Total synthesis of antitumor agent at-125, (αS,5S)-α-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid
作者:Jack E. Baldwin、Jin K. Cha、Lawrence I. Kruse
DOI:10.1016/s0040-4020(01)96774-2
日期:1985.1
A short and efficient totalsynthesis of racemic AT-125 and its racemic threo isomer proceeds via an intramolecular Michael cyclization of a protected α,β-dehydroglutamic acid γ-hydroxamate. Separation of diastereomers and deprotection to racemic AT-125 followed by enzymatic resolution of the N-chloroacetamide with hog-kidney acylase provides the natural αS,5S isomer.
simple and efficient method for the synthesis of dehydroamino acidsfromserine and threonine is reported. Various O-Cbz and O-Eoc derivatives of serine and threonine are prepared using CbzCl and EocCl, respectively, and are subjected to an anti-selective elimination on treatment with K2CO3 in DMF at 65 °C to afford dehydroalanine and dehydroamino butyric acidderivatives, respectively, in excellent yields
据报道,一种简单有效的从丝氨酸和苏氨酸合成脱氢氨基酸的方法。各种Ò -Cbz和ö丝氨酸-Eoc衍生物和苏氨酸分别使用CbzCl和EocCl,制备,并且经受抗-选择性消除治疗以K 2 CO 3在DMF中在65℃下,得到脱氢丙氨酸和脱氢丁酸酸衍生物,分别具有优异的收率。这些丝氨酸和苏氨酸的碳酸盐衍生物的高稳定性使得它们可以作为受保护的丝氨酸和苏氨酸残基用于正常的肽合成中。通过掺入O -Cbz或O合成的肽-Eoc衍生物在所报道的条件下容易消除,从而以极好的收率得到相应的脱氢肽。反应条件足够温和,不会引起肽中存在的其他立体异构中心的外消旋化。
A Stereospecific Elimination to Form Dehydroamino Acids: Synthesis of the Phomopsin Tripeptide Side Chain
作者:Michelle M. Stohlmeyer、Hiroko Tanaka、Thomas J. Wandless
DOI:10.1021/ja991037q
日期:1999.6.1
An increasing interest in R,â-dehydroamino acids has developed in recent years based both on their importance as commodity chemicals and their presence in biologically activenatural products. Efficient methods for the asymmetric hydrogenation of R,â-dehydroamino acids allow access to a wide variety of unnatural amino acids.1 Dehydroamino acids are also found in many natural products including the antrimycins