Process for producing erythromycin derivatives

Abstract From the Canadian patent

The hydroxyl group in position 2' of erythromycin A is acetylated, the hydroxyl group in position 4" is formylated and subjected to reaction for the formation of hemiketal; subsequently, the hydroxyl group in position 11 is oxidized and the hydroxyl group in position 12 is alkylated, followed by removal of the acetyl group in position 2' and the formyl group in position 4" to yield a compound; the compound is reacted with benzyloxycarbonyl chloride under basic conditions and, thereafter the, introduced benzyloxycarbonyl group is removed and the nitrogen atom in position 3' is subsequently alkylated followed by conversion to a fumarate in a crude crystal form, which is then recrystallized …