A New Method for the Synthesis of (S)-α-Methylisoserine and Its Incorporation into Peptides
作者:Raul Pires、Klaus Burger
DOI:10.1055/s-1996-4387
日期:1996.11
(S)-(+)-Citramalic acid is converted into isocyanate 4 using hexafluoroacetone as the protecting agent. Isocyanate 4 represents a doubly activated species, which upon reaction with alcohols provides N-protected, carboxyl-activated α-methylisoserine derivatives, perfectly suited for peptide synthesis (5 → 8). Acylation of 4 with N-protected amino acids gives fully protected carboxyl-activated dipeptides. Ring opening with amino acid esters results in the formation of tripeptides (9 → 10).
(S)-(+)-柠檬酸被转化成异氰酸酯4,使用六氟丙酮作为保护剂。异氰酸酯4是一种双重活化的物质,当其与醇反应时,产生了N-保护、羧基活化的α-甲基异丝氨酸衍生物,非常适合用于多肽合成(5 → 8)。用N-保护的氨基酸对4进行酰化作用,得到完全保护的、羧基活化的二肽。用氨基酸酯进行环开反应,形成了三肽(9 → 10)。