Syntheses of Optically Active, Protected and Unprotected Vinylglycines.
作者:Taisuke ITAYA、Shigeyuki SHIMIZU、Satoshi NAKAGAWA、Masatoshi MORISUE
DOI:10.1248/cpb.42.1927
日期:——
Vinylglycine (2) has been shown to undergo racemization under acidic conditions. Optically pure 2 was obtained from 2·HCl by enzymatic hydrolysis through N-acetylvinylglycine (5), followed by recrystallization. (S)-N-(Methoxycarbonyl)vinylglycine (6) was configurationally so unstable under acidic conditions that 6 could not be obtained from 2 in an optically pure form. On the other hand, configurationally stable (S)-N-(9-phenylfluoren-9-yl)vinylglycine methyl ester (9) was synthesized from (S)-homoserine; 9 was hydrolyzed with sodium hydroxide to afford the carboxylic acid 10 of more than 99% ee.
乙烯基甘氨酸(2)在酸性条件下会发生消旋化。通过酶水解 N-乙酰乙烯基甘氨酸 (5),然后重结晶,从 2-HCl 中得到了光学纯度为 2 的乙烯基甘氨酸。(在酸性条件下,(S)-N-(甲氧羰基)乙烯基甘氨酸(6)的构型非常不稳定,因此无法从 2 中得到光学纯的 6。另一方面,从(S)-高丝氨酸合成了构型稳定的(S)-N-(9-苯基芴-9-基)乙烯基甘氨酸甲酯(9)。