21′,24′-Dihydroxy-4-(methoxyimino)-5,11′,13′,22′-tetramethyl-6-(4-methyl-2-penten-2-yl)-3,4,5,6-tetrahydro-2′H-spiro[pyran-2,6′-[3,7,19]trioxatetracyclo[15.6.1.1~4,8~.0~20,24~]pentacosa[10,14,16,22]te traen]-2′-one