Ristomycin A aglycone, 34-O-2-(acetylamino)-2-deoxy-.beta.-D-glucopyranosyl-22,31-dichloro-7-demethyl-64-O-demethyl-19-deoxy-56-O-2-deoxy-2-(8-methyl-1-oxodecyl)amino-.beta.-D-glucopyranosyl-42-O-.alpha.-D-mannopyranosyl-