Patent ID: 7273947
Filing Date: 2007-09-25
Classification: A61P,C07C

Abstract:
1. A process for reducing the ethyl 3-dimethylamino-2-phenyl-propionate content of a cis/trans mixture of ethyl 2-dimethyl-amino-1-phenyl-3-cyclohexene-1-carboxylate which is contaminated with said phenylpropionate, which process comprises selectively converting the ethyl 3-dimethylamino-2-phenyl-propionate into ethyl atropate by eliminating dimethyl amine without essentially affecting the cis/trans ratio of the ethyl 2-dimethylamino-1-phenyl-3-cyclohexene-1-carboxylate by providing a solution of the contaminated cis/trans mixture of the ethyl 2-dimethylamino-1-phenyl-3-cyclohexene-1-carboxylate in a water immiscible solvent, adding to said solution a carboxylic acid in amounts of from 0.75 to 2.0 equivalents per mole of the ethyl 2-dimethylamino-1-phenyl-3-cyclohexene-1-carboxylate, and stirring the resulting reaction mixture for 0.5 to 2 hours at a temperature of from 50° C. to 100° C.