Patent ID: 9227965
Filing Date: 2016-01-05
CPC Classification: A61P,C07C,C07D

Claim Text:
1. A process for the preparation of a cinchonidine salt of formula (IV) comprising the steps of: (a) subjecting 4-oxo-1,2-cyclopentanedicarboxylic acid (V) to reduction in an aqueous environment, thus providing an aqueous solution of racemic 4-hydroxy-1,2-cyclopentanedicarboxylic acid (VI); (b) adding an organic solvent to the aqueous solution obtained in (a) without separation of VI from the aqueous solution; (c) subjecting the racemic hydroxyacid (VI) to cyclization so as to obtain an aqueous-organic solvent solution of the corresponding racemic lactone acid (II); (d) adding cinchonidine to the aqueous-organic solvent solution obtained in (c) so as to obtain the cinchonidine salt (III) of the lactone acid; (e) allowing the cinchonidine salt to crystallize so as to obtain the enantiomerically purified crystalline lactone acid cinchonidine salt (IV), the numbered formulae herein being as follows: