# Allocinnamic acid

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> Source: https://en.wikipedia.org/wiki/Allocinnamic_acid
> Source revision: 1330258353
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{{Chembox
<!-- Images -->
| Name           = Allocinnamic acid
| ImageFile      = Аллокоричная кислота.svg
| ImageSize      = 100px
| ImageAlt       = <!-- Names -->
| IUPACName      = (''Z'')-3-phenylprop-2-enoic acid
| OtherNames     = ''cis''-''β''-carboxystyrene, ''cis''-cinnamic acid;
| Section1       = {{Chembox Identifiers
| CASNo          = 102-94-3
| CASNo_Ref      = {{Cascite|correct|CAS}}
| ChemSpiderID   = 10286933
| DTXSID         = DTXSID001019000
| EC_number      = 827-073-9
| ChEBI          = 35699
| ChEMBL         = 
| Gmelin = 279588
| KEGG           = 
| UNII           = YB7ZGY8NE2
| PubChem        = 5372954
| InChI          = InChI=1S/C9H8O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-7H,(H,10,11)/b7-6-
| InChIKey       = WBYWAXJHAXSJNI-SREVYHEPSA-N
| SMILES         = C1=CC=C(C=C1)C=CC(=O)O
}}
| Section2       = {{Chembox Properties
| H=8|O=6|C=9 
| MolarMass      = 
| Appearance     = colorless crystals
| Density        = 1.49 g/cm³
| MeltingPtC     = 68
| BoilingPtC     = 265 
| BoilingPt_ref  = 
| Solubility     = soluble
  }}
| Section3       = {{Chembox Hazards
| GHSPictograms  = 
| GHSSignalWord  = 
| GHS_ref        =
| HPhrases       = 
| PPhrases       = 
| MainHazards    = 
| FlashPt        = 
| AutoignitionPt = 
  }}
}}
'''Allocinnamic acid''' is a ''cis''-isomer of [cinnamic acid](/source/cinnamic_acid), into which the cinnamic acid is easily converted.<ref>{{cite web |last1=Informatics |first1=NIST Office of Data and |title=(Z)-3-Phenyl-2-propenoic acid |url=https://webbook.nist.gov/cgi/cbook.cgi?ID=C102943 |publisher=[NIST](/source/NIST) |access-date=13 June 2025 |language=en}}</ref><ref>{{cite book |last1=Senning |first1=Alexander |title=Elsevier's Dictionary of Chemoetymology: The Whys and Whences of Chemical Nomenclature and Terminology |date=30 October 2006 |publisher=[Elsevier](/source/Elsevier) |isbn=978-0-08-048881-3 |page=14 |url=https://books.google.com/books?id=Fl4sdCYrq3cC&dq=Allocinnamic+acid&pg=PA14 |access-date=13 June 2025 |language=en}}</ref>

==Synthesis==
Allocinnamic acid was first discovered by [Carl Liebermann](/source/Carl_Liebermann) in 1890 in coca leaves,<ref name="QJ"/><ref>{{cite book |last1=Gattermann |first1=Ludwig |title=The Practical Methods of Organic Chemistry |date=1896 |publisher=Macmillan |page=268 |url=https://books.google.com/books?id=IR2-Lhipf30C&dq=Allocinnamic+acid&pg=PA268 |access-date=13 June 2025 |language=en}}</ref> then Liebermann found that this acid is formed during the reduction (by zinc dust in an alcoholic solution during boiling) of ''β''-dibromopropiolic acid.

==Physical properties==
Allocinnamic acid crystallizes in the form of three crystalline modifications with melting points of 68 °C, 58 °C, and 42 °C.<ref>{{cite book |last1=Whitmore |first1=Frank C. |title=Organic Chemistry, Volume Two: Part III: Aromatic Compounds Part IV: Heterocyclic Compounds Part V: Organophosphorus and Organometallic Compounds |date=14 December 2011 |publisher=[Courier Dover Publications](/source/Courier_Dover_Publications) |isbn=978-0-486-60701-6 |page=703 |url=https://books.google.com/books?id=jgZLDwAAQBAJ&dq=Allocinnamic+acid++sulfuric+acid,&pg=PA703 |access-date=13 June 2025 |language=en}}</ref><ref>{{cite book |title=Ullmann's Fine Chemicals |date=7 January 2014 |publisher=[John Wiley & Sons](/source/John_Wiley_%26_Sons) |isbn=978-3-527-68359-8 |url=https://books.google.com/books?id=yZqOAgAAQBAJ&dq=Allocinnamic+acid&pg=PA427 |access-date=13 June 2025 |language=en}}</ref> It is hardly soluble in water and cold [ligroin](/source/ligroin), easily soluble in alcohol and ether, and does not change in dim light.<ref>{{cite journal |last1=Lee |first1=Ho-Hi |last2=Senda |first2=Hitoshi |last3=Kuwae |first3=Akio |last4=Hanai |first4=Kazuhiko |title=Crystal and Molecular Structures of Allocinnamic Acid |journal=[Bulletin of the Chemical Society of Japan](/source/Bulletin_of_the_Chemical_Society_of_Japan) |date=1 May 1994 |volume=67 |issue=5 |pages=1475–1478 |doi=10.1246/bcsj.67.1475 |url=https://academic.oup.com/bcsj/article-abstract/67/5/1475/7349270?redirectedFrom=fulltext |access-date=13 June 2025|url-access=subscription }}</ref>

==Chemical properties==
When heated briefly with concentrated [sulfuric acid](/source/sulfuric_acid), the compound turns into cinnamic acid.<ref name="QJ">{{cite book |title=Quarterly Journal of the Chemical Society of London |date=1890 |publisher=Chemical Society (Great Britain) |page=1417 |url=https://books.google.com/books?id=rALzAAAAMAAJ&dq=Allocinnamic+acid++sulfuric+acid,&pg=PA1417 |access-date=13 June 2025 |language=en}}</ref> 

It forms liquid anhydride with [acetic anhydride](/source/acetic_anhydride), which turns into cinnamic acid anhydride when heated.

== References ==
<references/>

Category:Aromatic acids
Category:Phenylpropanoids

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Adapted from the Wikipedia article [Allocinnamic acid](https://en.wikipedia.org/wiki/Allocinnamic_acid) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Allocinnamic_acid?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.