Thioureas are building blocks to pyrimidine derivatives. Thus thioureas condense with β-dicarbonyl compounds. The amino group on the thiourea initially condenses with a carbonyl, followed by cyclization and tautomerization. Desulfurization delivers the pyrimidine.
Similarly, aminothiazoles can be synthesized by the reaction of α-haloketones and thiourea.
The pharmaceuticals thiobarbituric acid and sulfathiazole are prepared using thiourea. 4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole is prepared by the reaction of thiourea and hydrazine.