To a solution (15 mL) of cyclohexyl(5-fluoro-3-methyl-1-benzofuran-2-yl)methanol (1.50 g) synthesized in Example A37(2) in toluene was added thionyl chloride (625 μL), and the mixture was stirred at room temperature for 3 hr. The reaction mixture was poured into ice-cooled saturated aqueous sodium hydrogen carbonate solution, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure to give a brown oil. To a mixture of the obtained oil, methyl 5-aminopyridine-2-carboxylate (957 mg), sodium iodide (1.71 g) and N,N-dimethylformamide (15 mL) was added sodium carbonate (1.21 g), and the mixture was stirred at 80° C. overnight. Saturated aqueous ammonium chloride solution was added to quench the reaction, and the reaction mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (10-50% ethyl acetate/hexane) to give the title object compound (909 mg, 40%) as a pale-brown solid.
