A process provided for the preparation of the (S)— and (R)-alpha-ethyl-2-oxo-1-pyrrolidineacetamide of formula:(1) from (RS)-alpha-ethyl-2-oxo-1-pyrrolidineacetic acid of formula:(2) comprising: i) combining the (RS)-2 with a chiral base (resolving agent) in a resolution solvent and crystallizing from the said mixture the diastereomeric salt of (S)— or (R)-2 and chiral base; ii) regenerating (S)— or (R)-2 from the crystallized diastereomeric salt by treating with a suitable acid or acidic ion-exchange resin; iii) optionally regenerating (R)— or (S)-2 or their mixture (predominantly one enantiomer) from the crystallization mother liquor by treating with a suitable acid or acidic ion-exchange resin; iv) optionally epimerizing (RS)-2 by treating (R)— or (S)-2 or their mixture (predominantly one enantiomer) of step iii with an acid anhydride; V) optionally converting (RS)-2 of step iv into enantiomerically enriched (S)— or (R)-2 through steps i and ii; vi) formation of the mixed anhydride by reacting (R)— or (S)-2 with an alkyl or aryl sulfonyl halogen compound RSO2X in the presence of a suitable base; and vii) reacting the mixed anhydride with ammonia; wherein R represents C 1 to C 15 alkyl or aryl groups such as methyl, ethyl, p-toluenyl, 2,4,6-trimethylbenzyl, 2,4,6-trichloribenzyl, and X represents a halogen atom such as F, Cl and Br atoms.
提供了一种从式(2)的(RS)-α-乙基-2-氧代-1-
吡咯烷乙酸制备式(1)的(S)-和(R)-α-乙基-2-氧代-1-
吡咯烷乙酰胺的方法,包括:i)将(RS)-2与手性碱(分离剂)在分离溶剂中混合,并从所述混合物中结晶出(S)-或(R)-2和手性碱的非对映异构盐;ii)通过用适当的酸或酸性离子交换
树脂处理结晶得到的非对映异构盐来再生(S)-或(R)-2;iii)通过用适当的酸或酸性离子交换
树脂处理结晶母液中的(R)-或(S)-2或它们的混合物(主要是一种对映体)来可选地再生(R)-或(S)-2或它们的混合物(主要是一种对映体);iv)通过用酸酐处理步骤iii中的(R)-或(S)-2或它们的混合物(主要是一种对映体)可选地使(RS)-2外消旋化;v)通过步骤i和ii将步骤iv中的(RS)-2转化为对映富集的(S)-或(R)-2;vi)通过在适当的碱存在下,将(R)-或(S)-2与烷基或芳基
磺酰卤化物RSO2X反应形成混合酸酐;vii)将混合酸酐与
氨反应;其中R代表C1到C15的烷基或芳基基团,例如甲基、乙基、
对甲苯基、2,4,6-三甲基苯基、2,4,6-
三氯苯基,X代表卤素原子,例如F、Cl和Br原子。