Into a 100-mL round-bottom flask, which was purged and maintained with an inert atmosphere of nitrogen, was placed methyl 3-(2-bromo-2-cyclopropylacetyl)-4-methylbenzoate (compound 4.6, 150 mg, 0.48 mmol), 2-methoxyacetimidamide hydrochloride (compound 4.7, 90 mg, 0.72 mmol), potassium carbonate (200 mg, 1.44 mmol), and N,N-dimethylformamide (15 mL). The resulting mixture was stirred at 80° C. for 3 h, then diluted with ethyl acetate (100 mL). The mixture was washed with brine (3×30 mL) and water (3×30 mL), dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was purified by silica gel chromatography with ethyl acetate/petroleum ether (1:2) as the eluent to yield methyl 3-(4-cyclopropyl-2-(methoxymethyl)-1H-imidazol-5-yl)-4-methylbenzoate (compound 4.8) (30 mg, 21%) and methyl 3-(4-cyclopropyl-2-(methoxymethyl)oxazol-5-yl)-4-methylbenzoate (compound 4.9) (60 mg, 41%), both as a yellow oils.
