p-Toluenesulfonic acid → 2-(4-hydroxy-3,5-dimethylphenyl)-5,7-dimethoxypyrido[2,3-d]pyrimidin-4(3H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-amino-4,6-dimethoxy-nicotinamide (1.40 g, 7.1 mmol) and 4-hydroxy-3,5-dimethylbenzaldehyde (1.07 g, 7.1 mmol) in N,N-dimethyl acetamide (20 mL), NaHSO3 (1.39 g, 7.81 mmol) and p-TSA (0.675 g, 3.55 mmol) were added and the reaction mixture was heated at 150° C. overnight. The solvent was removed under reduced pressure. The residue was diluted with water and the solid was collected and further washed with methanol. The crude product was purified by column chromatography (silica gel 230-400 mesh; 2% methanol in CH2Cl2 as eluent) to give 2-(4-hydroxy-3,5-dimethylphenyl)-5,7-dimethoxypyrido[2,3-d]pyrimidin-4(3H)-one (0.92 g, 39.6%). Selected data: MS (ES) m/z: 328.07; MP 297-299° C.

Provenance & Evidence