C([Li])CCC.C(NC(C)C)(C)C.[N:13]1[CH:18]=[CH:17][CH:16]=[C:15]([CH2:19][C:20]([O:22][CH2:23][CH3:24])=[O:21])[CH:14]=1.[CH3:25][O:26][C:27]1[CH:28]=[C:29]([CH:32]=[CH:33][C:34]=1[O:35][CH3:36])[CH:30]=O>O1CCCC1.O>[CH3:25][O:26][C:27]1[CH:28]=[C:29](/[CH:30]=[C:19](/[C:15]2[CH:14]=[N:13][CH:18]=[CH:17][CH:16]=2)\[C:20]([O:22][CH2:23][CH3:24])=[O:21])[CH:32]=[CH:33][C:34]=1[O:35][CH3:36]
n-Butyllithium (1.6M hexane solution, 99.2 ml) was dropped into a solution of diisopropylamine (23.4 ml, 166.6 mmol) in tetrahydrofuran (320 ml). The obtained mixture was stirred at 0° C. for 30 minutes. A solution of ethyl 3-pyridylacetate (24.0 ml, 158.9 mmol) in tetrahydrofuran (20 ml) was dropped into the resulting mixture at -70° C. and the obtained mixture was stirred at 0° C. for 15 minutes. A solution of 3,4-dimethoxybenzaldehyde (27.6 g, 166.0 mmol) in tetrahydrofuran (100 ml) was dropped into the mixture at 0° C. The obtained mixture was stirred at room temperature overnight, followed by the addition of water. The obtained mixture was extracted with ether. The organic layer was washed with water and a saturated aqueous solution of common salt, dried over magnesium sulfate and concentrated. The oily residue was purified by flash column chromatography (ethyl acetate/hexane=3:2) to give the title compound as a pale yellow oil (18.19 g, yield: 37%).
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