反应详情

温度

5 °C

Dissolve 300 g of beclomethasone dipropionate in 2 liters of methylene chloride at reflux. Treat with 15 g activated charcoal for 15 minutes at reflux and filter while hot. Concentrate the filtered solution to a volume of 900 ml and while maintaining reflux add slowly 900 ml of n-hexane. Cool to 0-10° C. Filter the resultant precipitate and wash with n-hexane. Dry the precipitate in air at <50° C. until constant weight to afford beclomethasone dipropionate-n-hexane solvate having an [α]/D25 =+85.5±2° in dioxane and an ε1% (extinction coefficient) in 1% solution=275±10 at 239 mu. Analysis by gas chromatography shows an n-hexane content of 4.6%. The beclomethasone dipropionate content (determined by ultraviolet assay) is 94.5%.

1. temperatureat reflux
2. additionTreat with 15 g
3. customfor 15 minutes
4. temperatureat reflux
5. filtrationfilter while hot
6. concentrationConcentrate the filtered solution to a volume of 900 ml
7. temperaturewhile maintaining
8. temperaturereflux
9. additionadd slowly 900 ml of n-hexane
10. filtrationFilter the resultant precipitate
11. washwash with n-hexane
12. customDry the precipitate in air at <50° C. until constant weight