The differentially protected 2-thiazolyl amino ketones 3 and 7 obtained in high yield from the L-threonine derived methyl ester 2 and 2-lithiothiazole serve as key intermediates to aldehydes 6 and 11 by syn- and anti-stereoselective reduction (diastereoselectivity 95%) of the carbonyl and liberation of the formyl group from the thiazole ring; the latter compounds are smoothly oxidized to acids 12 and 13.
从
L-苏氨酸衍生的甲基酯2和2-
锂噻唑获得的高产率差异保护的2-
噻唑基
氨基酮3和7作为关键中间体,通过对羰基的侧面和反面立体选择性还原(立体异构选择性95%)以及从
噻唑环中释放
甲醛基,生成醛6和11;后者化合物顺利氧化成酸12和13。