0.33 ml portion of 2-bromopyridine was dissolved in 3 ml of THF, and the solution was cooled to −78° C., mixed with 2.2 ml of n-butyl lithium and then stirred at the same temperature for 30 minutes. This solution was poured at −78° C. into a solution prepared by dissolving 3-[2-(1,3-dihydro-2H-benzimidazol-2-ylidene)-3-(3-fluorophenyl)-3-oxopropanoyl]benzaldehyde in 10 ml of THF. This was slowly risen to room temperature and mixed with 50 ml of saturated ammonium chloride aqueous solution. This was extracted with ethyl acetate, dried with sodium sulfate and then concentrated, and the thus formed residue was purified by a silica gel column chromatography (chloroform:methanol=from 100:0 to 90:10). By subjecting the thus obtained reddish brown solid to salt formation with 4N HCl/EtOAC (0.2 ml), 151 mg (42%) of 2-(1,3-dihydro-2H-benzimidazol-2-ylidene)-1-(3-fluorophenyl)-3-{3-[hydroxy(pyridin-2-yl)methyl]phenyl}propane-1,3-dione hydrochloride (Example 11-1) was obtained. FA: 466
