24424-99-5

28783-38-2

165947-52-4

4,5,6,7-tetrahydrothieno[2,3-c]pyridine hydrochloride (15.0 g, 85.38 mmol) and triethylamine (24.0 mL, 170.77 mmol) were used as raw materials and dissolved in dichloromethane (150 mL). Subsequently, di-tert-butyl dicarbonate (22.36 g, 102.46 mmol) was added to the reaction system. The reaction mixture was stirred at room temperature for 4.5 hours. Upon completion of the reaction, the reaction system was quenched by adding water (50 mL) to the reaction system and subsequently extracted with dichloromethane (30 mL x 2). The organic phases were combined and washed sequentially with water (20 mL × 2) and saturated brine (30 mL), and the organic layer was dried with anhydrous sodium sulfate. After filtration, the solvent was removed by evaporation under reduced pressure, and the crude product obtained was purified by column chromatography (petroleum ether/ethyl acetate, v/v = 20/1) to finally obtain the white solid product tert-butyl 4,5-dihydrothieno[2,3-c]pyridine-6(7H)-carboxylate (20.49 g, 100% yield).