To a solution of N-cyclopropylmethyl-N-[7-[2,6-dimethoxy-4-(methoxymethyl)phenyl]-2-(methoxymethyl)pyrazolo[1,5-a]pyridin-3-yl]amine (80 mg) dissolved in tetrahydrofuran (2 mL) was added tetrahydropyran-4-carbaldehyde (44 mg) and sodium triacetoxyborohydride (82 mg), and the reaction mixture was stirred for 30 minutes at room temperature. Water and saturated aqueous sodium bicarbonate were added to the reaction mixture, extraction was performed with ethyl acetate and the organic extract was washed with brine. The organic extract was dried over anhydrous magnesium sulfate and filtered, the solvent was evaporated under reduced pressure, the residue was purified by silica gel column chromatography and the title compound (63 mg) was obtained as a yellow oil from the n-hexane:ethyl acetate (1:2) fraction.
