An extensive survey by the use of high performance liquid chromatography on racemization during the coupling of benzyloxycarbonyl-L-phenylalanyl-L-valine with L-proline tert-butyl ester.
Peptides were produced in high yields and, if any, very low epimerization, by mechanochemical coupling of peptide fragments containing highly epimerization-prone and/or highly hindered amino acids at C-term. Ball milling was clearly identified as the key element enabling one to obtain such results.
通过在 C 端含有高度差向异构化和/或高度受阻氨基酸的肽片段的机械化学偶联,以高产率和(如果有的话)非常低的差向异构化产生肽。球磨被清楚地确定为获得这种结果的关键因素。
Convenient primary amidation of N-protected phenylglycine and dipeptides without racemization or epimerization
作者:Takuya Noguchi、Seunghee Jung、Nobuyuki Imai
DOI:10.1016/j.tetlet.2013.11.042
日期:2014.1
Primary amidation of N-protected phenylglycine and dipeptide proceeded easily to afford the corresponding amides in 57–95% yields with 99% ee and 81–99% de, respectively. The procedure is very easy to avoid racemization and epimerization of the products in the reactions by keeping exactly the reaction temperature at −15 °C when the activation of carboxylic acids, followed by the reaction of the mixed
2-Propanephosphonic acid anhydride (T3P)-mediated segment coupling and head-to-tail cyclization of sterically hindered peptides
作者:Jana Klose、Michael Bienert、Christoph Mollenkopf、Detlef Wehle、Chong-wu Zhang、Louis A. Carpino、Peter Henklein
DOI:10.1039/a905021c
日期:——
In the course of comparing the effectiveness of an HOAt-derived coupling reagent (HAPyU) and a phosphonic acid-based condensation agent (T3P) by cyclization of model sequences, we found that T3P was a superior reagent with regard to conversion of the linear peptide into the stereochemically intact cyclic monomer when sterically hindered amino acids are found at the cyclization site.
A novel kinetically-controlled peptide synthesis—Dramatic increase of chemical yield with retention of chiral integrity
作者:Wen-Chung Shieh、John A. Carlson、Michael E. Shore
DOI:10.1016/s0040-4039(99)01493-8
日期:1999.10
Peptide synthesis employing the highly selective reaction of isobutyl chloroformate at the carboxyl group of the N-protected amino acid, almost to the exclusion of the amino group of the C-protected amino acid, is described. This one-stage, kinetically-controlled strategy remarkably affords peptides with excellent optical purity in high chemical yields. (C) 1999 Elsevier Science Ltd. All rights reserved.