Thiouracil refers both to a specific molecule consisting of a sulfated uracil, and a family of molecules based upon that structure. The substance is a historically relevant antithyroid preparation. Astwood E.B. used it in 1943 as therapy of Graves' disease for the first time. It remains in use.
^Nagasaka, A.; Hidaka, H. (1976). "Effect of Antithyroid Agents 6-Propyl-2-Thiouracil and l-Methyl-2-Mercaptoimidazole on Human Thyroid Iodide Peroxidase". Journal of Clinical Endocrinology & Metabolism43 (1): 152–8. doi:10.1210/jcem-43-1-152. PMID947933.