Structures of the bioxalomycins and their relationship to naphthyridinomycin

Bioxalomycins α1, α2 β1, and β2 are novel compounds with potent antimicrobial and antitumor activity isolated from fermentation broths of Streptomyces viridostaticus. These structures are closely related to that of naphthyridinomycin and call into question the published structure of the naturally occurring form of that antitumor antibiotic