Acetic acid, 2,2-(1S,3S,7R,8E,11R,15S,17R,21R,23R,25S)-25-(acetyloxy)-1,11,21-trihydroxy-17-(1R)-1-hydroxyethyl-10,10,26,26-tetramethyl-19-oxo-18,27,28,29-tetraoxatetracyclo21.3.1.13,7.111,15nonacos-8-ene-5,13-diylidenebis-, dimethyl ester, (25Z,213E)-