反应详情

Twenty five grams (25 g) of 2-hydroxyacetophenon, 10.7 g of acetone, and 5.5 g of pyrrolidine were added to 50 ml of toluene, and heated and refluxed. Twenty hours later, the temperature was returned to ambient temperature and the solvent was distilled off under reduced pressure, to which was added 100 ml of 1N hydrogen chloride. The extraction was carried out with 50 ml×3 of chloroform, followed by washing in water, drying over anhydrous magnesium sulfate, filtering off and condensation of the filtered solution. The residue was purified on a silica gel column the fraction containing the purified product were mixed together and the solvent therein was distilled off under reduced pressure to obtain 7 g of 3,4-dihydro-2,2-dimethyl-2H-benzo[b]pyran-4-one.

1. temperatureheated
2. temperaturerefluxed
3. customTwenty hours
4. customwas returned to ambient temperature
5. distillationthe solvent was distilled off under reduced pressure, to which
6. additionwas added 100 ml of 1N hydrogen chloride
7. extractionThe extraction
8. washby washing in water
9. dry with materialdrying over anhydrous magnesium sulfate
10. filtrationfiltering off
11. customcondensation of the filtered solution
12. customThe residue was purified on a silica gel column the fraction
13. additioncontaining the purified product
14. additionwere mixed together
15. distillationthe solvent therein was distilled off under reduced pressure