The alpha,beta-unsaturated carbonyl compound, E,E-dibenzylidene acetone (dba or 1,5-bis-penta-1E,4E-dien-3-one), is readily synthesised by simple base-mediated aldol condensation of two equivalents of benzaldehyde with acetone in the presence of sodium hydroxide in a water/ethanol solvent medium at room temperature (ref. 1). A literature survey reveals that other methods have been described. For example, a titanium tetralkoxide-induced aldol condensation has been reported for the synthesis of dba and derivatives (containing alkenic substitution) (ref. 2). Although this reaction occurs under neutral conditions, it requires up to 4 days to reach completion. An alternative procedure employs a partially dehydrated barium hydroxide catalyst (C-200, heterogeneous) for aldol condensation, under reflux with ethanol, to give dba in yields >95% in 1 h, although no substituted dba derivatives were reported (ref. 3). An indium trichloride mediated reaction of two equivalents of benzaldehyde with acetone provides dba in 88% yield, but requires 16 h reaction time at 110 degrees celcius in a sealed tube (ref. 4). A microwave assisted variant, mediated by KF-Al₂O₃, has further been reported from dba (ref. 5). We have established that the best practical method is the classic way using the simple base-mediated aldol condensation reaction. The KEY point is in the due care and attention required in the purification of these derivatives. Compounds were purified according to the following key: A: The product precipitates. Filtered and washed with ether. Filtrate concentrated in vacuo, then recrystallised from CH₂Cl₂. B: Extracted into CH₂Cl₂, washed with water, then sat. aq. NaCl, dried (MgSO₄) and concentrated in vacuo. Purified by flash chromatography using ethyl acetate/hexane mixtures. C: As for B, but then recrystallization with THF. D: As for A, but taken up in toluene (aldehyde insoluble in this). Filter, concentrate filtrate and recrystallize from hexane. R = 4-CH₃, (Method A); R = 4-t-Bu, (Method C); R = 4-OMe, (Method A);R = 2-OMe, (Method A); R = 4-CF₃, (Method A); R = 3-CF₃, (Method A); R = 2-CF₃, (Method A); R = 2,4,6-Me, (Method A); R = 2,4,6-OMe, (Method B); R = 4-F, (Method A); R = 4-Cl, (Method A); R = 4-Br, (Method D); R = 3-NO₂, (Method C); R = 4-NO₂, (Method C); R = 4-NMe₂, (Method B); R = 3,4,5-OMe, (Method B); R = 3,5-OMe, (Method B). The isolated yields in the vast majority of cases are very good, on a relatively large scale (5-50 g). If you are wondering what to do with all these dba derivatives, see ref. 6. A complete (non refereed paper has been prepared by our group and available at: http://www-users.york.ac.uk/%7Eijsf1/dba-derivatives.pdf).