Model reactions for the biosynthesis of thyroxine. Part XVII. On the mechanism of the conversion of 4-hydroxy-3,5-di-iodophenylpyruvic acid into thyroxine

Abstract

4-Hydroxy-3,5-di-iodobenzoylglyoxylic acid is a potential intermediate in the nonenzymic formation of thyroxine from 3,5-di-iodotyrosine and 4-hydroxy-3,5-di-iodophenylpyruvic acid; its ethyl ester has been synthesised. The lack of reactivity of this ester towards 3,5-di-iodotyrosine indicates that the diketo-acid is not an intermediate in the formation of thyroxine.