Salicylamide → 1'-benzylspiro[1,3-benzoxazine-2,4'-piperidin]-4(3H)-one

Participants

Reaction Steps

Salicylamide (7.24 g), 1-benzylpiperidin-4-one (10.0 g) and p-toluenesulfonic acid hydrate (500 mg) were suspended in toluene (200 mL), and the suspension was stirred under reflux overnight while removing the water in the reaction system using a Dean-Stark tube. The mixture was cooled to room temperature, and the resulting precipitate was collected by filtration and washed with water, ethanol and diethyl ether to give 1′-benzylspiro[1,3-benzoxazine-2,4′-piperidin]-4(3H)-one as a crude product (9.7 g). The obtained crude 1′-benzylspiro[1,3-benzoxazine-2,4′-piperidin]-4(3H)-one (5.0 g) and 10% palladium-carbon (1.0 g) were suspended in ethanol (50 mL), and the suspension was stirred at 50° C. for 5 hr under a hydrogen atmosphere. The catalyst was removed by filtration through celite and the solvent was evaporated under reduced pressure. The resulting precipitate was collected by filtration, and washed with ethanol and diethyl ether to give the object product (2.7 g, 77%).

Provenance & Evidence