Bledta II: Synthesis of a new tumor‐visualizing derivative of CO(III)‐bleomycin

A new bifunctional chelating agent, (S)‐l‐(p‐bromoacetamidobenzyl) ethylenedinitrilotetraacetic acid, has been prepared from L‐phenylalanine. Reaction of the chelating agent with the Co(III) complex of the antitumor antibiotic bleomycin‐A2DM was used to generate a new derivative of Co(III)‐bleomycin, BLEDTA II. The product can be radiolabeled quickly by binding a radioactive metal ion to the EDTA group. The in vivo distribution of 111 In‐BLEDTA II in tumor‐bearing mice was determined and found to be indistinguishable from that of the clinically useful 111 In(III)‐BLEDTA I complex (J. Med. Chem. 22: 1019 (1979)).