New anthracyclines, feudomycins, produced by the mutant from Streptomyces coeruleorubidus ME130-A4

Various blocked mutants were isolated from Streptomyces coeruleorubidus ME130-A4 by NTG and UV treatments. Among them, mutant strain 4N-140 produced new anthracycline feudomycins A and B having new aglycones in which the side chain at C-9 position of daunomycinone was ethyl and acetonyl, respectively. New aglycones feudomycinones C and D having methyl at C-9 and additional groups at C-10 of daunomycinone were also isolated from this strain.