View source for Chemistry:2-Hydroxy-3-methyl-2-cyclopenten-1-one

{{chembox
| Verifiedfields = 
| verifiedrevid = 
| ImageFile = MeC5-ol-one.png
| ImageSize = 120px
| PIN = 3-Methylcyclopentane-1,2-dione
| OtherNames = Maple lactone, Methylcyclopentenolone, Corylon
|Section1={{Chembox Identifiers
| Abbreviations =
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 55153
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 627E92X64B
| InChIKey = 
| ChEBI_Ref = {{ebicite|changed|EBI}} 
| ChEBI = 
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C6H8O2/c1-4-2-3-5(7)6(4)8/h4H,2-3H2,1H3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = OACYKCIZDVVNJL-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 765-70-8
| CASNo1 = 80-71-7
| CASNo1_Comment = ([[Biology:Enol|enol]] form)
| SMILES = CC1C(=O)C(=O)CC1
| EINECS = 212-154-8
| PubChem = 61209
| PubChem1 = 6660
| PubChem1_Comment = (enol form)
}}
|Section2={{Chembox Properties
| Density = 1.312 g/cm<sup>3</sup>
| C=6 | H=8 | O=2
| MeltingPtC = 104-108
| MeltingPt_ref = <ref>[http://www.sigmaaldrich.com/catalog/product/aldrich/w270027?lang=en 3-Methyl-1,2-cyclopentanedione] at Sigma Aldrich</ref>
}}
|Section7={{Chembox Hazards
| ExternalSDS =
| MainHazards =
| NFPA-H =
| NFPA-F =
| NFPA-R =
| NFPA-S =
| FlashPtC = 
| AutoignitionPtC =
| ExploLimits = 
}}
}}

'''2-Hydroxy-3-methyl-2-cyclopenten-1-one'''  is an [[Chemistry:Organic compound|organic compound]] related to [[Chemistry:1,2-Cyclopentanedione|1,2-cyclopentanedione]].  It is the [[Biology:Enol|enol]] [[Chemistry:Tautomer|tautomer]] of the diketone 3-methylcyclopentane-1,2-dione.  Being an enol, the compound is often called methylcyclopentenolone.  It is a colorless solid.

==Synthesis and structure==
The compound is prepared by base-catalyzed condensation of 1‐hydroxyhexane‐2,5‐dione, a derivative of [[Chemistry:Hydroxymethylfurfural|hydroxymethylfurfural]].<ref name=CSC/>

The structure has been confirmed by [[Physics:X-ray crystallography|X-ray crystallography]].<ref name=CSC>{{cite journal|doi=10.1002/cssc.201702100|title=Cyclopentanone Derivatives from 5-Hydroxymethylfurfural via 1-Hydroxyhexane-2,5-dione as Intermediate|year=2018|last1=Wozniak|first1=Bartosz|last2=Spannenberg|first2=Anke|last3=Li|first3=Yuehui|last4=Hinze|first4=Sandra|last5=De Vries|first5=Johannes G.|journal=ChemSusChem|volume=11|issue=2|pages=356–359|pmid=29235723}}</ref>
Quantum calculations also indicate that the enol is strongly favored relative to the diketo tautomer.  Furthermore, the enolization occurs at the methyl-substituted carbon.<ref>{{cite journal|doi=10.1080/00268976.2011.646336|title=Quantum Mechanical Study of the Tautomerism and Molecular Spectra of 2-Hydroxy-3-methyl-2-cyclopenten-1-one|year=2012|last1=Zborowski|first1=Krzysztof K.|last2=Grybos|first2=Ryszard|last3=Wesełucha-Birczyńska|first3=Aleksandra|last4=Kim|first4=Younkyoo|last5=Proniewicz|first5=Leonard M.|journal=Molecular Physics|volume=110|issue=6|pages=343–351|bibcode=2012MolPh.110..343Z|s2cid=95003384}}</ref>

==Use and occurrence==
It is one of many products from the [[Chemistry:Pyrolysis|pyrolysis]] of lignocellulose.<ref>{{cite journal|doi=10.1039/C1EE01230D|title=Catalytic Conversion of Biomass-Derived Feedstocks into Olefins and Aromatics with ZSM-5: The Hydrogen to Carbon Effective Ratio|year=2011|last1=Zhang|first1=Huiyan|last2=Cheng|first2=Yu-Ting|last3=Vispute|first3=Tushar P.|last4=Xiao|first4=Rui|last5=Huber|first5=George W.|journal=Energy & Environmental Science|volume=4|issue=6|pages=2297|url=https://works.bepress.com/cgi/viewcontent.cgi?article=1022&context=george_huber}}</ref>

It is used in flavors and perfumery for its [[Chemistry:Maple sugar|maple]]- or [[Chemistry:Caramel|caramel]]-like odor.<ref>{{cite web | url = http://www.thegoodscentscompany.com/data/rw1012711.html | publisher = Good Scents Company | title = Cyclotene}}</ref>  It contributes to the flavor or odor of many foods including wines, coffee, paprika, and salmon.  It is sometimes called '''maple lactone''' because it occurs in maple syrup (it is not, however, a [[Chemistry:Lactone|lactone]]).<ref>{{cite journal|doi=10.1021/ed084p1647|title=The Chemical Composition of Maple Syrup|year=2007|last1=Ball|first1=David W.|journal=Journal of Chemical Education|volume=84|issue=10|pages=1647|bibcode=2007JChEd..84.1647B|s2cid=98149895 }}</ref>

==See also==
* [[Chemistry:1,2-Cyclopentanedione|1,2-Cyclopentanedione]]

==References==
{{reflist}}

{{DEFAULTSORT:Hydroxy-3-methyl-2-cyclopenten-1-one, 2-}}
[[Category:Diketones]]
[[Category:Cyclopentanes]]

{{Sourceattribution|2-Hydroxy-3-methyl-2-cyclopenten-1-one}}