The biological action of substances related to thyroxine. 2. Further derivatives of 3:5-diiodo-4-hydroxybenzoic acid

Abstract

A series of fifteen 3,5-diiodo-4-hydroxybenzoic acids and their esters was tested for antithyroxine activity by the O2 consumption method in mice, but all were markedly inferior to n-butyl 3,5-diiodo-4-hydroxybenzoate. Four branched-chain alkyl esters of 3,5-diiodo-4-hydroxybenzoic acid were much less active than the straight-chain esters. 3,5-diiodo-4-methoxy-benzonitrile exerted slight antithyroxine activity, but 3,5-diiodo-4-n-propoxybenzonitrile and the corresponding benzamide were inactive.