Reaction Steps
N-[(4R,4aR,6R,8aS)-8a-(2,4-Difluorophenyl)-6-(methoxymethyl)-4-methyl-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-yl]benzamide (C20) was deprotected using the method described for conversion of N-[(4R,4aR,6R,8aS)-8a-(2,4-difluorophenyl)-6-(fluoromethyl)-4-methyl-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-yl]benzamide (C19) to (4R,4aR,6R,8aS)-8a-(2,4-difluorophenyl)-6-(fluoromethyl)-4-methyl-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-amine (1) in Example 1. In this case, the chromatography was carried out using a gradient of 0% to 10% methanol in dichloromethane; the product was isolated as a white solid. Yield: 69.3 mg, 0.202 mmol, 83%. LCMS m/z 343.2 [M+H+]. 1H NMR (400 MHz, CD3OD) δ 7.32 (ddd, J=9.6, 9.0, 6.6 Hz, 1H), 6.92-7.00 (m, 2H), 4.10 (dd, J=11.1, 2.2 Hz, 1H), 3.75-3.82 (m, 1H), 3.72 (d, J=11.1 Hz, 1H), 3.47 (dd, half of ABX pattern, J=10.3, 6.4 Hz, 1H), 3.41 (dd, half of ABX pattern, J=10.3, 3.9 Hz, 1H), 3.38 (s, 3H), 3.05-3.13 (m, 1H), 2.71-2.78 (m, 1H), 1.55-1.62 (m, 1H), 1.36-1.47 (m, 1H), 1.17 (d, J=6.8 Hz, 3H).
