Triethylamine → N-adamantan-2-yl-2,3-dihydro-4H-1,4-benzoxazine-4-carboxamide

Participants

Reaction Steps

To a solution of triphosgene (119 mg) in chloroform (3 ml), a solution of triethylamine (332 μl) and 3,4-dihydro-2H-1,4-benzoxazine obtained in Reference Example 14 (108 mg) in chloroform (2 ml) was added under ice cooling and stirred at the same temperature for 10 minutes. To the reaction mixture, 2-adamantaneamine hydrochloride (150 mg) and triethylamine (166 μl) were then added and stirred at room temperature for 16 hours. The reaction mixture was poured into water and extracted with ethyl acetate. The organic layer was washed sequentially with 1M aqueous hydrochloric acid, saturated aqueous sodium bicarbonate and brine. After drying over anhydrous magnesium sulfate, the desiccant was filtered off and the solvent was distilled off under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluting solvent: n-hexane:ethyl acetate=4:1). The resulting residue was dissolved in a small volume of chloroform and converted into a powder form by addition of diethyl ether, and then collected by filtration to give the titled compound (Compound 34, 96 mg) as a colorless powder.

Provenance & Evidence