Synonyms: Avoparcina, 49-chloro-7-O-de-a-D-mannopyranosyl-2C-O-methyl-;22H-8,11:18,21-Dietheno-23,36-(iminomethano)-13,16:31,35-dimetheno-1H,16H-[1,6,9]oxadiazacyclohexadecino[4,5-m][10,2,16]benzoxadiazacyclotetracosine,avoparcin a deriv.; Helvecardin B;22H-8,11:18,21-Dietheno-23,36-(iminomethano)-13,16:31,35-dimetheno-1H,16H-[1,6,9]oxadiazacyclohexadecino[4,5-m][10,2,16]benzoxadiazacyclotetracosine-26-carboxylicacid, 44-[[2-O-(3-amino-2,3,6-trideoxy-a-L-ribo-hexopyranosyl)-b-D-glucopyranosyl]oxy]-22-[(3-amino-2,3,6-trideoxy-a-L-ribo-hexopyranosyl)oxy]-19-chloro-3-(3-chloro-4-hydroxyphenyl)-6-[[(2R)-[4-[(6-deoxy-2-O-methyl-a-L-mannopyranosyl)oxy]phenyl](methylamino)acetyl]amino]-2,3,4,5,6,7,23,24,25,26,36,37,38,38a-tetradecahydro-7,28,30,32-tetrahydroxy-2,