Effect of tellurium position on the myocardial uptake of radioiodinated 18-iodotellura-17-octadecenoic acid analogues.
The effect of tellurium (Te) position on myocardial specificity and retention of fatty acids in which radioiodide is stabilized as a trans-(E)-vinyl iodide has been evaluated in rats. Five analogues of 18-iodo-17-octadecenoic acid (ICH = CH-R-Te-R'-COOH) with Te at positions 5, 7, 9, 11, and 13 were prepared by coupling of a trans-diiodoalkene (ICH = CH-R-I) with the requisite sodium [(alkoxycarbonyl)alkyl]telluride substrate (NaTe-R'-COOR"; R" = Me or Et), followed by basic hydrolysis. By varying R and R', a series of analogues with a chain length of 18 carbon atoms was prepared. The telluride substrates were generated in situ by NaBH4 reduction of the corresponding ditellurides, and the diiodoalkenes were prepared by sodium iodide-chloramine-T treatment of the corresponding vinylboronic acids [(HO)2BCH = CH-R-I)]. The vinylboronic acids were prepared by treatment of the terminal acetylenes (HC identical to C-R-I), synthesized from commercially available materials, with catecholborane. All new compounds were analyzed by TLC, NMR, MS, and elemental analyses. The 125I analogues [(E)-125ICH = CH-R-Te-R'-COOH] were prepared in the same manner and evaluated in rats (four per group). Heart uptake and retention were dependent upon the Te position. The analogue with Te at position 5 showed the most pronounced (5-min values) heart uptake (3.7-4.1 dose/g), myocardial retention, and heart/blood ratios (37:1) and is a candidate for radiolabeling with 123I and further evaluation as a myocardial imaging agent.
D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D005260:Female; D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D009829:Oleic Acids / Q000138:chemical synthesis* / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013329:Structure-Activity Relationship; D013691:Tellurium / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism; D014018:Tissue Distribution
D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; D009829:Oleic Acids; D013691:Tellurium