Potential anticancer agents--nitroxyl derivatives of Rubomycin. 
Two new of the spin-labeled analogues of Rubomycin were studied.  It was shown that spin-labeled derivatives were less toxic than the parent compound and had a broad-spectrum antitumor activity.  Spin-labeled derivative was clearly less cardiotoxic in the rat model than Rubomycin (Daunorubomycin).