Antithyroid activity of some 6-(alkylsulfanyl)-9H-purines

Some alkyl and aryl derivatives of 9H-purine-6-thiol were synthesized and evaluated in vitro and in vivo for potential antithyroid effects. Spectrophotometric studies demonstrated 1:1 charge transfer complexation between iodine and these compounds with quite high values of the formation constants. The blood assays of rats treated with these compounds revealed significant antithyroid activity for almost all the compounds, which was further supported by a histological study of the thyroid tissues of the animals. These compounds are expected to provide less toxic alternative of the existing medicines as the sulfa group, which is known to be a cause of toxicity of many drugs, is blocked by alkyl/aryl substituents.