Benzylideneacetone

Benzylideneacetone
IUPAC name 4-Phenyl-3-buten-2-one
Other names Benzalacetone Benzylideneacetone Methyl styryl ketone Benzylidene acetone
Identifiers
CAS number	122-57-6 Y, 1896-62-4 (trans)
ChemSpider	21106584 Y
ChEBI	CHEBI:217301 Y
ChEMBL	CHEMBL73639
RTECS number	EN0330000
Jmol-3D images	Image 1
SMILES CC(=O)/C=C/c1ccccc1
InChI InChI=1S/C10H10O/c1-9(11)7-8-10-5-3-2-4-6-10/h2-8H,1H3/b8-7+ Y Key: BWHOZHOGCMHOBV-BQYQJAHWSA-N Y InChI=1/C10H10O/c1-9(11)7-8-10-5-3-2-4-6-10/h2-8H,1H3/b8-7+ Key: BWHOZHOGCMHOBV-BQYQJAHWBQ
Properties
Molecular formula	C10H10O
Molar mass	146.19 g/mol
Appearance	pale yellow solid
Density	1.008 g/cm3
Melting point	39-42 °C
Boiling point	260-262 °C
Solubility in water	1.3 g/L
Solubility in other solvents	nonpolar solvents
Hazards
R-phrases	36/37/38-43
S-phrases	22-26-36/37
Main hazards	irritant
Flash point	116 °C
Related compounds
Related compounds	Dibenzylideneacetone cinnamaldehyde
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Benzylideneacetone is the organic compound described by the formula C₆H₅CH=CHC(O)CH₃. Although both cis- and trans-isomers are possible for the α,β-unsaturated ketone, only the trans isomer is observed. Its original preparation demonstrated the scope of condensation reactions to construct new, complex organic compounds.^[1]

Preparation

Benzylideneacetone can be efficiently prepared by the NaOH-induced condensation of the readily available reagents acetone and benzaldehyde:^[2]

CH₃C(O)CH₃ + C₆H₅CHO → C₆H₅CH=CHC(O)CH₃ + H₂O

Reactions

As with most methyl ketones, benzylidineacetone is moderately acidic at the alpha position, and it can be readily deprotonated to form the corresponding enolate^[3]

The compound undergoes the other reactions expected for its collection of functional groups: e.g., the double bond adds bromine, the heterodiene adds electron-rich alkenes in Diels-Alder reactions to give dihydropyrans, the methyl group undergoes further condensation with benzaldehyde to give dibenzylideneacetone, and the carbonyl forms hydrazones. It reacts with Fe₂(CO)₉ to give (benzylideneacetone)Fe(CO)₃, a reagent for transferring the Fe(CO)₃ unit to other organic molecules.^[4]

References

1. ^ Claisen, L. “Über die Einwirkung von Aceton auf Furfural und auf Benzaldehyd bei Gegenwart von Alkalilauge” Berichte der deutschen chemischen Gesellschaft 1881, volume 14, p 2468-2471.
2. ^ Drake, N. L.; Allen, Jr. P., "Benzalacetone", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0077 ; Coll. Vol. 1: 77 
3. ^ Danheiser, R. L.; Miller, R. F.; Brisbois, R. G. (1990), "Detrifluoroacetylative Diazo Group Transfer: (E)-1-Diazo-4-phenyl-3-buten-2-one", Org. Synth. 73: 134, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV9P0197 ; Coll. Vol. 9: 197 
4. ^ Knölker, H.-J. "(η⁴-Benzylideneacetone)tricarbonyliron" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.