11,12-O-isopropylidene-5,6-O-<1-(4-methoxyphenyl)ethylidene>dihydroerythronolide A

(2S,3R,4S,5R,6R,8R,9S,10S,11R,12R,13R)-9,13-dihydroxy-1,3:11,12-bis(isopropylidenedioxy)-5,6-<1-(4-methoxyphenyl)-ethylenedioxy>-2,4,6,8,10,12-hexamethylpentadecane