2-Methylimidazole → 4-(2-Methyl-1H-imidazol-1-yl)benzaldehyde

To a suspension of NaH (0.612 g, 15.3 mmol : 60% suspension of mineral oil) of in dry DMF (10 ml) cooled to 10° C. was added a DMF (8 ml) solution of 2-methylimidazole (1.23 g, 15 mmol) under a nitrogen atmosphere, and the mixture was stirred for 30 min at room temperature. 4-Fluorobenzaldehyde (1.90 g, 15.3 mmol) was added to the reaction mixture, and the resulting solution was stirred for 14 h. The reaction mixture was poured into an ice-cold saturated aqueous NH4Cl solution (100 ml) and extracted with ethyl acetate (100 ml×2). The organic layer was washed with water (100 ml) and brine (80 ml), dried over MgSO4 and the solvent removed under reduced pressure. The resultant residue was purified by column chromatography (SiO2 ; hexane:ethyl acetate=1:1 then ethyl acetate) to give crude 4-(2-methylimidazol-1-yl)-benzaldehyde (1.0 g), which was used without further purification.