Hydrogen Bromide → 2-Amino-6-(2-furyl)-5-(6-oxo-1,6-dihydro-3-pyridinyl)nicotinonitrile

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Reaction Steps

A solution of 2-amino-6-(2-furyl)-5-(4-methoxy-3-pyridyl)-3-pyridinecarbonitrile (1.0 g, 3.42 mmol) in acetic acid (6 ml)-conc. hydrobromic acid (10 ml) was stirred at 100° C. for 1.5 hours. After cooling as it was, the reaction solution was adjusted to pH 12 to 13 with 5 N sodium hydroxide and washed with ethyl acetate. The organic layer was extracted with 1 N sodium hydroxide (×2), and then the combined aqueous layer was neutralized with 5 N hydrochloric acid. The resulting solid was collected by filtration, to give the title compound (760 mg) as yellow crude crystals. After suspending the product in methanol, 4 N HCl/ethyl acetate was added thereto to dissolved and it subjected to silica gel column chromatography (elution solvent; dichloromethane, dichloromethane:methanol=40:1, 20:1, 10:1). The resulting crude objective compound was suspended in water, and then neutralized with 5 N sodium hydroxide. The solid was collected by filtration and washed with water, to give the title compound (486 mg, 51%) as a yellow solid.

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