Synthesis of pure enantiomers of cis- and trans-3-(trifluoromethyl) pyroglutamic esters
作者:Detlef Gestmann、André J. Laurent、Eliane G. Laurent
DOI:10.1016/s0022-1139(96)03455-0
日期:1996.9
hydrolysis gives the cis/trans-3-(trifluoromethyl) pyroglutamates. The enantiomerically pure Schiff base, prepared from chiral 2-hydroxy-3-pinanone and t-butyl glycinate, reacts with trans-ethyl-4,4,4-trifluorocrotonate to produce four diastereoisomers which may be separated and hydrolysed to give enantiomerically pure cis- and trans-3-(trifluoromethyl)pyroglutamate.
根据实验条件,将来自甘氨酸酯的外消旋席夫碱N-(二苯基亚甲基)甘氨酸乙酯(2)添加到4,4,4-三氟巴豆酸乙酯中,得到一个或两个迈克尔加合物。酸性水解得到顺式/反式-3-(三氟甲基)焦谷氨酸酯。对映体纯的席夫碱是由手性2-羟基-3-吡喃酮和甘氨酸叔丁酯制备的,与反式-4,4,4-三氟丁烯酸乙酯反应生成四种非对映异构体,可以将其分离和水解,得到对映体纯的顺-和反式-3-(三氟甲基)焦谷氨酸。