Thyroid Receptor Ligands. 3. Design and Synthesis of 3,5-Dihalo-4-alkoxyphenylalkanoic Acids as Indirect Antagonists of the Thyroid Hormone Receptor

Based on the recently described concept of "indirect antagonism" of nuclear receptors, a series of thyroid hormone receptor (TR) antagonists were prepared, in which the outer ring of a thyromimetic was replaced with alkyl chains of variable length and branch. The results of a binding assay for the human TR and reporter cell assay revealed, within this series, a positive correlation between increasing bulk of the alkyl group and affinity to TRs. Compared with already reported TR antagonists, their affinities are within the same range, thus potentially representing a useful approach to novel and high affinity TR-antagonists.