反应详情

Working in a manner similar to that described in Example 12, but starting with (5RS, 6SR)-2,6-diphenyl-6-methyl-5,6-dihydro-4H-1,3-oxazin-5-ol (0.8 g) and phenyl isocyanate (1.8 g), and after purification of the solid obtained by chromatography on a column (height: 30 cm; diameter: 2.5 cm) of silica (0.2-0.063 mm), eluting with a mixture of cyclohexane and ethyl acetate (80:20 by volume) and collecting 20cc fractions, fractions 1 to 5 being combined and concentrated to dryness under reduced pressure (4 kPa) at 45° C., followed by recrystallization of the residue in acetonitrile (12 cc), (5RS, 6SR)-6-methyl-2,6-diphenyl-5-phenylcarbamoyloxy-5,6-dihydro-4H-1,3-oxazine (0.95 g), m.p. 180° C., is obtained.

1. customafter purification of the solid
2. customobtained by chromatography on a column (height: 30 cm; diameter: 2.5 cm) of silica (0.2-0.063 mm)
3. washeluting with a mixture of cyclohexane and ethyl acetate (80:20 by volume)
4. customcollecting 20cc fractions, fractions 1 to 5 being
5. concentrationconcentrated to dryness under reduced pressure (4 kPa) at 45° C.
6. customfollowed by recrystallization of the residue in acetonitrile (12 cc)