Synthesis of Casein-Related Peptides and Phosphopeptides. VIII. The Synthesis of Ser(P)-Containing Peptides by the Use of Z-Ser(PO₃R₂)-OH Derivatives

Abstract

.The synthesis of five Z-Ser(PO₃R₂)-OH (R = phenyl, ethyl, methyl, benzyl, t-butyl) derivatives is described by a simple three-step synthetic procedure which features the use of either (A) diphenyl or dialkyl phosphorochloridate /pyridine or (B) dialkyl N,N-diethylphosphoramidite/1H-tetrazole-m-chloroperoxybenzoic acid for the phosphorylation of the serine hydroxy group. The benzyl phosphate derivative, Z-Ser(PO₃Bzl₂)-OH, was used in the benzyloxycarbonyl mode of peptide synthesis for the preparation of Z-Ser(PO₃Bzl₂)-Leu-OBzl and Z-Ser(PO₃Bzl₂)-Ser(PO₃Bzl₂)- OBzl which were deprotected by palladium- catalysed hydrogenolysis to give Ser(P)-Leu and Ser(P)-Ser(P) in high yields and high purity.