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

{{Short description|Molecule with an amine directly attached to formic acid}}

{{distinguish|Carbonic acid}}

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| PIN = Carbamic acid<ref>{{cite book |author=[[International Union of Pure and Applied Chemistry]] |date=2014 |title=Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 |publisher=[[Royal Society of Chemistry|The Royal Society of Chemistry]] |pages=778 |doi=10.1039/9781849733069 |isbn=978-0-85404-182-4}}</ref>

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| UNII = O0UC6XOS4H

| PubChem = 277

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| MeSHName = Carbamic+acid

|Section2={{Chembox Properties

| Formula =

| N=1|H=3|C=1|O=2

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| = [[Dithiocarbamate]]<br />[[Carbonic acid]]<br />[[Urea]]<br />[[Ethyl carbamate]]

'''Carbamic acid''', which might also be called '''aminoformic acid''' or '''aminocarboxylic acid''',<ref>{{cite web |url=https://pubchem.ncbi.nlm.nih.gov/compound/Carbamic-acid |title=PubChem Compound Summary for CID 277, Carbamic acid |author=<!--Not stated--> |date=2020 |publisher=National Center for Biotechnology Information |access-date=October 10, 2020}}</ref> is the [[chemical compound]] with the formula {{chem2|H2NCOOH}}. It can be obtained by the reaction of [[ammonia]] {{chem2|NH3}} and [[carbon dioxide]] {{chem2|CO2}} at very low temperatures, which also yields [[ammonium carbamate]] {{chem2|[NH4]+[NH2CO2]-}}. The compound is stable only up to about 250 K (−23&nbsp;°C); at higher temperatures it decomposes into those two gases.<ref name=khan1999/> The solid apparently consists of [[dimer (chemistry)|dimer]]s, with the two molecules connected by [[hydrogen bond]]s between the two [[carboxyl]] groups –COOH.<ref name=boss2008>J. B. Bossa, P. Theulé, F. Duvernay, F. Borget and T. Chiavassa (2008): "Carbamic acid and carbamate formation in NH₃:CO₂ ices – UV irradiation versus thermal processes". ''Astronomy and Astrophysics'', volume 492, issue 3, pages 719-724. {{doi|10.1051/0004-6361:200810536}}</ref>

Carbamic acid could be seen as both an [[amine]] and [[carboxylic acid]], and therefore an [[amino acid]];<ref name=khan1999>R. K. Khanna and

M. H. Moore (1999): "Carbamic acid: molecular structure and IR spectra". ''Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy'', volume 55, issue 5, pages 961-967. {{doi|10.1016/S1386-1425(98)00228-5}} {{PMID|10347902}}{{bibcode|1999AcSpA..55..961K}}</ref> however, the attachment of the carboxyl group –COOH directly to the nitrogen atom (without any intermediate carbon chain) makes it behave very differently from the amino acids with intermediate carbon chain. ([[Glycine]] {{chem2|NH2CH2COOH}} is generally considered to be the simplest amino acid.) The [[hydroxyl]] group –OH attached to the carbon also excludes it from the [[amide]] class.

The term "carbamic acid" is also used generically for any compounds of the form RR′NCOOH, where R and R′ are [[organic compound|organic]] [[functional group|group]]s or hydrogen.<ref name=dijk2007/>

Deprotonation of a carbamic acid yields a [[carbamate]] anion {{chem2|RR′NCOO−}}, the salts of which can be relatively stable. Carbamate is also a term used for [[ester]]s of carbamic acids, such as [[methyl carbamate]] {{chem2|H2N\sC(\dO)\sOCH3}}. The '''carbamoyl''' [[functional group]] RR′N–C(=O)– (often denoted by '''Cbm''') is the carbamic acid molecule minus the OH part of the carboxyl.

==Structure==

Carbamic acid is a planar molecule.<ref name=khan1999/>

The {{chem2|H2N\s}} group of carbamic acid, unlike that of most amines, cannot be [[protonation|protonated]] to an [[ammonium]] group {{chem2|H3N+\s}}. The [[zwitterionic]] form {{chem2|H3N+\sCOO−}} is very unstable and promptly decomposes into ammonia and carbon dioxide,<ref name=chen2007>Y.-J. Chen, M. Nuevo, J.-M. Hsieh, T.-S. Yih, W.-H. Sun, W.-H. Ip, H.-S. Fung, S.-Y. Chiang, Y.-Y. Lee, J.-M. Chen and C.-Y. R. Wu (2007): "Carbamic acid produced by the UV/EUV irradiation of interstellar ice analogs". ''Astronomy and Astrophysics'', volume 464, issue 1, pages 253-257. {{doi|10.1051/0004-6361:20066631}}</ref> yet there is a report of its detection in ices irradiated with high-energy [[proton]]s.<ref name=khan1999/>

==Derivatives==

Carbamic acid is formally the parent compound of several important families of organic compounds:

<gallery>

File:Carbamic-acid-group-2D-L.png|carbamic acids

File:Carbamate-anion-generic-2D.png|carbamate anions

File:Carbamate-group-2D.png|carbamate esters

File:Carbamoyl-chloride-generic-2D.png|[[carbamoyl chloride]]s

</gallery>

===Carbamic acids===

Many substituted carbamic acids (RHNCOOH or RR′NCOOH), can be readily synthesized by bubbling carbon dioxide through solutions of the corresponding amine ({{chem2|RNH2}} or RR′NH, respectively) in an appropriate solvent, such as [[dimethyl sulfoxide|DMSO]] or [[supercritical fluid|supercritical]] carbon dioxide.<ref name=dijk2007>Z. J. Dijkstra, A. R. Doornbos, H. Weyten, J. M. Ernsting, C. J. Elsevier, and J. T. F. Keurentjes (2007): "Formation of carbamic acid in organic solvents and in supercritical carbon dioxide". ''Journal of Supercritical Fluids'', volume 41, issue 1, pages 109-114. {{doi|10.1016/j.supflu.2006.08.012}}</ref> These carbamic acids are generally unstable at room temperature, reverting to the parent amine and carbon dioxide.<ref>{{cite book | page = 63 | url =https://books.google.com/books?id=a3L7eYbsyhkC&pg=PT24 | isbn = 978-0-7817-4381-5 | first = Thomas L. | last = Lemke | year = 2003 | publisher = Lippincott, Williams & Wilkins | location = Philadelphia, PA | title = Review of Organic Functional Groups: Introduction to Medicinal Organic Chemistry }}</ref>

===Carbamate esters===

Unlike carbamic acids, carbamate esters are generally stable at room temperature as a higher state. They are prepared by reaction of [[carbamoyl chloride]]s with alcohols, the addition of alcohols to [[isocyanate]]s, and the reaction of carbonate esters with ammonia.<ref>{{cite book |doi=10.1002/14356007.a05_051 |chapter=Carbamates and Carbamoyl Chlorides |title=Ullmann's Encyclopedia of Industrial Chemistry |year=2000 |last1=Jäger |first1=Peter |last2=Rentzea |first2=Costin N. |last3=Kieczka |first3=Heinz |isbn=3527306730 }}</ref> [[Methyl carbamate]] and [[ethyl carbamate]] are among the simplest examples and have historically been used in the textile industry, both are now suspected carcinogens. [[Benzyl carbamate]] is also known.

==Occurrence in nature==

The [[enzyme]] class [[carbamate kinase]], involved in several [[metabolism|metabolic]] pathways of living organisms, [[catalysis|catalyzes]] the formation of [[carbamoyl phosphate]] {{chem2|H2N\sC(\dO)\sO\sPO3(2-)}}:

:{{chem2|[[adenosine triphosphate|ATP]] + NH3 + CO2 ⇌ [[adenosine diphosphate|ADP]] + H2N\sC(\dO)\sO\sPO3(2-)}}

An important example of an enzyme with this activity is [[carbamoyl phosphate synthetase]], e.g. [[carbamoyl phosphate synthetase I]] carrying out the first step of the [[urea cycle]] in order to dispose of waste ammonia.

One [[hemoglobin]] molecule can carry four molecules of carbon dioxide to the [[lung]]s as carbamate groups formed by reaction of {{chem2|CO2}} with four terminal amine groups of the [[deoxyhemoglobin|deoxy form]]. The resulting compound is called [[carbaminohaemoglobin]].

==Uses==

===Industrial===

Carbamic acid is an intermediate in the industrial production of [[urea]], which involves the reaction of carbon dioxide and ammonia.<ref name=Ullmann>{{ Ullmann | last1 = Meessen | first1 = J. H. |last2= Petersen |first2=H. | title = Urea | doi = 10.1002/14356007.a27_333 }}</ref>

:{{chem2|CO2 + NH3 → H2NCOOH}}

:{{chem2|H2NCOOH + NH3 → CO(NH2)2 + H2O}}

===Medical===

Some carbamate esters have use as [[muscle relaxant]]s, including [[Emylcamate]], [[Phenprobamate]], [[Styramate]] and other members of [[ATC_code_M03#M03BA_Carbamic_acid_esters|ATC code M03BA]]. These bind to the [[barbiturate]] site of the [[GABAA|GABA_A]] receptor.<ref>{{cite book | page = 495 | chapter-url = https://books.google.com/books?id=CeibVy3-LSMC&pg=PA495 | isbn = 978-0-7817-3481-3 | chapter = Central Nervous System Depressant | editor1-first = John H. |editor1-last=Block |editor2-first= John M. |editor2-last=Beale | year = 2004 | publisher = Lippincott, Williams & Wilkins | location = Philadelphia, PA | title = Wilson and Gisvold's Textbook of Organic Medicinal and Pharmaceutical Chemistry}}</ref>

===Insecticides===

Several carbamic acid based [[insecticide]]s have been developed; for example [[aldicarb]], [[carbaryl]], [[carbofuran]].<ref name=pmid3304999>{{cite journal |doi=10.2307/3430304 |pmid=3304999 |pmc=1474664 |jstor=3430304 |title=The Toxicologic Effects of the Carbamate Insecticide Aldicarb in Mammals: A Review |journal=Environmental Health Perspectives |volume=72 |pages=267–281 |year=1987 |last1=Risher |first1=John F. |last2=Mink |first2=Franklin L. |last3=Stara |first3=Jerry F. }}</ref>

===Chemical synthesis===

An amine functional group {{chem2|\sNH2}} can be [[protecting group|protected]] from unwanted reactions by being formed as carbamate ester [[functional group|residue]] –NHC(=O)–OR. [[Hydrolysis]] of the [[ester bond]] then produces a carbamic acid –NHC(=O)OH, which then loses carbon dioxide yielding the desired amine.

==References==

{{Reflist}}

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{{DEFAULTSORT:Carbamic Acid}}

[[Category:Carbamates]]