Azithromycin Impurity 60

(2S,3S,4R,7R,8S,9S,10R,11R,13R) -10- (((2S,3R,4S,6R) -4- (dimethylamino) -3-hydroxy-6-methyltetrahydro-2H-pyran-2-yl) oxy) -2- ((S) -1- (dimethylamino) ethyl) -4-ethyl-3,11-dihydroxy-8- (((2R,4R,5S,6S) -5-hydroxy-4-methoxy-4,6-dimethyltetrahydro-2H-pyran-2-yl) oxy) -3,7,9,11,13-pentamethyl-1,5-dioxacyclotetradecane-6,14-dione