反应详情

Ammonia (28% aq. 20 mL) was added to a solution of 3-ethoxy-2-methyl-4H-pyran-4-one (8.5 g, 55 mmol, obtained from Example 4(a)) in ethanol (20 mL) and the mixture was stirred under reflux for 24 h. The reaction mixture was cooled to r.t. and the solution was evaporated in vacuo. The pH was adjusted to pH 1 with 2M HCl, and the aqueous phase was extracted with ethyl acetate. The pH of the water phase was then adjusted to pH 10 with 2M sodium hydroxide. The aqueous phase was extracted with ethyl acetate (3×100 mL) and then saturated with NaCl (s) and extracted with CHCl3. The organic phase was dried (Na2SO4) and evaporated to give the title product (8.0 g, 95%). The crude product was used in the next step without further purification.

1. temperatureunder reflux for 24 h
2. customthe solution was evaporated in vacuo
3. extractionthe aqueous phase was extracted with ethyl acetate
4. extractionThe aqueous phase was extracted with ethyl acetate (3×100 mL)
5. extractionsaturated with NaCl (s) and extracted with CHCl3
6. dry with materialThe organic phase was dried (Na2SO4)
7. customevaporated