Phosphorus oxychloride → 2,5-Diamino-4,6-dichloropyrimidine

Participants

Reaction Conditions

Reaction Steps

A suspension of 2,5-diamino-4,6-dihydroxypyrimidine hydrochloride (5.0 g, 28 mmol) and tetraethylammonium chloride (27.8 g, 0.167 mmol) in phosphorus oxychloride (80 ml) was heated at 105° C. for 20 hours. After cooling down to room temperature, the excess phosphorus oxychloride was distilled off under vacuum. The reaction mixture was poured into ice water and the pH was adjusted to 4, and the mixture was stirred for 1 hour at 50° C. The pH was adjusted to 7 and the product was extracted with ethyl acetate, washed with a saturated NaHCO3 solution, brine and dried over Na2SO4. After removing the solvents under reduced pressure, the residue was purified by flash chromatography on silica (CH2Cl2/MeOH 50:1), affording the title compound (3.21 g, 64%).

Provenance & Evidence