Hydrochloric Acid → (4aR,8aS)-8a-(2,4-difluorophenyl)-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-amine

Participants

Reaction Conditions

Reaction Steps

A suspension of 9H-fluoren-9-ylmethyl {[(3S,4R)-3-(2,4-difluorophenyl)-4-(hydroxymethyl)tetrahydro-2H-pyran-3-yl]carbamothioyl}carbamate (C12) (1.417 g, 2.701 mmol) in methanol (20 mL) was treated with concentrated hydrochloric acid (12 M, 0.675 mL, 8.10 mmol) and heated at 70° C. for 2 hours. The reaction mixture was concentrated in vacuo, dissolved in dichloromethane and washed with saturated aqueous sodium bicarbonate solution. The organic layer was dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The residue was dissolved in acetonitrile (20 mL) and treated with piperidine (2 mL); this reaction mixture was stirred at room temperature for 18 hours, and then concentrated in vacuo. Purification via silica gel chromatography (Gradient: 0% to 7% methanol in dichloromethane) provided the product as a white solid. Yield: 281 mg, 0.988 mmol, 37%. LCMS m/z 285.0 (M+1). 1H NMR (400 MHz, CD3OD) δ 1.45-1.52 (m, 1H), 1.99-2.12 (m, 1H), 2.67-2.73 (m, 1H), 2.82-2.90 (m, 2H), 3.62-3.70 (m, 1H), 3.63 (br d, J=10.9 Hz, 1H), 3.99-4.05 (m, 2H), 6.92-7.00 (m, 2H), 7.35 (ddd, J=9.5, 8.7, 6.7 Hz, 1H).

Provenance & Evidence