In 30 ml of DMF, 2.9 g of the compound (3) obtained in Example 3 were dissolved, followed by the addition of 0.59 g of 4-aminomethylpyridine. The resultant mixture was stirred at room temperature, to which 0.60 g of t-BuOK was added under ice cooling. The thus-obtained mixture was stirred at room temperature for 5 hours. The DMF was distilled off under reduced pressure, and the residue was dissolved in CHCl3. The solution so obtained was washed with water and then dried over anhydrous magnesium sulfate (MgSO4). The solvent was distilled off under reduced pressure. The residue was isolated and purified by chromatography on a silica gel column (eluent: CHCl3/MeOH=7/3), whereby 0.41 g of the compound (4) was obtained (yield: 18%).
