反应详情

7.18 g (189 mmol) of sodium borohydride was added to a solution of 10.76 g (65.5 mmol) of 4-methoxy-3H-benzofuran-2-one in 150 mL of ethyleneglycol dimethyl ether and stirred. While cooled on an ice-water bath, a solution of 5.25 mL (9.66 g, 94.5 mmol) of concentrated sulfuric acid in 21 mL of ethyleneglycol dimethyl ether was added dropwise thereto over 30 minutes. This mixture was heated and stirred on a 50° C. water bath for 49 minutes and then, while being stirred on an ice-water bath, 32 mL (25.3 g, 790 mmol) of methanol was added dropwise thereto for 6 minutes. This mixture was heated and stirred on a 50° C. water bath for 53 minutes, allowed to stand at room temperature overnight, 300 mL of isopropyl acetate and 200 mL of water were added therein and then the mixture was stirred for 5 minutes, transferred into a separatory funnel and settled. The aqueous layer was separated and discarded and after the organic layer was washed with 100 mL of water twice, the solvent was evaporated. The residue was crystallized from ethyl acetate-hexane and the obtained crystals were dried in vacuo at 30° C. and 3.12 g of the title compound was obtained.

1. temperatureWhile cooled on an ice-water bath
2. temperatureThis mixture was heated
3. stirringstirred on a 50° C. water bath for 49 minutes
4. stirringwhile being stirred on an ice-water bath
5. waitfor 6 minutes
6. temperatureThis mixture was heated
7. stirringstirred on a 50° C. water bath for 53 minutes
8. waitto stand at room temperature overnight
9. stirringthe mixture was stirred for 5 minutes
10. customtransferred into a separatory funnel
11. customThe aqueous layer was separated
12. washafter the organic layer was washed with 100 mL of water twice
13. customthe solvent was evaporated
14. customThe residue was crystallized from ethyl acetate-hexane
15. customthe obtained crystals were dried in vacuo at 30° C.