4,6-Dichloro-5-nitropyrimidine

2164-83-2

4316-93-2

The general procedure for the synthesis of 4,6-dichloro-5-nitropyrimidine using 5-nitro-4,6-dihydroxypyrimidine as starting material was as follows: to a suspension of phosphoryl chloride (96 mL, 1056 mmol) containing 4,6-dihydroxy-5-nitropyrimidine (25 g, 160 mmol) was added dimethylaniline (32.6 mL, 246 mmol). The reaction mixture was heated in an oil bath at 125 °C and subsequently warmed to 130 °C and held for 1 hour. Upon completion of the reaction, excess trichlorophosphorus oxide was removed by evaporation. The residue was slowly poured onto ice (300 g) and the solid formed was subsequently collected by filtration. The filtrate was extracted with ether and the combined organic layers were washed sequentially with water and brine and dried with anhydrous sodium sulfate. After removal of the solvent by evaporation, the residue was purified by fast column chromatography in dichloromethane to afford the light brown solid product 4,6-dichloro-5-nitropyrimidine (21.5 g, 70% yield). The 1H NMR (DMSO-D6) data of the product were as follows: δ 8.3 (s, 1H, Ar).