[CH3:1][C:2](=[O:7])[C:3]([CH3:6])([CH3:5])[CH3:4].[CH:8]1[C:13]([CH:14]=O)=[CH:12][C:11]2[O:16][CH2:17][O:18][C:10]=2[CH:9]=1.[OH-].[Na+]>C(O)C.O>[O:18]1[C:10]2[CH:9]=[CH:8][C:13]([CH:14]=[CH:1][C:2](=[O:7])[C:3]([CH3:6])([CH3:5])[CH3:4])=[CH:12][C:11]=2[O:16][CH2:17]1To a mixture of pinacolone (55 g) and piperonal (75 g) in ethanol (200 ml) was added a sodium hydroxide (5.0 g) in water (115 ml) solution. The mixture solidified after stirring at room temperature for 2 days. Filtration collected 137 g of solid which was then dissolved in ethyl acetate (500 ml), washed with water (500 ml), and dried over anhydrous magnesium sulfate. Concentration and trituration in hexane yielded 104.5 g of colorless solid product, mp 94°-96° C. Using essentially the same procedures, additional alpha, beta-unsaturated ketones were prepared as intermediates and are listed in Table 5. [see Pace, E, Atti Acad Lincei, [6], 9, 778 (1929); Chemical Abstracts, 23, 4942, 1929].
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