Actinomyces albus var. bruneomycini

Its structure was deduced by Rao, Biemann, and Woodward in 1963 (75). A few years later, the same compound was independently isolated by two research groups from a strain of Actinomyces albus var. bruneomycini (74,75) and from S. rufochromogenes and S. echinatus (76), being named bruneomycin and rufochromomycin, respectively. 

Streptonigrin was first isolated in 1959 in the United States from a culture of Streptomyces flocculus (/). The same compound was independently isolated in the Soviet Union a few years later from a strain of Actinomyces albus var. bruneomycini (2) and in France from S. rufochromogenes and S. echinatus (3), the antibiotic being named bruneo-mycin and rufochromomycin, respectively. The antibiotic forms dark brown crystals which are slightly soluble in water, lower alcohols, ethyl acetate or chloroform and more soluble in dioxane, pyridine, DMF or THF. Streptonigrin has UV absorption maxima in methanol at 248 nm (e 38,400) and 375—380 nm (e 17,400). It is a monobasic acid with pKa 6.2—6.4 in 1 1 dioxane water. 

---