10.1039/p29960002525
日期:——
mechanism of epimerization in carbodiimidesynthesis has been investigated by varying the side chain of the activated acids. A series of peptides N-benzyloxycarbonyl-Ala-Xaa-OH with 20 different residues Xaa were coupled with valine methyl ester in dichloromethane and dimethylformamide. The kinetic data and the extent of epimerization were determined for the peptide synthesis and the aminolysis of isolated
Process for the production of glutamine derivatives
申请人:Ajinomoto Co., Inc.
公开号:US05032675A1
公开(公告)日:1991-07-16
Improved methods for synthesizing glutamine-containing peptides, involving an active ester method between a protected, C-terminal activated amino acid or a protected, C-terminal activated peptide, and unprotected glutamine in the presence of a weak base, are disclosed.