反应详情

A mixture of 66 g of 3-cyclohexyl-7-methoxy-3,4-dihydro-benzo[e][1,3]oxazin-2-one and 200 g of pyridinium HCl are heated without solvent on a metal bath to 220° for 45 minutes whilst stirring. Evolving HCl gas is sucked off. The mixture obtained is cooled to RT, the melt obtained is dissolved in H2O and ethyl acetate and two phases obtained are separated. The aqueous layer obtained is extracted with ethyl acetate and washed with 1N HCl, dried and concentrated in vacuo. The residue obtained is filtered over silica gel and the filtration residue obtained is concentrated. 3-Cyclohexyl-7-hydroxy-3,4-dihydro-benzo[e][1,3]oxazin-2-one is obtained in crystalline form. m.p. 193-196°.

1. temperatureare heated without solvent on a metal bath to 220° for 45 minutes
2. customThe mixture obtained
3. customthe melt obtained
4. customare separated
5. customThe aqueous layer obtained
6. extractionis extracted with ethyl acetate
7. washwashed with 1N HCl
8. customdried
9. concentrationconcentrated in vacuo
10. customThe residue obtained
11. filtrationis filtered over silica gel
12. customthe filtration residue obtained
13. concentrationis concentrated