Rapamycin Impurity 1

Chemical Name: (2S)-1-(2-((2R,3R,6S)-2-hydroxy-6-((2S,3E,5E,7E,11R,13R,14R,15E,17R,19E,21R)-14-hydroxy-22-((1S,3R)-4-(2-hydroxyethoxy)-3-methoxycyclohexyl)-2,13-dimethoxy-3,9,11,15,17,21-hexamethyl-12,18-dioxodocosa-3,5,7,15,19-pentaen-1-yl)-3-methyltetrahydro-2H-pyran-2-yl)-2-oxoacetyl)piperidine-2-carboxylic acid