Erythromycin → Erythromycin A enol ether

Participants

Reaction Steps

Synthesis of EM701 was disclosed in detail in WO 02/14338 A1. A glacial acetic acid solution of erythromycin was stirred at room temperature for 2 hours, and aqueous sodium hydrogencarbonate solution was slowly added and neutralized. The reaction mixture was extracted with chloroform. The organic layer was dehydrated by adding anhydrous sodium sulfate, which was removed off by filtration to obtain crude product. The crude product was purified by silica gel column chromatography with chloroform-methanol-aqueous ammonia (10:0.5:0.01→10:1:0.05) to obtain erythromycin A enol ether. Potassium carbonate was added to methanol solution of erythromycin A enol ether and refluxed for 2 hours. After solvent was removed, the residue was dissolved in aqueous sodium hydrogencarbonate and the mixture was extracted with chloroform. The extract was dehydrated with sodium sulfate, filtered and distilled off. The obtained crude product was purified by silica gel column chromatography with chloroform-methanol-aqueous ammonia (10:0.5:0.01→10:1:0.05) to obtain EM701 (white powder).

Provenance & Evidence