α-Ethyl-3-hydroxy-2,4,6-triiodohydrocinnamic acid (iophenoxic acid ) was used as marker in “bait acceptance” studies conducted on various animal species. It was used in the direct quantitation of iophenoxic acid in porcine serum samples by a liquid chromatographic-electrospray ionization mass spectrometric technique.
A mixture of m-hydroxy-benzaldehyde, fused sodium propionate and of
butyric anhydride was stirred and refluxed at heating.
The mixture was then poured into water and acidified with hydrochloric acid.
The organic material was extracted with chloroform, the chloroform was
exaporated, and the residue stirred for one and 1.5 h with dilute potassium
hydroxide solution. Acetic acid was added to make the solution almost neutral,
but still slightly basic, the mixture was stirred with activated charcoal for
about 15 min, filtered, and the filtrate acidified to Congo red with hydrochloric
acid. A crystalline product was obtained upon cooling for several hours, and
this was collected by filtration and recrystallized from water giving α-ethyl-mhydroxycinnamic acid.
A solution of α-ethyl-m-hydroxycinnamic acid and potassium hydroxide in
water was added to 3% sodium amalgam, and the mixture was stirred while
heating on a steam bath for several hours. The mixture was then cooled, the
mercury separated, and the reaction mixture was acidified and extracted with
ether. The ether extracts were concentrated giving a residue containing α-
ethyl-β-(m-hydroxyphenyl)propionic acid.
α-Ethyl-β-(m-hydroxyphenyl)propionic acid was dissolved in acetic acid. The
solution was warmed on a steam bath, and water was added followed iodine
monochloride. The mixture was stirred and heated for several hours, and
water was then added to cause precipitation of the product. The semi-solid
precipitate was triturated with a small amount of 95% alcohol, collected by
filtration and washed with low boiling petroleum ether. Recrystallization from
dilute alcohol, using charcoal for decolorization, gave α-ethyl-β-(2,4,6-triiodo-
3-hydroxyphenyl)propionic acid.
α-Ethyl-3-hydroxy-2,4,6-triiodohydrocinnamic acid (Iophenoxic acid ) is an organic, iodine-containing compound. Iophenoxic acid is an iodinated radiocontrast agent, its clinical use has been withdrawn due to its exceptionally long half-life in the body, since it has high-affinity binding to human serum albumin (HSA). Structural basis of its interaction with HSA has been evaluated.
