Hydrochloric Acid → 5,6-Dihydro-2H-thiopyran-3-carboxamide

Participants

Reaction Steps

To a solution of 5,6-dihydro-2H-thiopyran-3-carboxylic acid (0.84 g, 5.8 mmol) in DMF (29 mL) was added DIPEA (3.4 g, 26 mmol), followed by TBTU (4.1 g, 13 mmol). The resulting mixture was stirred at ambient temperature for 30 minutes, then HMDS (2.1 g, 13 mmol) was added. The mixture was stirred at ambient temperature for 16 hours. The reaction mixture was acidified with 1N aqueous HCl, and extracted with EtOAc (3×). The combined organic extracts were again washed with 1N aqueous HCl, brine, dried over anhydrous Na2SO4, filtered, and concentrated in vacuo. The crude residue was purified by MPLC on silica gel (using a gradient elution of 0-5% MeOH/DCM). Desired fractions were identified, combined and concentrated in vacuo to afford the title compound. 1H NMR (500 MHz, CDCl3): δ 6.68-6.69 (m, 1H); 3.38 (q, J=2.2 Hz, 2H); 2.70 (t, J=5.8 Hz, 2H); 2.50-2.51 (m, 2H).

Provenance & Evidence