Metabolic products of microorganisms. 225. Elloramycin, a new anthracycline-like antibiotic from Streptomyces olivaceus. Isolation, characterization, structure and biological properties.

Elloramycin (1), a new antibiotic produced by Streptomyces olivaceus strain Tü 2353, was detected by chemical screening. The dark yellow compound, molecular formula C32H36O15, is weakly active against a variety of Gram-positive bacteria, especially streptomycetes and against stem cells of L-1210 leukemia. Acidic hydrolysis of the antibiotic liberated elloramycinone (3) as aglycone and 2,3,4-tri-O-methyl-L-rhamnose, which was identified as methyl glycoside 5b. The structure of elloramycin was established by comparison of the spectra (UV, 1H NMR, 13C NMR) with those of the known tetracenomycin C (2), 3 and the fact that 2 and 3 gave the same tetramethyl ether after permethylation. Elloramycin is an anthracycline-like antibiotic, the aglycone resembles tetracenomycin C, the sugar is connected in a phenolic alpha-glycosidic linkage.