4-(dimethylamino)-2-({(3R,4S,6R,7R,9R,11R,12R,13S,14R)-14-ethyl-7,12,13-trihydroxy-4-[(5-hydroxy-4-methoxy-4,6-dimethyltetrahydro-2H-pyran-2-yl)oxy]-3,5,7,9,11,13-hexamethyl-2,10-dioxooxacyclotetradecan-6-yl}oxy)-6-methyltetrahydro-2H-pyran-3-yl ethyl but