Thionyl Chloride → 4-Chlorothieno[2,3-d]pyrimidine

Participants

Reaction Steps

A mixture of thieno[2,3-d]pyrimidin-4-ol derivative 3 (3.7 mmol), thionyl chloride (5.5 mL) and dry DMF (0.5 mL) was heated at reflux for 4 h. The reaction mixture was cooled to room temperature and the excess thionyl chloride was removed by vacuum distillation. To the resulting residue 200 g of ice was added and extracted with dichloromethane (3×100 mL). The combined organic layers were dried (Na2SO4) and concentrated. The product was purified by silica chromatography (100% DCM) to afford 4-Chloro-thieno[2,3-d]-pyrimidine 4 in 80-95% yields.

Provenance & Evidence