Synthesis of Casein-Related Peptides and Phosphopeptides. V. The Efficient Global 'Phosphite-Triester' Phosphorylation of Protected Serine Derivatives and Peptides by Using Dibenzyl or Di-t-butyl N,N-Diethylphosphoramidite

Abstract

Both dibenzyl N,N- diethylphosphoramidite and di -t-butyl N,N- diethylphosphoramidite are shown to be suitable reagents for the efficient 1H-tetrazole-catalysed 'phosphite-triester' phosphorylation of the protected serine derivative Boc-Ser-OCH2C6H4NO2-p. Both these reagents were also used for the phosphorylation of the protected serine derivative Boc-Glu ( OBut )-Ser- Leu-OBut, and subsequent hydrogenolytic treatment of Boc-Glu ( OBut )-Ser(PO3Bzl2)- Leu-OBut or acidolytic treatment of Boc-Glu ( OBut )-Ser(PO3But2)- Leu-OBut gave the O- phosphoseryl tripeptide Glu -Ser(PO3H2)- Leu in near-quantitive yield.