Trimethoxyphenylthio as a Highly Labile Replacement for tert-Butylthio Cysteine Protection in Fmoc Solid Phase Synthesis
摘要:
Trimethoxyphenylthio (S-Tmp) is described as a novel cysteine protecting group in Fmoc solid phase peptide synthesis replacing the difficult to remove tert-butylthio. S-Tmp and dimethoxyphenylthio (S-Dmp) were successfully used for cysteine protection in a variety of peptides. Moreover, both groups can be removed in 5 min with mild reducing agents. S-Tmp is recommended for cysteine protection, as it yields crude peptides of high purity.
Tetrahydropyranyl (Thp), which exploits the concept of being an S,O-acetal nonaromatic protectinggroup for cysteine, has been shown to be superior to Trt, Dpm, Acm, and StBu in solid-phase peptide synthesis using the Fmoc/tBu strategy. Thus, Cys racemization and C-terminal 3-(1-piperidinyl)alanine formation were minimized when the Cys was protected with Thp. This nonaromatic protectinggroup also
四氢吡喃基(THP),其利用的是一个概念小号,ö -acetal非芳香族保护基为半胱氨酸,已被证明优于TRT,DPM,ACM,和S吨在使用Fmoc固相肽合成BU / t Bu策略。因此,当Cys被Thp保护时,Cys外消旋作用和C末端3-(1-哌啶基)丙氨酸的形成被最小化。该非芳族保护基团还改善了含Cys的被保护肽的溶解性。