230301-73-2

The general procedure for the synthesis of tert-butyl 6,7-dihydrothieno[3,2-C]pyridine-5(4H)-carboxylate from 4,5,6,7-tetrahydrothieno[3,2-c]pyridine hydrochloride (5 g, 28.46 mmol) and di-tert-butyl dicarbonate (6.83 g, 31.30 mmol) is as follows: 4,5,6,7-tetrahydrothieno[3,2-c] pyridine hydrochloride was suspended in 150 mL of dichloromethane, triethylamine (3.17 g, 31.30 mmol) was added followed by slow addition of solid di-tert-butyl dicarbonate. The reaction mixture was stirred at room temperature for 2 hours. After completion of the reaction, the organic phase was washed sequentially with water (2 x 100 mL) and brine (2 x 100 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to give a colorless oily product (6.8 g, 100% yield), which solidified to a white solid on standing.

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