A process for preparing [(1R,2R)-4-oxo-1,2-cyclopentanedicarboxylic acid II, by the resolution of racemic 4-oxo-1,2-cyclopentanedicarboxylic acid (V), said process comprising:
(a) reacting 4-oxo-1,2-cyclopentanedicarboxylic acid (V) with brucine or (1R,2S)-(−)-ephedrine, thus preparing the bis-brucine or bis-(1R,2S)-(−)-ephedrine salt of (V), and
(b) precipitating selectively the bis-brucine or bis-(1R,2S)-(−)-ephedrine salt of (1R,2R)-4-oxo-1,2-cyclopentanedicarboxylic acid II, while the bis-brucine or bis-(1R,2S)-(−)-ephedrine salt of [(1S,2S)-4-oxo-1,2-cyclopentanedicarboxylic acid stays in solution;
(c) liberating the acid II by removal of brucine or (1R,2S)-(−)-ephedrine from the precipitated salt obtained in step (b).
一种制备[(1R,2R)-4-氧代-1,2-
环戊烷二
羧酸II]的方法,通过拆分混合物中的4-氧代-1,2-
环戊烷二
羧酸(V)得到,该方法包括:(a)将4-氧代-1,2-
环戊烷二
羧酸(V)与
金雀碱或(1R,2S)-(-)-
麻黄碱反应,从而制备出(V)的双
金雀碱或双(1R,2S)-(-)-
麻黄碱盐,(b)有选择地沉淀(1R,2R)-4-氧代-1,2-
环戊烷二
羧酸II的双
金雀碱或双(1R,2S)-(-)-
麻黄碱盐,而双
金雀碱或双(1R,2S)-(-)-
麻黄碱盐的[(1S,2S)-4-氧代-1,2-
环戊烷二
羧酸]保持在溶液中;(c)通过从步骤(b)中沉淀的盐中去除
金雀碱或(1R,2S)-(-)-
麻黄碱来释放酸II。