Definition and Usage Areas of Thiourea
Thiourea, an organic compound similar to urea, is formed by replacing the oxygen atom of urea with a sulfur atom. Sulfocarbamide is also known as sulfonylurea or thiocarbamide. Its chemical formula is CS(NH2)2. It is a solid that melts at 172 °C. It is soluble in water and alcohol.
- Although its commercial importance is not much, it is mainly used in photography, the production of thermosetting resins, insecticides, weaving, some dyes, and drugs. It is a toxic substance.
- Thiourea is a reagent capable of complexing with gold and silver. This urea can dissolve metallic gold and silver with a suitable oxidizer.
- Other industrial uses of thiourea include the manufacture of flame retardant resins and curing accelerators.
- Thiourea is used as an auxiliary agent on diazo paper, photosensitive copy paper, and almost all other copy paper.
- It is also used for photographic prints in tint silver gelatin.
- Thiourea, Clifton-Phillips, and Beaver are used in bright and semi-gloss electroplating processes.
- It is also used in a solution containing tin(II) chloride as an electrolysis tin plating solution for copper printed circuit boards.
Applications for Thiourea
Reagent for organic synthesis as a reagent for organic synthesis. Thiourea is a photographic fixative and is used in the manufacture of resins. It acts as a catalyst for asymmetric reactions. It plays an essential role as a catalyst for the highly enantio- and diastereoselective additions reaction of oxindoles to nitroolefins. It is also useful to improve the productivity of mung beans.
Reagent for the conversion of alkyl halides to thiols by base hydrolysis of the isothiouronium salts; see also N-Acetylthiourea, B21198. Cleavage of isothiouronium salts with base and alkylation of the resulting thiolate has been used as a convenient synthesis of unsymmetrical sulfides: Synth. Commun., 14, 209 (1984).
Epoxides are converted to episulfides: J. Org. Chem., 26, 3467 (1961). The 2,3-epoxy alcohols resulting from the Sharpless enantioselective epoxidation can be converted to the corresponding episulfides with retention at both centers, using Ti(O-i-Pr)4 as mediator: J. Org. Chem., 53, 4114 (1988).
Widely used in heterocyclic syntheses, e.g. of thiazoles and pyrimidines.
Has been used in a convenient synthesis of isothiocyanates from oximes via the nitrile oxide: Tetrahedron Lett., 34, 8283 (1993); see also Benzaldoxime, A12053:
Bui, T.; Syed, S.; Barbas, C. F. Thiourea-Catalyzed Highly Enantio- and Diastereoselective Additions of Oxindoles to Nitroolefins: Application to the Formal Synthesis of (+) -Physostigmine. J. Am. Chem. Soc. 2009, 131 (25), 8758-8759.
Takemoto, Y. Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions. Chem. Pharm. Bull. 2010, 58 (5), 593-601.