Effect of tellurium position on the myocardial uptake of radioiodinated 18-iodotellura-17-octadecenoic acid analogs

Publisher Website
Google Scholar
Abstract
The effect of Te position on myocardial specificity and retention of fatty acids in which radioiodide is stabilized as a trans-(E)-vinyl iodide was evaluated in rats. Five analogs of 18-iodo-17-octadecenoic acid (ICH.dbd.CH-R-Te-R''-COOH) with Te at positions 5, 7, 9, 11 and 13 were prepared by coupling of a trans-diiodoalkene (ICH.dbd.CH-R-I) with the requisite sodium [(alkoxycarbonyl)alkyl]telluride substrate (NaTe-R''-COOR"; R" = Me [methyl] or ET [ethyl]), followed by basic hydrolysis. By varying R and R'', a series of analogs with a chain length of 18 C atoms was prepared. The telluride substrates were generated in situ by NaBH4 reduction of the corresponding ditellurides, and the diiodoalkenes were prepared by NaI chloramine-T treatment of the corresponding vinylboronic acids [(HO)2BCH.dbd.CH-R-I)]. The vinylboronic acids were prepared by treatment of the terminal acetylenes (HC.dbd.C-R-I), synthesized from commercially available materials with catecholborane. All new compounds were analyzed by TLC, NMR, MS [mass spectrometry] and elemental analyses. The 125I analogs [(E)-125ICH.dbd.CH-R-Te-R''-COOH] were prepared in the same manner and evaluated in rats (4 per group). Heart uptake and retention were dependent upon the Te position. The analog with Te at position 5 showed that most pronounced (5-min values) heart uptake (3.7-4.1 dose/g), myocardial rention, and heart/blood ratios (37:1) and is a candidate for radiolabeling with 125I and further evaluation as a myocardial imaging agent.