反应详情

3.80 g (10.0 mmol) of 3-(4-allyloxyphenyl)-5,7-di-tert-butyl-benzofuran-2-one are kept under nitrogen for about 4 hours at 220° C. After cooling, 10 ml of acetic acid and 0.3 ml of methanesulfonic acid are added and the reaction mixture is refluxed for 7 hours. After dilution with 100 ml of water, the product is extracted with dichloromethane. The organic phases are washed with water, combined, dried over sodium sulfate and concentrated on a vacuum rotary evaporator. Chromatography of the residue on silica gel with the eluant system dichloromethane/hexane=1:2 and crystallisation of the pure fractions from ligroin gives 1.07 g (28%)of 5,7-di-tert-butyl-3-(2-methyl-dihydrobenzofuran-5-yl)benzofuran-2-one, m.p. 136°-152° C. as a mixture of diastereoisomers (compound (101), Table 1).

1. temperatureAfter cooling
2. temperaturethe reaction mixture is refluxed for 7 hours
3. extractionAfter dilution with 100 ml of water, the product is extracted with dichloromethane
4. washThe organic phases are washed with water
5. dry with materialdried over sodium sulfate
6. concentrationconcentrated on a vacuum rotary evaporator
7. customChromatography of the residue on silica gel with the eluant system dichloromethane/hexane=1:2 and crystallisation of the pure fractions from ligroin