Methanesulfonic Acid → 6,6-Diphenylpiperidin-2-one

Participants

Reaction Steps

A stirred mixture of 24. g (0.17 tool) of granular phosphorus pentoxide and 240.g (2.5 mol) of 98% methanesulfonic acid was maintained at 110 ° C. until all the solid dissolved (1 hour) . To this solution was added in portions over several minutes 12 g (0.05 mol) of 5,5-diphenyl-4-pentenenitrile. The resulting dark mixture was heated for 5 minutes longer and then carefully added to an ice-cooled vigorously stirred mixture of 1 liter of saturated aqueous sodium bicarbonate and 1 liter of ethyl acetate. The basic aqueous phase was extracted with 3×500 ml of fresh ethyl acetate, the organic layers were combined, washed with 2×500 ml of water, 1×500 ml brine, and dried over sodium sulfate. The resulting crude solid was recrystallized from toluene to give 8.5 g (66%) of 6,6-diphenyl-2-piperidinone as a white solid (mp 193°-196° C.) .

Provenance & Evidence