Sulfuric Acid → 6,8-diphenyl-2-phenylamino-5,8-dihydro-6H-pyrido[2,3-d]pyrimidin-7-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-(2,4-diphenylamino-pyrimidin-5-yl)-2-phenyl-propionic acid methyl ester (100 mg, 0.24 mmol) (from Example 5b supra) was added 5% concentrated sulfuric acid in glacial acetic acid (3 mL) in one portion. The reaction mixture was heated at 60° C. overnight. After cooling, the reaction mixture was diluted with ethyl acetate (50 mL) and quenched with 2 N aqueous sodium hydroxide solution. The organic layer was separated and successively washed with water (10 mL) and brine (10 mL), dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo to give the crude product which was crystallized from ethyl acetate-hexanes to give 6,8-diphenyl-2-phenylamino-5,8-dihydro-6H-pyrido[2,3-d]pyrimidin-7-one as a light brown solid. (Yield 61.2 mg, 66.2%). HRMS m/z Calcd for C25H20N4O [(M+H)+]: 393.1710. Found: 393.1714.

Provenance & Evidence