(3aS,4R,7R,9R,10R,11R,13R,15aR)-10-((2S,3R,4S,6R)-4-Dimethylamino-3-hydroxy-6-methyl-tetrahydro-pyran-2-yloxy)-4-ethyl-11-methoxy-3a,7,9,11,13,15-hexamethyl-1-(4-phenyl-butyl)-octahydro-3,5-dioxa-1-aza-cyclopentacyclotetradecene-2,6,8,14-tetraone
2'-O-acetyl-10,11-didehydro-11-deoxy-12-O-(1H-1-imidazoylcarbonyl)-3-O-descladinosyl-3-oxo-6-O-methyl-erythromycin A