反应详情

温度

220 °C

A mixture of 20.6 g (0.10 mol) of 2,4-di-tert-butylphenol and 22.6 g (0.10 mol) of 4-methallyloxymandelic acid (preparation as in Example 1) is kept at 155° C. under reduced pressure (50 mbar) for 8 hours. The reaction mixture is then heated to 220° C. under nitrogen and kept at this temperature for about 100 minutes. After cooling to about 120° C., 100 ml of acetic acid and 2 ml of methanesulfonic acid are added and the solution is refluxed for 3 hours. The reaction mixture is cooled, and the product is precipitated with 10 ml of ethanol and isolated by filtration. Recrystallisation from ethanol (100 ml)/acetic acid (8 ml) gives 8.0 g (20%) of 3-(2,2-dimethyldihydrobenzofuran-5-yl)-5,7-di-tert-butylbenzofuran-2-one, m.p. 164°-166° C. (compound (102), Table 1 ).

1. waitkept at this temperature for about 100 minutes
2. temperatureAfter cooling to about 120° C.
3. temperaturethe solution is refluxed for 3 hours
4. temperatureThe reaction mixture is cooled
5. customthe product is precipitated with 10 ml of ethanol
6. customisolated by filtration
7. customRecrystallisation from ethanol (100 ml)/acetic acid (8 ml)