| abstract |
The present invention relates to a process for purifying the methyl estern2- [4- (2- (1-piperidinyl) ethoxy) benzoyl] benzoic acid,nwhose hydrochloride isnknown spasmolytic, pitofenone hydrochloride.nThe main impurity accompanying the crude base isn2- [4- (2- (1-piperidinyl) ethoxy) benzoyl] benzoic acid 2-piperidinoethyl ester,nwhich is being convertednby re-sterilizing in methanolncatalysing the basicity of its own molecule to the desirednmethyl ester. Conditions under which transesterification occursnperformed, ensure a decrease in impurity contentnfar below the allowable limit and the product isnthey usually do not have to crystallize. |