Phosphorus oxychloride → 4-Chloro-2-(methylthio)thieno[2,3-d]pyrimidine

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Reaction Conditions

Reaction Steps

2-Methylsulfanyl-3H-thieno[2,3-d]pyrimidin-4-one (12 g, 60.5 mmol) was combined with POCl3 (56 mL), and the resulting mixture was heated to reflux for about 1 hour. The reaction mixture was concentrated under reduced pressure at 50° C. The residue was diluted with ethyl acetate (700 mL) at 0° C. Saturated sodium bicarbonate solution (600 mL) was added slowly. The resulting mixture was stirred vigorously at 0° C. for one hour and the layers were separated. Saturated sodium bicarbonate solution (600 mL) was added to the organic layer at 0° C., and the mixture was stirred vigorously for 20 minutes. The layers were separated. Brine (600 mL) was added to the organic layer and stirred vigorously for 5 minutes, and the layers were again separated. The organic layer was dried over magnesium sulfate, filtered and concentrated to afford the title compound (10.7 g) as a dark tan powder (M+=216, M.P.=105.0–107.4° C.).

Provenance & Evidence