erythromycin Anhydro Erythromycin A

Erythromycin Anhydro Erythromycin A is a dehydration derivative of Erythromycin A, characterized by the loss of a water molecule from the parent macrolide lactone ring, resulting in a conjugated cyclic ketone structure. This impurity retains the 14-membered macrolactam core and glycosidic linkage to cladinose and desosamine moieties but exhibits altered hydrogen bonding capacity due to the anhydro modification. The compound arises via thermal or acidic degradation pathways during erythromycin synthesis or purification. It serves as a critical HPLC reference standard for quantifying process-related impurities in erythromycin APIs.