6-0-METHYLERYTHROMYCIN A DERIVATIVES

摘要

This invention aims to provide novel erythromycin A derivatives having a strong antimicrobial activity against Gram-negative bacteria and having against Gram-positive bacteria also a much stronger effect than compounds so far known. This invention provides 6-O-methylerythromycin A derivatives represented by the following formula (see above formula) (wherein R1 and R2 each represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and A represents a nitrogen atom or a N->O group) and their pharmaceutically acceptable salts.