The present invention is to provide a process for producing a 2-O-acetyl-4-O-formyl-8,9-anhydroerythromycin
A 6,9-hemiketal compound 4, and it provide a process for
producing an erythromycin compound which comprises reacting a formylating agent
with a 2-O-acetylerythromycin A compound 2 to obtain
2-O-acetyl-4-O-formylerythromycin A compound 3,
then, acting an acid on Compound 3 to subject to hemiketalation,
and then adding an aqueous basic solution in an aqueous solution to precipitate
Compound 4 as free crystals.
