[CH3:1][CH:2]([CH3:13])[CH2:3][O:4][C:5]1[CH:12]=[CH:11][C:8]([CH:9]=O)=[CH:7][CH:6]=1.C(O)(=O)[CH2:15][C:16]([OH:18])=[O:17].N1C=CC=CC=1.[OH-].[Na+]>CCOCC>[CH3:1][CH:2]([CH3:13])[CH2:3][O:4][C:5]1[CH:12]=[CH:11][C:8]([CH:9]=[CH:15][C:16]([OH:18])=[O:17])=[CH:7][CH:6]=1A 500 mL, 1 neck, round-bottomed flask equipped with a magnetic stirrer and reflux condenser is charged with 4-(2-methylpropoxy)benzaldehyde (17.84 g, 0.100 mol, as from Example 2a), malonic acid (10.42 g, 0.100 mol), and 19 mL of pyridine. The mixture is heated with stirring in a 130° C. oil bath for 24 hours, then stirred at room temperature for 16 hours. The reaction mixture is then poured into a separatory funnel containing 300 mL of pH 12 aqueous sodium hydroxide and 300 mL of ether. The layers are separated and the aqueous phase washed with 150 mL of ether. The aqueous phase is then acidified with concentrated hydrochloric acid to bring the pH to 1 whereupon the powdery white acid precipitates out. The mixture is chilled in an ice/salt bath and the solid collected giving 5.89 g (0.027 mol, 27%) of product, m.p. 161°-164° C.
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