Preparation of a protected (2S,3S)-.beta.-hydroxyaspartic acid suitable for solid-phase peptide synthesis
作者:Rolf Wagner、Jefferson W. Tilley
DOI:10.1021/jo00313a015
日期:1990.12
(2S,3S)-N-Boc-3-(benzyloxy)aspartic acid beta-benzyl ester (2), a beta-hydroxyaspartic acid derivative suitably protected for incorporation into peptides by solid-phase synthesis, was synthesized from N-Boc-(R)-serine via the intermediate, [4R-(R*,R*)]-4-[hydroxy[2-(trimethylsilyl)ethynyl]methyl]-2,2-dimethyl-3-oxazolidinecarboxylic acid 1,1-dimethylethyl ester (5). Key transformations involved the ruthenium tetraoxide mediated oxidation of the ethynyl moiety to form the beta-carboxylic acid and, after esterification and oxazolidine ring hydrolysis, dichromate oxidation of the resulting primary alcohol to the alpha-carboxylic acid. The method is suitable for the preparation of gram quantities of 2.
(2S,3S)-N-Boc-3-(苯甲氧基)天冬氨酸β-苄酯(化合物2)是一种适合通过固相合成法引入肽中的β-羟基天冬氨酸衍生物。该化合物由N-Boc-(R)-丝氨酸通过中间体[4R-(R*,R*)]-4-[羟基(2-(三甲基硅基)炔基)甲基]-2,2-二甲基-3-氧杂环戊烷羧酸1,1-二甲基乙基酯(化合物5)合成而来。
关键转换步骤包括:1) 四氧化钌催化的氧化反应,将炔基部分氧化生成β-羧酸;2) 酯化和氧杂环戊烷环水解后,使用重铬酸氧化所得的伯醇生成α-羧酸。
该方法适用于制备克级规模的化合物2。