Patent ID: 6486325
Filing Date: 2002-11-26
Classification: A61P,C07C,C07D

Abstract:
A process for preparing a mixture of compounds of formulae Ia and Ib: enriched in the compound of formula Ia, and pharmaceutically acceptable salts thereof, whereinR1 is C1-C6 alkyl; R2 is C1-C6 alkyl, halo C1-C6 alkyl or phenyl or substituted phenyl; R3 is hydrogen or halo; m is zero, one or two; comprising the steps of(a1) reacting a mixture of compounds of formulae Ia and Ib: â€ƒwith an acid of formula HX, wherein HX is selected from the group consisting of (S)-(+)-mandelic acid, D-(âˆ’)-tartaric acid, di-p-toluoyl-D-tartaric acid, ((1R)-endo,anti)-(+)-3-bromocamphor-8-sulfonic acid, quinic acid, acetic acid and hydrobromic acid, to form a mixture of diastereomeric compounds of formulae Va and Vb, respectively: (b1) permitting the HX salt of the diastereomeric product mixture of step (a1) to crystallize out of a solution thereof in an appropriate solvent; (c1) treating the resulting mixture of compounds obtained from step (b1) with a base to obtain a mixture of compounds Ia and Ib, that is enriched in the compound of formula Ia.