Phosphorus oxychloride → 6-Bromo-4-chlorothieno[2,3-d]pyrimidine

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Reaction Steps

6-Bromo-3H-thieno[2,3-d]pyrimidin-4-one (11.64 g, 0.05 mol) was added portion-wise to phosphoryl chloride (220 ml) and the resulting mixture was heated under reflux for 6 hours. The excess phosphoryl chloride was then removed in vacuo. The resulting residue was dissolved in dichloromethane (250 ml) and washed with water (2×100 ml), followed by saturated sodium hydrogen carbonate solution (100 ml). The organic layer was then dried (MgSO4) and the solvent was removed in vacuo to give 6-bromo-4-chlorothieno[2,3-d]pyrimidine (9.06 g) as a yellow solid, which was used without further purification.

Provenance & Evidence