反应详情

A solution of methyl 2-(2-ethyl-3-methyl-4-oxo-4H-1-benzopyran-6-yl)propionate (1 g) in ethanol (120 mls), and sodium bicarbonate (1 g) in water (30 mls) was refluxed for 20 hours. The ethanol was removed on a `Rotavapor` and the residue was washed with ether (3×50 mls). After acidification with dilute hydrochloric acid, the aqueous phase was extracted with ethyl acetate (3×50 mls), which was washed with brine solution (3×30 mls), dried over anhydrous magnesium sulphate and evaporated to yield an off-white solid. This was recrystallised from ethyl acetate to yield the product as a pale yellow solid (0.4 g; 42%), mp 196°-198° C.

1. customThe ethanol was removed on a `Rotavapor` and the residue
2. washwas washed with ether (3×50 mls)
3. extractionAfter acidification with dilute hydrochloric acid, the aqueous phase was extracted with ethyl acetate (3×50 mls), which
4. washwas washed with brine solution (3×30 mls)
5. dry with materialdried over anhydrous magnesium sulphate
6. customevaporated
7. customto yield an off-white solid
8. customThis was recrystallised from ethyl acetate