Ethanol → Azithromycin ethanolate

Participants

Reaction Steps

Ten g of azithromycin crude was introduced into a 0.25 liter three-necked flat flanged jacketed vessel equipped with a mechanical stirrer, a condenser and thermometer and containing 30 ml of absolute ethanol at 20° C. Three ml of water at 20° C. were added and the solution was heated at a constant temperature gradient so as to reach 55° C. after 4 hours. Between 35° C. and 55° C., additional water having a total volume of 11 ml was slowly added at regular time intervals. When 55° C. was reached, the resulting suspension was maintained at this temperature for 2 hours, during which an additional 49 mL of water was added. The suspension was then cooled from 55° C. to 20° C. over 2 hours. The precipitate was filtered. After drying, 9 g of azithromycin ethanolate were obtained.

Provenance & Evidence