Azithromycin Impurity 16 Catalogue A535230 CAS 189108-61-0 M.W 590.76 M.F C29H54N2O10 Specifications FAQs (3R,4S,5S,6R,7R,9R,11S,12R,13S,14R,E)-6-(((2S,3R,4S,6R)-4-(dimethylamino)-3-hydroxy-6-methyltetrahydro-2H-pyran-2-yl)oxy)-14-ethyl-4,7,12,13-tetrahydroxy-10-(hydroxyimino)-3,5,7,9,11,13-hexamethyloxacyclotetradecan-2-one