To a solution of 6-amino-1H-pyrrolo[2,3-b]pyridine-5-carboxylic acid ethyl ester described in Preparation Example R-2 (95 mg, 0.46 mmol) in ethanol (10 mL) was added an aqueous solution of 1N sodium hydroxide (5 mL, 5 mmol), which was then heated for 3 hours in an oil bath at 98° C. After cooling the reaction solution, the reaction solution was concentrated until it reached ⅓ of its volume, neutralized with 1N hydrochloric acid, and further concentrated. The resulting crude product was suspended in N,N-dimethylformamide (5 mL), triethylamine (0.096 mL, 0.69 mmol), benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (153 mg, 0.35 mmol) and C-(5-phenoxy-thiophen-2-yl)-methylamine described in Preparation Example 26 (71 mg, 0.35 mmol) were added thereto, followed by stirring at room temperature for 15 hours. After the reaction was completed, the reaction solution was poured into brine, and extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate, then concentrated, the obtained residue was purified by silica gel column chromatography (ethyl acetate:hexane=2:1), and the title compound (31 mg, 0.085 mmol, 18.5%) was obtained.
