280582-23-2

37454-52-7

280582-23-2

5-Morpholinopyrimidine-2,4(1H,3H)-dione (2.98 g, 15.1 mmol) was used as a raw material and mixed with triethylamine hydrochloride (6.24 g, 45.3 mmol) in 35 mL of phosphorus trichloride. The reaction mixture was stirred at 0 °C and subsequently warmed up to 80 °C for 4 days and then refluxed for 3 hours. Upon completion of the reaction, the solvent was removed by evaporation and azeotroped with toluene to further remove the residual solvent. The residue was diluted with ethyl acetate, cooled to 0 °C and the reaction was carefully quenched with ice water. Subsequently, the organic layer was washed with sodium bicarbonate solution and brine, dried with anhydrous sodium sulfate, and the solvent was evaporated. Purification by fast column chromatography (silica gel, eluent 1:3 ethyl acetate/hexane) afforded 4-(2,4-dichloropyrimidin-5-yl)morpholine (3.18 g, 90% yield) as a white solid. The structure of the product was confirmed by 1H-NMR (500 MHz, CDCl3) δ 8.25 (s, 1H), 3.90 (m, 4H), 3.20 (m, 4H) ppm; mass spectrometry (FIA) m/z 234.0/236.0 (M+H)+; and HPLC (Method A) retention time 2.930 min.