80890-47-7 Antibiotic X 4357 B Concanamycin A Oxacyclooctadeca-3,5,13,15-tetraen-2-one, 18-((1S,2R,3S)-3-((2R,4R,5S,6R)-4-((4-O-(aminocarbonyl)-2,6-dideoxy-beta-D-arbino-hexopyranosyl)oxy)tetrahydro-2-hydroxy-5-methyl-6-(1E)-1-propenyl-2H-pyran-2-yl)-2-hydroxy-1-methylbutyl)-9-ethyl-8,10-dihydroxy-3,17-dimethoxy-5,7,11,13-tetramethyl-, (3Z,5E,7R,8R,9S,10S,11R,13E,15E,17S,18R)- X 4357 B