31169-25-2

31169-27-4

General procedure for the synthesis of 7-bromo-4-chlorothieno[3,2-d]pyrimidines from 7-bromothieno[3,2-D]pyrimidin-4(1H)-ones: 7-bromo-3H-thieno[3,2-d]pyrimidin-4-one (191, 153.0 mg, 0.66 mmol) was dissolved in phosphorochloridic acid (2 mL) and refluxed under nitrogen protection for 2 hours. After completion of the reaction, the reaction solution was cooled to room temperature and slowly poured into saturated aqueous sodium carbonate solution for neutralization. Subsequently, the aqueous phase mixture was extracted with ethyl acetate and the organic phase was washed sequentially with water and brine and dried with anhydrous magnesium sulfate. The solvent was removed by concentration under reduced pressure and the residue was dried under vacuum overnight in the presence of phosphorus pentoxide to afford 7-bromo-4-chlorothieno[3,2-d]pyrimidine (192, 156.0 mg, 95% yield, white solid).