反应详情

Erythromycin A (50.0 g, 68.1 mmol) (commercially available from Abbott Laboratories) was dissolved in 600 mL of methylene chloride (CH2Cl2) at ambient temperature. Triethylamine (20 mL) and 10 mL (10.82 g, 106 mmol) of acetic anhydride were added to this solution. The reaction mixture was heated to reflux and 100 mL of CH2Cl2 was distilled from the reaction mixture to remove any traces of water. The reaction mixture was heated at reflux temperature for an additional five hours. After six hours, when the reaction was complete, according to TLC analysis, the reaction mixture was cooled to ambient temperature and transferred to a separatory funnel. The CH2Cl2 solution was washed with 300 mL of ammonium hydroxide/sodium bicarbonate solution containing 2.9% ammonia and 1.8% sodium bicarbonate, dried over anhydrous sodium sulfate and filtered. The CH2Cl2 was removed using a rotary evaporator with a water bath temperature of 30°-40° C. The residue was crystallized from 200 mL of acetonitrile (CH3CN) by first dissolving it in hot CH3CN and allowing the solution to stand overnight at ambient temperature, then cooling it to -25° C. and maintaining this temperature for 24 hours. The product was isolated as white crystals which were washed with cold (-25° C.) CH3CN and dried in a vacuum oven at 50° C. for approximately 64 hours. The 2'-O-acetylerythromycin A was obtained in 83% yield (43.91 g).

1. temperatureThe reaction mixture was heated
2. temperatureto reflux
3. distillation100 mL of CH2Cl2 was distilled from the reaction mixture
4. customto remove any traces of water
5. temperatureThe reaction mixture was heated
6. temperatureat reflux temperature for an additional five hours
7. customtransferred to a separatory funnel
8. washThe CH2Cl2 solution was washed with 300 mL of ammonium hydroxide/sodium bicarbonate solution
9. additioncontaining 2.9% ammonia and 1.8% sodium bicarbonate
10. dry with materialdried over anhydrous sodium sulfate
11. filtrationfiltered
12. customThe CH2Cl2 was removed
13. customa rotary evaporator with a water bath temperature of 30°-40° C
14. customThe residue was crystallized from 200 mL of acetonitrile (CH3CN)
15. dissolutionby first dissolving it in hot CH3CN
16. waitto stand overnight at ambient temperature
17. temperaturecooling it to -25° C.
18. temperaturemaintaining this temperature for 24 hours
19. customThe product was isolated as white crystals which
20. washwere washed with cold (-25° C.) CH3CN
21. customdried in a vacuum oven at 50° C. for approximately 64 hours