反应详情

11 g of the compound (123) obtained in Comparative Example 5 was added to 200 ml of concentrated hydrochloric acid, and the solution heated at reflux for 2.5 hours. After air-cooling, the solution was extracted with 500 ml of ethyl acetate four times, and the extract was washed with aqueous 10% sodium hydrogen carbonate solution. After drying over magnesium sulfate, the solvent was removed by distillation. The residue was crystallized with n-hexane, and the crystals were filtered to obtain 8.33 g of the subject compound (124) in a 97% yield.

1. temperaturethe solution heated
2. temperatureat reflux for 2.5 hours
3. temperatureAfter air-cooling
4. extractionthe solution was extracted with 500 ml of ethyl acetate four times
5. washthe extract was washed with aqueous 10% sodium hydrogen carbonate solution
6. dry with materialAfter drying over magnesium sulfate
7. customthe solvent was removed by distillation
8. customThe residue was crystallized with n-hexane
9. filtrationthe crystals were filtered