1053656-51-1

16982-21-1

188869-05-8

1053656-51-1

General procedure for the synthesis of ethyl 5-Boc-4,5,6,7-tetrahydrothiazolo[5,4-c]pyridine-2-carboxylate from ethyl thiooxalate and N-Boc-3-bromo-4-oxo piperidine: N-Boc-3-bromo-4-oxo piperidine (4.0 g, 14.4 mmol) was dissolved in isopropanol (IPA, 25 mL). Ethyl thiooxalate (1.60 g, 12.0 mmol) and sodium bicarbonate (NaHCO3, 2.01 g, 24.0 mmol) were added. The reaction mixture was heated to reflux for 12 hours and subsequently concentrated under reduced pressure. The residue was dissolved in water (63 mL) and extracted with dichloromethane. The organic layer was washed sequentially with water and saturated saline, dried over anhydrous sodium sulfate (Na2SO4), and concentrated under reduced pressure to afford the target compound, ethyl 5-Boc-4,5,6,7-tetrahydrothiazolo[5,4-c]pyridine-2-carboxylate (2.2 g, 60% yield), which was pure enough to be used in the subsequent reaction directly. The product characterization data were as follows: melting point: 138-140 °C; 1H NMR (300 MHz, CDCl3): δ 4.71 (s, 2H), 4.48 (q, J = 12Hz, 2H), 3.72 (m, 2H), 2.96 (t, J = 5.4Hz, 2H), 2.41 (t, J = 6.3Hz, 2H), 1.51 (s, 9H) , 1.44 (t, J = 1.2 Hz, 3H); MS (ESI) m/z: 335.1 [M + Na]+.