Myocardial imaging agents: synthesis, characterization, and evaluation of (Z)- and (Z,E)-18-[82Br]bromo-5-tellura-17-octadecenoic acids.

The effects of replacement of radioiodide with radiobromide on the biological properties of a model vinyl halide substituted tellurium fatty acid have been evaluated. The use of a facile radiobromination method involving the reaction of [82Br]Br2 with vinylmercuric bromide substrates has been investigated. Unexpectedly, both the cis- and trans-vinyl bromide products are formed as confirmed by chromatographic and spectral studies. With use of this technique, (E,Z)-1-[82Br]bromo-13-iodo-1-tridecene was prepared and used as the substrate to prepare (E,Z)-18-[82Br]bromo-5-tellura-17-octadecenoic acid (13-E,Z), which was evaluated in rats. Both [82Br]-13-E,Z and [82Br]-13-Z, prepared by an established procedure using N-chorosuccinimide-Br- reaction with the trans-boronovinyl substrates, showed tissue distribution properties similar to those of (E)-18-[125I]iodo-5-tellura-17-octadecenoic acid. These results demonstrate that replacement of I with Br and also the stereochemistry about the olefinic bond do not drastically affect heart uptake and retention.