(3r,4s,5s,7r,8r,9e,11s,15r,17r)-3,8-dihydroxy-17-[(s)-hydroxy-[(3r)-2-methyl-3-[(z,2s)-pent-3-en-2-yl]oxiran-2-yl]methyl]-4-methoxy-5,7,9,11,15-pentamethyl-1-oxacyclooctadec-9-ene-2,6,12,16-tetrone