α-Methylene and glycidic acid analogs of IPPA as potential myocardial imaging agents

Using organozinc cross-coupling reactions, two radiolabeled analogs of 15-( p-iodophenyl) pentadecanoic acid (IPPA) have been designed and synthesized as potential scintigraphic imaging agents for the heart. Both 15-(4-iodophenyl)-tridecylglycidic acid and 15-(4-iodophenyl)-2-methylene pentadecanoic acid were synthesized and radioiodinated. In tissue biodistribution studies in rats, only the α-methylene derivative of IPPA displayed a consistently higher heart to blood ratio and a substantially lower degree of thyroid accumulation than did IPPA alone. With respect to a scintigraphic imaging efficacy, the α-methylene analog of IPPA and IPPA itself showed essentially equivalent cardiac imaging profiles in rabbits, with a slight extension in imaging time for the α-methylene analog of IPPA.