Solution Phase Synthesis of Glu-Abu(P)-Leu by Using Z-Abu(PO₃Et₂)-OH

Abstract

This paper describes the synthesis of the 2-amino-4-(phosphono)butanoyl-containing peptide H-Glu-Abu(P)-Leu-OH.CF₃CO₂H by the use of Z-Abu(PO₃Et₂)-OH for the solution phase synthesis of Boc-Glu(Obu^t)-Abu(PO₃Et₂)-Leu-Obu^t (mixed-anhydride method) followed by acidolytic cleavage of the t-butyl groups, and final removal of the ethyl groups from Glu- Abu(PO₃Et₂)-Leu by treatment with 10% bromotrimethylsilane in acetonitrile. Although silylitic cleavage of the peptide was facile, the slow dissolution of the peptide in the reaction solvent suggests that deprotection of the Abu(PO₃.Et₂) residue has not yet been optimized.