110480-13-2 8,9-Didehydro-N-demethyl-9-deoxo-6-deoxy-6,9-epoxy-N-(1-methylethyl)erythromycin EM 574 EM-574 EM574 Erythromycin, 8,9-didehydro-N-demethyl-9-deoxo-6-deoxy-6,9-epoxy-N-(1-methylethyl)-