BE-19412A

Fredericamycin A is an antitumor antibiotic with a unique spiro-structure and strong physiol. effects.To search for new antitumor and anti-infective compounds, the fermentation products of Streptomyces griseus ATCC 49344 were analyzed.Besides fredericamycin A, two intensively colored violet pigments were also isolated from this strain; they turned out to be identical in their physicochem. properties with the formerly described fredericamycins B and C.The structure of these minor compounds was determined by extensive NMR measurements and by comparison of the physicochem. properties.Fredericamycin C is the most unstable compound, with mol. mass of m/z = 572, corresponding to C₃₁H₂₄O₁₁.Fredericamycin B shows a mol. mass of m/z = 553, indicating at least one nitrogen.The results suggested a tentative structure for fredericamycin B, which is closely related to the structure of ericamycin and BE-19412A, showing a 2-azahexaphene moiety and a very similar skeleton.