Occurrence and Minimization of Cysteine Racemization during Stepwise Solid-Phase Peptide Synthesis<sup>1</sup><sup>,</sup><sup>2</sup>
作者:Yongxin Han、Fernando Albericio、George Barany
DOI:10.1021/jo9622744
日期:1997.6.1
suitable additives such as 1-hydroxybenzotriazole (HOBt) or 7-aza-1-hydroxybenzotriazole (HOAt) plus a tertiary amine base such as N,N-diisopropylethylamine (DIEA) or N-methylmorpholine (NMM). Under such conditions, the levels of racemization in the model peptide, expressed as the ratio of D:L peptide formed, were in the entirely unacceptable range of 5-33%. However, these levels were in general reduced
与肽合成领域的常规智慧相反,N,S保护的半胱氨酸衍生物可以通过广泛使用的试剂和逐步掺入的方案进行大量消旋。已根据偶联条件和β-硫醇保护基(即S-乙酰氨基甲基(Acm),S-三苯甲基(三苯甲基或Trt),S-2,4,6-三甲氧基苄基)进行了系统研究。 (Tmob)和S-9H-黄嘌呤9-基(Xan),利用方便且定量的模型系统测定,包括从H-Gly HPLC分离H-Gly-L-Cys-Phe-NH(2) -D-Cys-Phe-NH(2)。例如,由,盐和铵盐,例如六氟磷酸(苯并三唑基氧基)三(二甲氨基)phosph(BOP)介导的偶联的标准方案,N-[((1H-苯并三唑-1-基)(二甲基氨基)亚甲基] -N-甲基甲基六氟磷酸铵N-氧化物(HBTU),N-[[((二甲基氨基)-1H-1,2,3-三唑[4,5] -b]吡啶基-1-基]亚甲基] -N-甲基甲基六氟磷酸铵N-氧化物(HATU)和(7-氮杂