(2R)-2-{(2R,5S,6R)-6-[(2S,3S,4S,6R)-6-{(2S,5S,7R,9S,10S,12R,15R)-2-[(2R,5R,6S)-5-Ethyl-5-hydroxy-6-methyltetrahydro-2H-pyran-2-yl]-15-hydroxy-2,10,12-trimethyl-1,6,8-trioxadispiro[4.1.5.3]pentadec-13-en-9-yl}-3-hydroxy-4-methyl-5-oxooctan-2-yl]-5-methyltetrahydro-2H-pyran-2-yl}butanoic acid