A mixture of N-(1-cyclohexylmethylpiperid-4-yl)-2-methoxy-4-acetamido-5-chlorobenzamide hydrochloride monohydrate (10 g; 0.02 moles), concentrated hydrochloric acid (6 ml) and water (20 ml) was boiled under reflux for 1.5 hours. The solution was then made alkaline with sodium hydroxide solution and extracted with chloroform. The organic solution was dried (Na2SO4) and the solvent removed in vacuo to give N-(1-cyclohexylmethylpiperid-4-yl)-2-methoxy-4-amino-5-chlorobenzamide (7.1 g), m.p. 213°-215° C. after recrystallization from methanol.
