To a suspension of 60% sodium hydride (1.80 g) in tetrahydrofuran (50 mL) was added dropwise a solution of ethyl butyrylacetate (9.50 g) in tetrahydrofuran (30 mL). After stirring for 30 min, 4′-(bromomethyl)-2′-methoxybiphenyl-2-carbonitrile (8.79 g) was added. The mixture was stirred at room temperature for 15 hr, and 1 M hydrochloric acid was added. The mixture was extracted with ethyl acetate, and the organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated. The residue was purified by silica gel column chromatography to give ethyl 2-[(2′-cyano-2-methoxybiphenyl-4-yl)methyl]-3-oxohexanoate. Then, a solution of the obtained ethyl 2-[(2′-cyano-2-methoxybiphenyl-4-yl)methyl]-3-oxohexanoate, ethanimidamide hydrochloride (3.25 g) and 28% sodium methoxide (9.91 g) in methanol (70 mL) was stirred overnight. The solvent was evaporated under reduced pressure, and saturated aqueous ammonium chloride solution was added to the residue. The precipitated solid was collected by filtration, and washed with water and diethyl ether to give the title compound (5.63 g, 52%) as a white solid.
