| abstract |
1,182,008. Resolution of dl-(3-trifluoromethylphenoxy)(4-chlorophenyl) acetic acid. MERCK & CO. Inc. 27 Sept., 1967 [3 Oct., 1966], No. 44021/67. Heading C2C. Resolution of dl-(3-trifluoromethylphenoxy) (4-chlorophenyl) acetic acid is effected by treating the racemic acid with cinchonidine to form crystalline d-(3-trifluomethylphenoxy) (4-chlorophenyl) acetic acid cinchonidine salt, separating the salt from the liquor and treating the salt with acid to obtain pure disomer; allowing the liquor to stand for a protracted period to precipitate the l-acid isomer cinchonidine salt and treating the salt with acid to obtain l-isomer. The salts are preferably washed with a C 1-6 alkanol before treatment with the acid, e.g. H 2 SO 4 . |