(1'S,3'E,5'S,6'S,7'S,8'R,9'R,10'R,11'S,12'S,13'E,15'Z)-7',9',11',22'-tetrahydroxy-5'-methoxy-1',6',8',10',12',16',23'-heptamethylspiro[1,3-dioxolane-2,29'-18-aza-2,25-dioxatetracyclo[17.6.5.021,28.024,27]triaconta-3,13,15,19(30),21(22),23,27(28)-heptaene]-4,17',20',26'-tetraone