反应详情

7-Hydroxy-2,3-dihydro-2,2-dimethylbenzofurane is dissolved in 100 ml pyridine. 0.5 mol benzoyl chloride is added dropwise at 0° C. within 4 h. Subsequently it is stirred for 10 h at room temperature. It is poured onto 200 ml ice water and aspirated. The residue is washed with 500 ml 2 M hydrochloric acid and then with 1000 ml water and dried in air. A solution of 0.906 mol chromium trioxide in 370 ml glacial acetic acid is added dropwise to a solution of this crude product (0.45 mol) in 600 ml glacial acetic acid in such a way that the temperature of the mixture does not exceed 20° C. After the dropwise addition is completed it is stirred for a further 1 hour at 40° C. and subsequently poured onto 2 l water. It is suction filtered. The residue is washed with 1 l water and recrystallized from ethanol/water 3:1. The benzoyl compound is fed into 400 ml 10% ethanolic potassium hydroxide solution and the mixture is heated for 1 hour to 70° C. It is admixed with 3 l water and suction filtered. The residue is recrystallized from 2 l water.

1. washThe residue is washed with 500 ml 2 M hydrochloric acid
2. dry with materialwith 1000 ml water and dried in air
3. customdoes not exceed 20° C
4. additionAfter the dropwise addition
5. stirringis stirred for a further 1 hour at 40° C.
6. filtrationfiltered
7. washThe residue is washed with 1 l water
8. customrecrystallized from ethanol/water 3:1
9. temperaturethe mixture is heated for 1 hour to 70° C
10. filtrationfiltered
11. customThe residue is recrystallized from 2 l water