Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Thiourea: Difference between pages

{{Short description|1=Organosulfur compound (S=C(NH2)2)}}

{{see also|Thioureas}}

|verifiedrevid = 477863582

|ImageFile1 = Thioharnstoff.svg

|ImageFile2 = Thiourea-3D-vdW.png

|ImageCaption2 = {{legend|black|[[Carbon]], C}}{{legend|white|[[Hydrogen]], H}}{{legend|blue|[[Nitrogen]], N}}{{legend|yellow|[[Sulfur]], S}}

|PIN = Thiourea<ref name=iupac2013>{{cite book|first1=Henri A.|last1=Favre|first2=Warren H.|last2=Powell|title=Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book)|url=https://books.google.com/books?id=4USgAgAAQBAJ|publisher=[[Royal Society of Chemistry]]|date=2014|location=Cambridge|pages=98, 864|doi=10.1039/9781849733069|oclc=1077224056|isbn=9780854041824}}</ref>

|OtherNames = Thiocarbamide

|Section1={{Chembox Identifiers

|CASNo = 62-56-6

|CASNo_Ref = {{cascite|correct|CAS}}

|ChEBI_Ref = {{ebicite|correct|EBI}}

|ChEBI = 36946

|PubChem = 2723790

|ChEMBL_Ref = {{ebicite|correct|EBI}}

|ChEMBL = 260876

|UNII_Ref = {{fdacite|correct|FDA}}

|UNII = GYV9AM2QAG

|SMILES = C(=S)(N)N

|UNNumber = 2811

|RTECS = YU2800000

|KEGG_Ref = {{keggcite|correct|kegg}}

|KEGG = C14415

|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

|ChemSpiderID = 2005981

|InChI = 1/CH4N2S/c2-1(3)4/h(H4,2,3,4)

|InChIKey = UMGDCJDMYOKAJW-UHFFFAOYAJ

|StdInChI_Ref = {{stdinchicite|correct|chemspider}}

|StdInChI = 1S/CH4N2S/c2-1(3)4/h(H4,2,3,4)

|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

|StdInChIKey = UMGDCJDMYOKAJW-UHFFFAOYSA-N

|Beilstein = 605327

|Gmelin = 1604

|Section2={{Chembox Properties

|Formula = {{chem2|SC(NH2)2}}

|C=1|H=4|N=2|S=1

|Appearance = white solid

|Density = 1.405 g/mL

|MeltingPtC= 182

|Solubility = 142 g/L (25 °C)

|MagSus = {{val|-4.24e-5}} cm³/mol

}}

|Section7={{Chembox Hazards

| GHSPictograms = {{GHS07}}{{GHS08}}{{GHS09}}

| GHSSignalWord = Warning

| HPhrases = {{H-phrases|302|351|361|411}}

| PPhrases = {{P-phrases|201|202|264|270|273|281|301+312|308+313|330|391|405|501}}

|NFPA-H = 3

|NFPA-F = 1

|NFPA-R = 0

}}

|Section8={{Chembox Related

| OtherCompounds = [[Urea]]<br>[[Selenourea]]

}}

}}

'''Thiourea''' ({{IPAc-en|ˌ|θ|aɪ|.|oʊ|j|ʊəˈr|iː|.|ə|,_|-|ˈ|jʊər|i|-}}){{refn|{{cite encyclopedia |url=http://www.lexico.com/definition/thiourea |archive-url=https://web.archive.org/web/20200322184329/https://www.lexico.com/definition/thiourea |url-status=dead |archive-date=2020-03-22 |title=thiourea |dictionary=[[Lexico]] UK English Dictionary |publisher=[[Oxford University Press]]}}}}{{refn|{{cite Merriam-Webster|thiourea|access-date=2016-01-21}}}}{{refn|{{cite Dictionary.com|thiourea}}}} is an [[organosulfur compound]] with the [[chemical formula|formula]] {{chem2|SC(NH2)2}} and the [[Chemical structure|structure]] {{chem2|H2N\sC(\dS)\sNH2}}. It is structurally similar to [[urea]] ({{chem2|H2N\sC(\dO)\sNH2}}), except that the [[oxygen]] atom is replaced by a [[sulfur]] atom (as implied by the ''[[thio-]]'' prefix); however, the properties of urea and thiourea differ significantly. Thiourea is a [[reagent]] in [[organic synthesis]]. [[Thioureas]] are a broad class of compounds with the general structure {{chem2|R2N\sC(\dS)\sNR2}}.

==Structure and bonding==

Thiourea is a planar molecule. The C=S bond distance is 1.71 Å. The C-N distances average 1.33 Å.<ref>{{cite journal|title=A Simple Refinement of Density Distributions of Bonding Electrons. IX. Bond Electron Density Distribution in Thiourea, CS(NH₂)₂, at 123K|author=D. Mullen |author2=E. Hellner|journal=Acta Crystallogr.|year=1978|volume=B34|issue=9 |pages=2789–2794|doi=10.1107/S0567740878009243|doi-access=|bibcode=1978AcCrB..34.2789M }}</ref> The weakening of the C-S bond by C-N pi-bonding is indicated by the short C=S bond in [[thiobenzophenone]], which is 1.63 Å.

Thiourea occurs in two [[tautomer]]ic forms, of which the [[thioketone|thione]] form predominates in aqueous solutions. The [[equilibrium constant]] has been calculated as ''K''_eq is {{val|1.04e-3}}.<ref>{{cite journal|last1=Allegretti|first1=P.E|last2=Castro|first2=E.A|last3=Furlong|first3=J.J.P|title=Tautomeric equilibrium of amides and related compounds: theoretical and spectral evidences|journal=Journal of Molecular Structure: THEOCHEM|date=March 2000|volume=499|issue=1–3|pages=121–126|doi=10.1016/S0166-1280(99)00294-8}}</ref> The [[thiol]] form, which is also known as an isothiourea, can be encountered in substituted compounds such as [[isothiouronium]] salts.

:[[File:Thiourea tautomers.png|300px]]

==Production==

The global annual production of thiourea is around 10,000&nbsp;tonnes. About 40% is produced in Germany, another 40% in China, and 20% in Japan. Thiourea can be produced from [[ammonium thiocyanate]], but more commonly it is manufactured by the reaction of [[hydrogen sulfide]] with [[calcium cyanamide]] in the presence of [[carbon dioxide]].<ref name=Ullmann/>

:{{chem2|CaCN2 + 3 H2S → Ca(SH)2 + (NH2)2CS}}

:{{chem2|2 CaCN2 + Ca(SH)2 + 6 H2O → 2 (NH2)2CS + 3 Ca(OH)2}}

:{{chem2|Ca(OH)2 + CO2 → CaCO3 + H2O}}

==Applications==

===Thiox precursor===

Thiourea ''per se'' has few applications. It is mainly consumed as a precursor to [[thiourea dioxide]], which is a common reducing agent in textile processing.<ref name="Ullmann">{{cite encyclopedia|first1=Bernd|last1=Mertschenk|first2=Ferdinand|last2=Beck|first3=Wolfgang|last3=Bauer|title=Thiourea and Thiourea Derivatives|encyclopedia=[[Ullmann's Encyclopedia of Industrial Chemistry]]|year=2002|publisher=Wiley-VCH|doi=10.1002/14356007.a26_803|isbn=3527306730}}</ref>

===Fertilizers===

Recently thiourea has been investigated for its multiple desirable properties as a [[fertilizer]] especially under conditions of environmental stress.<ref>{{cite journal|last=Wahid|first=Abdul|date=2017-08-01|title=Thiourea: A Molecule with Immense Biological Significance for Plants|url=https://www.fspublishers.org/published_papers/27245_..pdf|journal=International Journal of Agriculture and Biology|volume=19|issue=4|pages=911–920|doi=10.17957/ijab/15.0464|issn=1560-8530|doi-access=free|access-date=2020-12-09|archive-date=2020-02-15|archive-url=https://web.archive.org/web/20200215101725/http://www.fspublishers.org/published_papers/27245_..pdf|url-status=live}}</ref> It may be applied in various capacities, such as a seed pretreatment (for priming), foliar spray or medium supplementation.

===Other uses===

Other industrial uses of thiourea include production of flame retardant resins, and [[Vulcanization#Vulcanization of polychloroprene|vulcanization]] accelerators.

Thiourea is building blocks to [[pyrimidine]] derivatives. Thus, thioureas condense with β-dicarbonyl compounds.<ref>{{cite journal |last1 = Foster|first1=H. M.|last2=Snyder|first2=H. R. | title = 4-Methyl-6-hydroxypyrimidine |journal=Organic Syntheses | volume = 35 | page = 80 | year = 1955 | doi = 10.15227/orgsyn.035.0080}}</ref> The amino group on the thiourea initially condenses with a carbonyl, followed by cyclization and tautomerization. Desulfurization delivers the pyrimidine. The pharmaceuticals [[thiobarbituric acid]] and [[sulfathiazole]] are prepared using thiourea.<ref name="Ullmann"/> [[4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole]] is prepared by the reaction of thiourea and [[hydrazine]].

Thiourea is used as an auxiliary agent in diazo paper, light-sensitive photocopy paper and almost all other types of copy paper.

It is also used to tone silver-gelatin photographic prints (see [[Photographic print toning#Sepia toning|Sepia Toning]]).

Thiourea is used in the Clifton-Phillips and Beaver bright and semi-bright electroplating processes.<ref>{{cite journal|title=81st Universal Metal Finishing Guidebook|journal=Metal Finishing, Guidebook and Directory Issue|date=Fall 2013|publisher=[[Metal Finishing Magazine]]|issn=0026-0576|pages=285|url=http://metalfinishing.epubxp.com/t/12238-metal-finishing-guide-book|access-date=2016-10-11|archive-date=2017-11-17|archive-url=https://web.archive.org/web/20171117133018/http://metalfinishing.epubxp.com/t/12238-metal-finishing-guide-book|url-status=live}}</ref> It is also used in a solution with tin(II) chloride as an electroless tin plating solution for copper [[printed circuit board]]s.

Thioureas are used (usually as [[Hydrogen-bond catalysis|hydrogen-bond donor catalysts]]) in a research theme called [[thiourea organocatalysis]].<ref>{{cite journal|first=Peter |last=R. Schreiner |title=Metal-free organocatalysis through explicit hydrogen bonding interactions |journal=Chem. Soc. Rev. |date=2003 |volume=32 |issue=5 |pages=289–296 |doi=10.1039/b107298f |pmid=14518182}}</ref> Thioureas are often found to be stronger hydrogen-bond donors (''i.e.,'' more acidic) than [[urea]]s.<ref>{{cite journal |last1=Jakab |first1=Gergely |last2=Tancon |first2=Carlo |last3=Zhang |first3=Zhiguo |last4=Lippert |first4=Katharina M. |last5=Schreiner |first5=Peter R. |title=(Thio)urea Organocatalyst Equilibrium Acidities in DMSO |journal=Organic Letters |date=2012 |volume=14 |issue=7 |pages=1724–1727 |doi=10.1021/ol300307c|pmid=22435999}}</ref><ref>{{cite journal |last1=Nieuwland |first1=Celine |last2=Fonseca Guerra |first2=Célia |title=How the Chalcogen Atom Size Dictates the Hydrogen-Bond Donor Capability of Carboxamides, Thioamides, and Selenoamides |journal=Chemistry – A European Journal |date=2022 |volume=28 |issue=31 |page=e202200755 |doi=10.1002/chem.202200755|pmid=35322485 |pmc=9324920}}</ref>

==Reactions==

The material has the unusual property of changing to [[ammonium thiocyanate]] upon heating above {{val|130|ul=°C}}. Upon cooling, the ammonium salt converts back to thiourea.{{citation needed|date=February 2019}}

===Reductant===

Thiourea reduces peroxides to the corresponding [[diol]]s.<ref>{{cite journal|first1=C.|last1=Kaneko|first2=A.|last2=Sugimoro|first3=S.|last3=Tanaka|title=A facile one-step synthesis of ''cis''-2-cyclopentene and ''cis''-2-cyclohexene-1,4-diols from the corresponding cyclodienes|url=https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-1974-23462|journal=[[Synthesis (journal)|Synthesis]]|pages=876–877|year=1974|doi=10.1055/s-1974-23462|volume=1974|issue=12|s2cid=93207044 |access-date=2022-06-18|archive-date=2021-06-12|archive-url=https://web.archive.org/web/20210612083502/https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-1974-23462|url-status=live}}</ref> The intermediate of the reaction is an unstable [[endoperoxide]].

[[Image:Diol.png|center|400px|reduction of cyclic peroxide]]

Thiourea is also used in the reductive workup of [[ozonolysis]] to give [[carbonyl]] compounds.<ref>{{cite journal | author = Gupta, D., Soman, G., and Dev, S. | title = Thiourea, a convenient reagent for the reductive cleavage of olefin ozonolysis products | journal = [[Tetrahedron (journal)|Tetrahedron]] | pages = 3013–3018 | year = 1982 | doi = 10.1016/0040-4020(82)80187-7 | volume = 38 | issue = 20}}</ref> [[Dimethyl sulfide]] is also an effective reagent for this reaction, but it is highly volatile (boiling point&nbsp;{{val|37|u=°C}}) and has an obnoxious odor whereas thiourea is odorless and conveniently non-volatile (reflecting its polarity).

[[Image:Reduction cleavage.png|center|350px|reduction cleavage of product from ozonolysis]]

===Source of sulfide===

Thiourea is employed as a source of sulfide, such as for converting [[alkyl halide]]s to thiols. The reaction capitalizes on the high [[Nucleophilic substitution|nucleophilicity]] of the sulfur center and easy hydrolysis of the intermediate [[isothiouronium salt]]:

:{{chem2|CS(NH2)2 + RX → RSC(NH2)2+X−}}

:{{chem2|RSC(NH2)2+X− + 2 NaOH → RSNa + OC(NH2)2 + NaX + H2O}}

:{{chem2|RSNa + HCl → RSH + NaCl}}

In this example, [[ethane-1,2-dithiol]] is prepared from [[1,2-dibromoethane]]:<ref>{{OrgSynth | author = Speziale, A. J. | title = Ethanedithiol | collvol = 4 | collvolpages = 401 | year = 1963 | prep = cv4p0401}}</ref>

:{{chem2|C2H4Br2 + 2 SC(NH2)2 → [C2H4(SC(NH2)2)2]Br2}}

:{{chem2|[C2H4(SC(NH2)2)2]Br2 + 2 KOH → C2H4(SH)2 + 2 OC(NH2)2 + 2 KBr}}

Like other [[thioamide]]s, thiourea can serve as a source of sulfide upon reaction with metal ions. For example, [[mercury sulfide]] forms when mercuric salts in aqueous solution are treated with thiourea:

:{{chem2|Hg(2+) + SC(NH2)2 + H2O → HgS + OC(NH2)2 + 2 H+}}

These sulfiding reactions, which have been applied to the synthesis of many metal sulfides, require water and typically some heating.<ref>{{cite journal|last1=Liang|first1=Y.|last2=et|first2=al.|title=An efficient precursor to synthesize various FeS2 nanostructures via a simple hydrothermal synthesis method |journal=CrystEngComm |date=2016|volume=18|issue=33|pages=6262–6271|doi=10.1039/c6ce01203e}}</ref><ref>{{cite journal|last=Bao, N. |display-authors=etal |date=2007|title=Facile Cd−Thiourea Complex Thermolysis Synthesis of Phase-Controlled CdS Nanocrystals for Photocatalytic Hydrogen Production under Visible Light|journal=The Journal of Physical Chemistry C|volume=111|issue=47 |pages=17527–17534|doi=10.1021/jp076566s}}</ref>

=== Precursor to heterocycles ===

Thioureas are building blocks to [[pyrimidine]] derivatives. Thus thioureas condense with β-dicarbonyl compounds.<ref>{{OrgSynth | author = Foster, H. M., and Snyder, H. R. | title = 4-Methyl-6-hydroxypyrimidine | collvol = 4 | collvolpages = 638 | year = 1963 | prep = cv4p0638}}

</ref> The amino group on the thiourea initially condenses with a carbonyl, followed by cyclization and tautomerization. Desulfurization delivers the pyrimidine.

:[[Image:Pyrimidine.png|500px]]

Similarly, aminothiazoles can be synthesized by the reaction of α-halo[[ketone]]s and thiourea.<ref>{{cite journal |author1=Dodson, R. M. |author2=King, L. C. |name-list-style=amp | title = The reaction of ketones with halogens and thiourea | journal = [[J. Am. Chem. Soc.]] | volume = 67 | pages = 2242–2243 | year = 1945 | doi = 10.1021/ja01228a059 | pmid=21005695 | issue = 12}}</ref>

:[[Image:Aminothiazole.png|500px]]

The pharmaceuticals [[thiobarbituric acid]] and [[sulfathiazole]] are prepared using thiourea.<ref name=Ullmann/> [[4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole]] is prepared by the reaction of thiourea and [[hydrazine]].

===Silver polishing===

According to the label on consumer products ''TarnX''<ref>{{cite web|url=https://cf1.bettymills.com/product/more_info/TX-4PRO.pdf|title=Tarn-X PRO Tarnish Remover|publisher=The Betty Mills Company, Inc.|access-date=2021-06-06|archive-date=2021-06-06|archive-url=https://web.archive.org/web/20210606174511/https://cf1.bettymills.com/product/more_info/TX-4PRO.pdf|url-status=live}}</ref> and ''Silver Dip'',<ref>{{cite web|url=https://www.jlsmithco.com/wp-content/uploads/2020/05/hagerty-silver-dip-1-gal.jpg|title=Hagerty Silver Dip|publisher=J.L. Smith & Co.|access-date=2021-06-06|archive-date=2021-06-06|archive-url=https://web.archive.org/web/20210606174511/https://www.jlsmithco.com/wp-content/uploads/2020/05/hagerty-silver-dip-1-gal.jpg|url-status=live}}</ref> the liquid silver cleaning products contain thiourea along with a warning that thiourea is a chemical on [[California]]'s list of carcinogens.<ref>{{cite report|url=https://oehha.ca.gov/media/downloads/proposition-65/report/expcancer.pdf|title=Expedited Cancer Potency Values and Proposed Regulatory Levels for Certain Proposition 65 Carcinogens|date=April 1992|access-date=2022-06-18|archive-date=2022-01-21|archive-url=https://web.archive.org/web/20220121224113/https://oehha.ca.gov/media/downloads/proposition-65/report/expcancer.pdf|url-status=live}}</ref> A [[lixiviant]] for gold and silver leaching can be created by selectively oxidizing thiourea, bypassing the steps of cyanide use and smelting.<ref>{{cite web|first=Anthony|last=Esposito|archive-url=https://web.archive.org/web/20090217115008/http://www.bnamericas.com/story.jsp?idioma=I&sector=7&noticia=399641|archive-date=17 February 2009|url=http://www.bnamericas.com/story.jsp?idioma=I&sector=7&noticia=399641|url-status=dead|title=Peñoles, UAM unveil pilot thiourea Au-Ag leaching plant in Mexico|publisher=Business News Americas|date=July 13, 2007}}</ref>

===Kurnakov reaction===

Thiourea is an essential reagent in the [[Kurnakov test]] used to differentiate [[Cis–trans isomerism|cis- and trans-]] isomers of certain square planar [[platinum]] complexes. The reaction was discovered in 1893 by Russian chemist [[Nikolai Kurnakov]] and is still performed as an assay for compounds of this type.<ref>{{cite journal|last=Kauffman|first=George B.|date=January 1983|title=Nikolaĭ Semenovich Kurnakov, the reaction (1893) and the man (1860–1941) a ninety-year retrospective view|url=https://www.sciencedirect.com/science/article/pii/S027753870081400X|journal=Polyhedron|language=en|volume=2|issue=9|pages=855–863|doi=10.1016/S0277-5387(00)81400-X|issn=0277-5387|access-date=2020-12-09|archive-date=2021-03-28|archive-url=https://web.archive.org/web/20210328190216/https://www.sciencedirect.com/science/article/abs/pii/S027753870081400X|url-status=live}}</ref>

==Safety==

The {{LD50}} for thiourea is {{val|125|u=mg/kg}} for rats (oral).<ref name="msds">{{cite web|url=http://gis.dep.wv.gov/tri/cheminfo/msds1385.txt|title=Thiourea and its properties|date=September 11, 1986|access-date=January 6, 2012|archive-date=May 27, 2010|archive-url=https://web.archive.org/web/20100527182536/http://gis.dep.wv.gov/tri/cheminfo/msds1385.txt|url-status=live}}</ref>

A [[goitrogen]]ic effect (enlargement of the thyroid gland) has been reported for chronic exposure, reflecting the ability of thiourea to interfere with iodide uptake.<ref name=Ullmann/>

A cyclic derivative of thiourea called [[Thiamazole]] is used to treat overactive thyroid

==See also==

*[[Thioureas]]

==References==

{{reflist|30em}}

==Further reading==

*{{cite book|title=The Chemistry of Double-Bonded Functional Groups|url=https://books.google.com/books?id=5h8SAQAAMAAJ|url-access=limited |first=Saul|last=Patai|pages=[https://archive.org/details/chemistryfunctio01pata/page/n1360 1355]–1496|publisher=John Wiley & Sons|location=New York, NY|date=1977|oclc=643207498|isbn=9780471924937}}

==External links==

*[https://www.inchem.org/documents/cicads/cicads/cicad49.htm INCHEM assessment of thiourea]

*[https://www.inchem.org/documents/icsc/icsc/eics0680.htm International Chemical Safety Card 0680]

{{Thyroid hormone receptor modulators}}

{{Authority control}}

[[Category:Functional groups]]

[[Category:Thioureas| ]]