[CH3:1][C:2]1[CH:9]=[CH:8][C:5]([CH:6]=O)=[CH:4][CH:3]=1.[CH3:10][C:11]([CH3:13])=[O:12].[OH-].[Na+].O>C(O)C>[CH3:1][C:2]1[CH:9]=[CH:8][C:5]([CH:6]=[CH:10][C:11](=[O:12])[CH:13]=[CH:1][C:2]2[CH:9]=[CH:8][C:5]([CH3:6])=[CH:4][CH:3]=2)=[CH:4][CH:3]=14-Methylbenzaldehyde (1aa, 1.50 ml, 12.7 mmol) and acetone (19, 0.47 ml, 6.4 mmol) were combined in ethanol (10 ml) and stirred for 15 min at room temperature. A solution of sodium hydroxide (0.52 g, 13.0 mmol) and water (10 ml) was added and the mixture stirred for 1 hr at room temperature. The resulting precipitate was filtered and recrystallized from ethanol to give 1.30 g (78%) of a yellow solid: mp 174-176° C. [expected mp 171-172° C.]; 1H NMR: δ 2.37 (s, 6H), 7.02 (d, 2H, J=15.9 Hz), 7.20 (d, 4H, J=8.0 Hz), 7.50 (d, 4H, J=7.9 Hz), 7.70 (d, 2H, J=15.9 Hz); 13C NMR: δ 21.6, 124.6, 128.3, 129.6, 132.1, 140.8, 143.0, 188.9.
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