N-[(4R,4aR,6R,8aS)-8a-(2,4-difluorophenyl)-6-(ethoxymethyl)-4-methyl-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-yl]benzamide 、 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 、 (4R,4aR,6R,8aS)-8a-(2,4-difluorophenyl)-6-(methoxymethyl)-4-methyl-4a,5,6,8-tetrahydro-4H-pyrano[3,4-d][1,3]thiazin-2-amine 生成 (4R,4aR,6R,8aS)-8a-(2,4-difluorophenyl)-6-(ethoxymethyl)-4-methyl-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-amine