Synthetic studies on threonines. The preparation of protected derivatives of d-allo- and l-allo-threonine for peptide synthesis
作者:Paul Lloyd-Williams、Agustí Sánchez、Natàlia Carulla、Teresa Ochoa、Ernest Giralt
DOI:10.1016/s0040-4020(97)00059-8
日期:1997.3
threonine derivatives, having tert-butyl or benzyl-based side-chain protection, form isolable 5(4H)-oxazolones on treatment with N-ethyl-N′-3-dimethylaminopropyl carbodiimide. N-chloroacetylated threonine derivatives, on the other hand, do not form oxazolones so readily. The N-acetylated oxazolones are easily epimerized and lead to diastereoisomeric mixtures of threonine derivatives on hydrolysis with dilute
Ñ -Acetylated苏氨酸衍生物,具有叔丁基或苄基类的侧链保护,形成与治疗可分离-5(4H)-oxazolones Ñ乙基Ñ '-3-二甲氨基丙基碳化二亚胺。另一方面,N-氯乙酰化苏氨酸衍生物不那么容易形成恶唑酮。所述Ñ -acetylated恶唑酮容易差向异构化,并导致与稀酸水溶液水解苏氨酸衍生物的非对映体混合物。这些混合物的成分可以色谱分离,但对于O来说是有用的替代方法使用猪肾酰基转移酶对苄基混合物进行选择性酶水解。这些化学转化为的非蛋白原保护的衍生物的实用合成提供了基础同种异体-threonines,适合用于肽合成中使用。