Pyridine → N-[(4aR,6R,8aS)-6-[(benzyloxy)methyl]-8a-(5-bromo-2-fluorophenyl)-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-yl]benzamide

Participants

Reaction Conditions

Reaction Steps

A solution of N-{[(3S,4R,6R)-6-[(benzyloxy)methyl]-3-(5-bromo-2-fluorophenyl)-4-(hydroxymethyl)tetrahydro-2H-pyran-3-yl]carbamothioyl}benzamide (C31) (9.49 g, 16.2 mmol) and pyridine (4.94 mL, 61.4 mmol) in dichloromethane (278 mL) was cooled to −50° C. Trifluoromethanesulfonic anhydride (5.44 mL, 32.3 mmol) was added drop-wise to the solution and the mixture was gradually warmed to 0° C. After 2 hours, the reaction mixture was partitioned between dichloromethane (1 L) and water (500 mL). The organic layer was washed with dichloromethane (2×250 mL) and the combined organics were then washed with brine (500 mL). The resulting organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo to yield an orange oily residue. Purification via silica gel chromatography (Gradient: 0% to 60% ethyl acetate in heptane) afforded the product as an orange solid. Yield: 5.53 g, 60%. LCMS m/z 571.2 [M+H+]. 1H NMR (400 MHz, CD3OD) characteristic peaks: δ 8.12 (d, J=7.4 Hz, 2H), 7.43-5.58 (m, 5H), 7.12-7.32 (m, 6H), 4.51-4.60 (m, 2H), 4.10-4.13 (m, 1H), 3.87-3.91 (m, 1H), 3.55-3.63 (m, 2H), 3.18-3.21 (m, 1H), 2.94 (dd, J=13.2, 4.0 Hz, 1H), 2.74 (dd, J=13.1, 2.9 Hz, 1H), 1.90-1.99 (m, 1H), 1.67-1.72 (m, 1H).

Provenance & Evidence