A mixture of 26 g (0.1 mol) of α-(4-pyridyl)-benzhydrol, 1.5 g of platinum
oxide, and 250 ml of glacial acetic acid is shaken at 50-60°C under hydrogen
at a pressure of 40-50 lb/in2. The hydrogenation is complete in 2 to 3 hours.
The solution is filtered and the filtrate evaprated under reduced pressure. The
residue is dissolved in a mixture of equal parts of methanol and butanone and
0.1 mol of concentrated hydrochloric acid is added. The mixture is cooled and
filtered to give about 30 g of α-(4-piperidyl)benzhydrol hydrochloride, MP 283-
285°C, as a white, crystalline substance.
The free base is readily obtained from the hydrochloride salt by treatment
with ammonia and when so obtained has a melting point of 160-161°C.
