Diiodotyrosine formation, effect

Horseradish peroxidase (HRP) has also been used in an enzymatic process to create aryl-aryl bonds, especially for the synthesis of diiodotyrosine derivatives in a possibly biomimetic transformation [30, 100]. Here again, the regioselectivity of bond formation is an important issue and, depending on both the conditions and the substrate, C-C or C-O-coupling can occur. The effect of substituents ortho to the alcohol group has been studied by Sih and co-... 

Saturated a-acylamino acids are prepared by acylation of o-amino acids or, less frequently, by reduction of the corresponding unsaturated compounds. It sometimes is possible to effect both the preparation of the o cylamino acid and the formation of the azlactone by heating the amino add with a large excess of acetic anhydride. Leucine and phenylalanine give excellent yields of azlactones under these conditions. However, this method is not satisfactory with alanine, diiodotyrosine, isovaline," or a-amiiioisobutyric acid," which yield products of high molecular weight. 

M. E. Morton, I. L. Chaikoff and S. Rosenfeld. Inhibition effect of inorganic iodide on the formation in vitro of thyroxine and diiodotyrosine by surviving thyroid tissue. J. Biol. Chem. 154 381 (1944)... 

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