Iodoethane → 4-Chloro-5-ethyl-5H-pyrrolo[3,2-d]pyrimidine

To a suspension of 4-chloro-5H-pyrrolo[3,2-d]pyrimidine (200 mg) in N,N-dimethylformamide (1.3 mL) was added potassium carbonate (269 mg) under ice-cooling, and the mixture was stirred while warming to room temperature for 15 min. Iodoethane (305 mg) was added to the reaction mixture, and the mixture was stirred at room temperature for 3 hrs. The reaction mixture was diluted with water (20 mL) and extracted with ethyl acetate (30 mL×3). The organic layer was washed with saturated brine (20 mL×3) and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the obtained residue was subjected to silica gel column chromatography (silica gel, eluent:hexane/ethyl acetate=80/20→10/90). The object fraction was concentrated under reduced pressure and dried to give the title compound (187 mg) as a pale-yellow solid.