4-Fluoro-3-methylbenzonitrile (0.052 g) and cesium carbonate (0.150 g) were added to a solution of compound (1d) (0.092 g) in 1-methyl-2-pyrrolidone (hereinafter referred to as NMP) (1.0 mL), followed by stirring at 120° C. for 60 hr. Water was added to the reaction solution, and the precipitate was collected by filtration and was washed by sprinkling water to obtain 3-methyl-4-{4-(quinolin-3-yl)-3-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-1-yl}benzonitrile (11%). According to Example 1(7), compound (82) (64%) was prepared as a white solid using 3-methyl-4-{4-(quinolin-3-yl)-3-(trifluoromethyl)-1H-pyrazolo[3,4-b]pyridin-1-yl}benzonitrile instead of compound (1f).
