Erythromycylamine is a semi-synthetic analogue of erythromycin prepared by reduction of erythromycin oxime. Erythromycylamine is a potent antibiotic, however the introduction of the amino- moiety increases the compound's polarity and is disadvantageous for in vivo use. This limitation was overcome by the synthesis of dirithromycin, a Schiff base pro-drug that dissociates in vivo to erythromycylamine.