Competitive antagonists of thyroxine and structurally related compounds.

Woolley (1) has prepared a number of ethers of N-acetyl-3,5-diiodotyrosine and found them to interfere with various effects of thyroxine on amphibian larvae. Some of Woolley’s observations were confirmed and extended by Winder and Frieden (2) and by Williams et al. (3). It is the purpose of this report to investigate the competitive nature of several thyroxine inhibitors and to determine the structural requirements for and the specificity of the inhibition of thyroxine and its active analogues,