Triphenylphosphine → 2-(3-Bromophenoxy)-3-[3-(3-hydroxypyridin-4-yl)propoxy]pyridine

Participants

Reaction Conditions

Reaction Steps

3-(3-Methoxymethoxypyridin-4-yl)-1-propanol (2.50 g, 12.7 mmol) obtained in Example 2 and triphenylphosphine (4.50 g, 17.0 mmol) are dissolved in THF (40 ml), and thereto are successively added with stirring diisopropyl azodicarboxylate (3.00 g, 15.0 mmol) and 2-(3-bromophenoxy)-3-pyridinol (2.50 g, 9.4 mmol) obtained in Reference Example 11 under ice-cooling. The mixture is further stirred at 40° C. for 30 minutes, and the reaction solution is concentrated under reduced pressure. To the residue is added ethyl acetate (50 ml), 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. To the residue are added ethanol (200 ml) and a 47% aqueous hydrobromic acid solution (20 ml), and the mixture is heated under reflux for 30 minutes. The reaction solution is concentrated under reduced pressure, and neutralized with a saturated aqueous sodium hydrogen carbonate solution, and 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: hexane/ethyl acetate/ethanol), recrystallized from ethanol/diethyl ether to give the title compound (3.10 g) as colorless crystals, m.p. 116-118° C.

Provenance & Evidence