Sulfuric Acid → 6-(2,6-dichloro-phenyl)-8-phenyl-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-(2,6-dichloro-phenyl)-propionic acid methyl ester (0.18 g, 0.36 mmol) (from Example 2b supra) in glacial acetic acid (2 mL) was added concentrated sulfuric acid (0.1 mL) in one portion. The reaction mixture was heated at 135° C. overnight and 145° C. for another 4 hours. 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-(2,6-dichloro-phenyl)-8-phenyl-2-phenylamino-5,8-dihydro-6H-pyrido[2,3-d]pyrimidin-7-one as a gray solid. (Yield 61.2 mg, 36.3%).

Provenance & Evidence