Synonyms: Hygrolidin,21-O-de(3-carboxy-1-oxo-2-propenyl)-; Antibiotic 1166E;Oxacyclohexadeca-3,5,11,13-tetraen-2-one,16-[3-(6-ethyltetrahydro-2,4-dihydroxy-5-methyl-2H-pyran-2-yl)-2-hydroxy-1-methylbutyl]-8-hydroxy-15-methoxy-3,5,7,9,11-pentamethyl-,[7R-[3E,5E,7R*,8S*,9S*,11E,13E,15S*,16R*[1S*,2R*,3S*(2R*,4R*,5R*,6R*)]]]-