Phosphorus oxychloride → 4-Chloropyrido[2,3-d]pyrimidine

Participants

Reaction Steps

A mixture of pyrido[2,3-d]pyrimidin-4(3H)-one (1.471 g, 10 mM) and POCl3 (16 ml) is stirred for 1 h at reflux. The excess of POCl3 is removed under vacuum. Then dichloromethane and iced water is added and the mixture stirred until the black solid dissolves. The organic layer is separated, washed with bicarbonate solution, dried over Na2SO4 and then evaporated to dryness. The yellow residue is recrystallized from toluene/hexane to give almost pure title compound in 70% yield. mp 137° C.

Provenance & Evidence