Patent ID: 6906039

Claim:
A process for preparing an erythromycin compound which comprises subjecting 2′-O-acetyl-4″-O-formyl-11-oxo-8,9-anhydroerythromycin A 6,9-hemiketal compound 1 represented by the formula (1): wherein R 1 and R 2 each independently represent a lower alkyl group, to alkylation, wherein Compound 1 is reacted with an alkylating agent in the presence of a base in a mixed solvent of 0.18 to 1.05 equivalent of water based on the amount of Compound 1 and an organic solvent to give 2′-O-acetyl-4″-O-formyl-11-oxo-12-alkoxy-8,9-anhydroerythromycin A 6,9-hemiketal compound 3 represented by the formula (3): wherein R represents a lower alkyl group, and R 1 and R 2 have the same meanings as defined above.