3-(3,5-Dimethoxypyridin-4-yl)-1-propanol (0.60 g, 3.0 mmol) obtained in Example 1 and triphenylphosphine (1.18 g, 4.5 mmol) are dissolved in THF (30 ml), and thereto are successively added with stirring diisopropyl azodicarboxylate (0.78 g, 3.9 mmol) and 2-(3-bromophenoxy)-3-pyridinol (1.04 g, 3.9 mmol) obtained in Reference Example 11 under ice-cooling. The mixture is stirred at room temperature for 30 minutes, and the reaction; solution is concentrated under reduced pressure. To the residue is added ethyl acetate (50 m), and the mixture is extracted with a 10% aqueous hydrochloric acid solution (50 ml×2). The pH value of the aqueous layer is adjusted to pH 12 with potassium carbonate, and the mixture is extracted with ethyl acetate (100 ml×2). The organic layer is washed with a saturated brine (50 ml×2), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue is purified by silica gel column chromatography (eluent: chloroform/methanol) to give 2-(3-bromophenoxy)-3-[3-(3,5-dimethoxypyridin-4-yl)propoxy]pyridine, which is further treated with fumaric acid to give the title compound (1.26 g), m.p. 106-154° C.
