3-Penten-2-one
{{Chembox
| ImageFile = Structural formula of (E)-3-Penten-2-one.svg
| ImageSize = 200px
| ImageAlt =
| PIN = Pent-3-en-2-one
| OtherNames = Ethylidene acetone
| Section1 = {{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 625-33-2
| CASNo_Comment = (unspecified)
| CASNo1_Ref = {{cascite|correct|CAS}}
| CASNo1 = 3102-33-8
| CASNo1_Comment = (E)
| CASNo2_Ref = {{cascite|correct|CAS}}
| CASNo2 = 3102-32-7
| CASNo2_Comment = (Z)
| PubChem = 12248
| PubChem_Comment = (unspecified)
| PubChem1 = 637920
| PubChem1_Comment = (E)
| PubChem2 = 5356572
| PubChem2_Comment = (Z)
| ChemSpiderID = 11747
| ChemSpiderID_Comment = (unspecified)
| ChemSpiderID1 = 553493
| ChemSpiderID1_Comment = (E)
| ChemSpiderID2 = 4512214
| ChemSpiderID2_Comment = (Z)
| EC_number = 210-888-3
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 4WN5NGB7KX
| UNII_Comment = (E)
| UNII1_Ref = {{fdacite|correct|FDA}}
| UNII1 = W8XX21WHYC
| UNII1_Comment = (Z)
| Beilstein = 3-01-00-02985
| InChI = 1S/C5H8O/c1-3-4-5(2)6/h3-4H,1-2H3
| InChI_Comment = (unspecified)
| InChIKey = LABTWGUMFABVFG-UHFFFAOYSA-N
| InChI1 = 1S/C5H8O/c1-3-4-5(2)6/h3-4H,1-2H3/b4-3+
| InChI1_Comment = (E)
| InChIKey1 = LABTWGUMFABVFG-ONEGZZNKSA-N
| InChI2 = 1S/C5H8O/c1-3-4-5(2)6/h3-4H,1-2H3/b4-3-
| InChI2_Comment = (Z)
| InChIKey2 = LABTWGUMFABVFG-ARJAWSKDSA-N
| SMILES = CC=CC(=O)C
| SMILES_Comment = (unspecified)
| Jmol = none
| SMILES1 = C/C=C/C(=O)C
| SMILES1_Comment = (E)
| SMILES2 = C/C=C\C(=O)C
| SMILES2_Comment = (Z)
}}
| Section2 = {{Chembox Properties
| C=5|H=8|O=1
| MolarMass =
| Appearance = colourless liquid{{GESTIS|Name=3-Penten-2-on|ZVG=106273|CAS=625-33-2|Date=25 July 2017}}
| Density = 0.861 g·cm−3
0,862 g·cm−3 (E){{citation|surname1=Carl L. Yaws|title=The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals Physical Properties for More Than 54,000 Organic and Inorganic Chemical Compounds, Coverage for C1 to C100 Organics and Ac to Zr Inorganics|publisher=Gulf Professional Publishing|page=72|isbn=978-0-12-801146-1|date= 2015|url=https://books.google.com/books?id=GutDBAAAQBAJ&pg=PA72
}}
| MeltingPt =
| BoilingPtC = 122
| Solubility = soluble in water, acetone and ether (E){{citation|surname1=William M. Haynes|title=CRC Handbook of Chemistry and Physics|edition=97th|publisher=CRC Press|page=440|isbn=978-1-4987-5429-3|date= 2016|url=https://books.google.com/books?id=VVezDAAAQBAJ&pg=PA440
}}
}}
| Section3 = {{Chembox Hazards
| MainHazards = Flammable and toxic
| ExternalSDS = [https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=145017&brand=ALDRICH&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F145017%3Flang%3Den Safety Data Sheet]
| FlashPt =
| AutoignitionPt =
| GHSSignalWord = Danger
| GHSPictograms = {{GHS02}}{{GHS07}}
| HPhrases = {{H-phrases|225|312|315|319|335}}
| PPhrases = {{P-phrases|210|233|240|241|242|243|261|264|271|280|302+352|303+361+353|304+340|305+351+338|312|321|322|332+313|337+313|362|363|370+378|403+233|403+235|405|501}}
}}
}}
3-Penten-2-one is an organic compound with the formula CH3C(O)CH=CHCH3. It exists as (E) and (Z) stereoisomers. The compound is classified as an α,β-unsaturated ketone. It is a colorless volatile liquid with fruity to pungent odor.{{cite web | url = https://www.alfa.com/en/catalog/L13031/ | title = L13031 3-Penten-2-one, tech. 85% | publisher = Alfa Aesar }}
Preparation, occurrence, uses
The (E) isomer is classically obtained from the 3-chloropentanone by dehydrohalogenation.{{cite journal|title=trans-3-Penten-2-one|author=H. C. Odom|author2=A. R. Pinder|name-list-style=amp|journal=Org. Synth.|year=1971|volume=51|page=115|doi=10.15227/orgsyn.051.0115}} It can also be obtained by dehydration of 4-hydroxy-pentan-2-one using oxalic acid as a catalyst.{{citation|surname1=George A. Burdock|title=Encyclopedia of Food and Color Additives|publisher=CRC Press|page=2997|isbn=978-0-8493-9414-0|date= 1997|url=https://books.google.com/books?id=NtaR9i3hYCYC&pg=PA2997}}
3-Penten-2-one occurs naturally in the berries of two species of Aronia melanocarpa.{{Sigma-Aldrich|Aldrich|145017|Date=25 July 2017|Name=3-Penten-2-one, 70%}} It has also been found in other plants and foods such as tomatoes, cocoa, tea, and potato chips.
3-Penten-2-one can be used for the synthesis of other compounds such as the alkaloids senepodine G and cermizine C, for example. It is also a useful flavoring agent.