2,4-Dichloro-5H-pyrrolo[3,2-d]pyrimidine

65996-50-1

63200-54-4

1H-pyrrolo[3,2-d]pyrimidine-2,4(3H,5H)-dione (0.38 g, 2.52 mmol) was used as starting material and suspended in phosphorus trichloride (30 mL). The suspension was heated to 120°C and the reaction was carried out for 6 h, during which the mixture gradually changed to a clarified homogeneous solution. Upon completion of the reaction, the mixture was cooled to room temperature and the excess phosphorus trichloride was subsequently removed under vacuum. The residue was cooled in an ice bath and cold ammonium hydroxide solution (30 mL, pH = 8) was slowly added and stirred under this condition for 30 minutes. At the end of the reaction, the precipitate was collected by filtration and washed with cold water. Finally, the resulting solid was dried under vacuum to afford the target product 2,4-dichloro-5H-pyrrolo[3,2-d]pyrimidine (0.33 g, 70% yield).