Phosphorus oxychloride → 4-Chloro-7-methylpyrido[2,3-d]pyrimidine

Participants

Reaction Steps

To a solution of 7-Methyl-pyrido[2,3-d]pyrimidin-4-ol (0.78 g, 4.84 mmol) in DCE (30 mL) was added DIEA (1.0 mL, 1.19 mmol), followed by POCl3 (2.4 mL, 26.1 mmol). The mixture was refluxed overnight. After cooling, the solvent was removed and the residue was dissolved in water (50 mL) and extracted with ethyl acetate (3×100 mL). The organic phase was dried and concentrated. The residue was subject to column chromatography, eluted by hexane/ethyl acetate (2:1) to give 4-Chloro-7-methyl-pyrido[2,3-d]pyrimidine (0.66 g, 76%). 1H NMR (CDCl3, 400 MHz) δ 9.22 (s, 1H), 8.49 (d, J=8.8 Hz, 1H), 7.57 (d, J=8.4 Hz, 1H), 2.88 (s, 3H). MS (APCI+) [M+H]+180.

Provenance & Evidence