Aldol condensation of benzaldehyde and acetone; trans-dibenzalacetone, (1E,4E)-1,5-Diphenyl-1,4-pentadien-3-one, DBA
SyntheticPage 771
DOI:
10.1039/SP771
Submitted Dec 19, 2014, published Dec 21, 2014
Matthew McBride (
mcbridemj@gmail.com), Jean-Claude Bradley (
)
A contribution from
UsefulChem
Chemicals Used
Benzaldehyde (Sigma Aldrich, 98%)
Acetone (Sigma Aldrich, 99%)
Sodium Hydroxide (NaOH)
Ethanol
Distilled Water
Procedure
A solution of NaOH (0.902 g, 22.55 mmol, 1.6 eq) in distilled water (40 mL) at room temperature was added to a stirred solution of benzaldehyde (4.361 g, 41.13 mmol, 2.9 eq) in ethanol (40 mL). Acetone (0.833 g, 14.36 mmol, 1.0 eq) was added to the reaction mixture. The reaction mixture was then stirred at room temperature for 30 minutes. The precipitated product was recovered by suction filtration, washed 1x with 2-3mL of 1:1 ethanol/water, dried over suction for 25 minutes, and recovered (3.044 g, 90.6%) as yellow crystals (mp 103-104°C).
Author's Comments
•This procedure produced pure trans-dibenzalacetone (verified by NMR spectroscopy) without having to recrystallize. However, the measured melting point of the product (103-104°C) is less than the literature value (110-112°C). If needed, the product may be recrystallized from ethanol.
•The benzaldehyde must be dissolved in the ethanol prior to addition to the water solution.
Data
1H NMR Spectrum (500 MHz, CDCl3): δ 7.72 (d, J = 16.3 Hz, 2H), δ 7.58 (m, 4H), δ 7.38 (m, 6H), δ 7.06 (d, J = 15.5 Hz, 2H)
Lead Reference
Other References
M. J. McBride, J. C. Bradley. UsefulChem, Experiment 284.
http://usefulchem.wikispaces.com/EXP284
Supplementary Information
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Keywords: Aldol Condensation
