Dichloromethane → Erythromycin

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of erythromycin thiocyanate and other impurities (100 g) was added into dichloromethane (300 mL). Butyl acetate (or ethyl acetate) (50 mL) was added, stirred under heat to 34° C. and adjusted to pH 12 until the solution became clear. The upper aqueous phase was separated and removed to obtain a dichloromethane solution with about 15% of erythromycin A. The dichloromethane solution was cooled to 23° C., kept for 2 hours and then cooled to −5° C. in 16 hours. The crystals formed were filtered. Dichloromethane (20 mL) was used to wash the crystals and the crystals were filtered for further 5 minutes. The amount of erythromycin A in the dried erythromycin is 94.8% with a dichloromethane content of 385 ppm, a water content of 1.1% and a microbiological titre of 943 μ/mg.

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