Phosphorus oxychloride → 2-Chloro-3-(4-fluorophenyl)pyrido[3,2-d]pyrimidin-4(3H)-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 3-(4-fluorophenyl)-2-thioxo-2,3-dihydropyrido[3,2-d]pyrimidin-4(1H)-one (2.6 g, 9.5 mmol) in 30 mL of POCl3 is heated to 135° C. and stirred for 2 days. After cooling to RT, the excess POCl3 is removed in vacuo, and the residue is azeotroped twice with toluene. The resulting sticky brown oil/solid mix is dissolved in CH2Cl2 and neutralized to pH 7-8 with saturated NaHCO3. The layers are separated, and the CH2Cl2 layer is dried (Na2SO4), filtered, and evaporated to give a brown sticky solid. Purification by column chromatography (gradient from CH2Cl2 to 20% EtOAc/CH2Cl2) affords the title compound as an off-white solid. 1H NMR (400 MHz, CDCl3) δ 8.91 (1H, m), 8.05 (1H, m), 7.74 (1H, m), 7.28 (4H, m).

Provenance & Evidence