Patent ID: 6303792
Filing Date: 2001-10-16
Classification: C07D

Abstract:
A process for separating a compound of formula I ##STR3##from a solution comprising water, at least one organic solvent, a compound of formula I, and n-(4-trifluoromethylphenyl)-2-cyano-3-hydroxycrotonamide, comprisinga) quantitatively determining the amount of N-(4-trifluoromethylphenyl)-2-cyano-3-hydroxycrotonamide in the solution,b) adding base corresponding to from about 50 mol % to about 150 mol % of the amount of the quantitatively determined N-(4-trifluoromethylphenyl)-2-cyano-3-hydroxycrotonamide,c) crystallizing the compound of formula I, andd) separating the resulting crystals of the compound of formula I from the solution.