739364-95-5

338953-49-4

739364-95-5

The general procedure for the synthesis of 2-methylpyrazolo[1,5-a]pyrimidine-6-carboxylic acid, using the compound (CAS: 338953-49-4) as a starting material, was as follows (Intermediate Example 16): 2-methylpyrazolo[1,5-a]pyrimidine-6-carboxylic acid amide (475 mg) was dissolved in ethanol (5 mL), and a 5 N sodium hydroxide solution was subsequently added to the solution (2 mL). The reaction mixture was stirred at 70 °C for 1 hour. After completion of the reaction, the mixture was cooled to room temperature, an appropriate amount of water was added and the reaction mixture was washed with ethyl acetate. After separating the aqueous phase, 2 N hydrochloric acid was added dropwise until the pH became acidic. The precipitated white crystals were collected by filtration and washed sequentially with water and hexane. Finally, the resulting crystals were dried under reduced pressure to afford the target product 2-methylpyrazolo[1,5-a]pyrimidine-6-carboxylic acid (300 mg, yield: 63%). Product mass spectral data: ESI/MS m/z 178 ([M+H]+), 176 ([M-H]-).