5-Fluorouracil → 2,4-Dichloro-5-fluoropyrimidine

Participants

Reaction Steps

To a stirred mixture of 5-fluoropyrimidine-2,4(1H,3H)-dione (3.0 g, 23 mmol) and phosphorous pentachloride (14.41 g, 69 mmol) was added phosphorous oxychloride (12.6 mL, 130 mmol). The reaction mixture was stirred and heated to reflux for 5 hours and then cooled to ambient temperature and stirred overnight. The mixture was carefully poured onto ice/water (600 mL) and then stirred for 1 hour. Sodium chloride was added and the product was extracted into dichloromethane. The combined organic layer was dried (MgSO4), filtered and evaporated to give the title compound (84%) as a yellow solid.

Provenance & Evidence