Development of Practical Synthetic Method for Phosphopeptides using Two-step Deprotecting Procedures

点击翻译按钮获取中文摘要

A protocol has been developed for the synthesis of peptides containing O-phosphorylated tyrosines, serines, and/or threonines. The procedure involves incorporation of dimethyl-protected phosphorylated amino acid derivatives into peptides using Boc chemistry and subsequent removal of Me groups using a two-step deprotection method consisting of high acidic and low acidic treatments. Optimized deprotection conditions for the protected resins were established, which consist of a combination of the first-step reagent (1 M TMSOTf-thioanisole in TFA,m-cresol, EDT) and the second-step reagent (first-step reagent + DMS-TMSOTf). Furthermore, the second-step reagent can be changed to the more effective reagent system (TMSOTf-DMS-m-cresol-EDT). Theses synthetic method afforded phosphoamino acid-containing peptide in high yield without significant accompanying side reactions. For a phosphoprotein synthesis, we developed SN1-deprotecting procedure (TFMSA-TFA-m-cresol). Treatment of protcted phosphopeptide thioester resins with this system afforded protected phosphopeptide thioesters, in which side chains of Lys and phosphoamino were protected with CLZ or Me grpoups, respectively. Synthetic studies on phosphoprotein utilizing protected phosphopeptide thioesters are in progress.