To a solution of 2,5-dimethyl-1,3-thiazole-4-carboxylic acid (107 mg, 0.681 mmol) in tetrahydrofuran (5 mL) were added N,N-dimethylformamide (2 drops) and thionyl chloride (118 μL, 1.36 mmol), and the mixture was stirred at room temperature for 2 hr. The reaction mixture was concentrated under reduced pressure, and the residue was dissolved in N,N-dimethylacetamide (6 mL). N-[6-(3-Amino-4-methylphenoxy)[1,2,4]triazolo[1,5-a]pyridin-2-yl]cyclopropanecarboxamide (200 mg, 0.619 mmol) was added thereto, and the mixture was stirred at room temperature for 2 hr. The reaction mixture was diluted with saturated aqueous sodium hydrogen carbonate solution, and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous magnesium sulfate and filtrated. The filtrate was concentrated under reduced pressure, the residue was and recrystallized from ethanol to give the title compound (248 mg, 87%) as a white solid.
