1345121-23-4

1345121-19-8

1345121-23-4

General procedure for the synthesis of 6-bromo-5-methylpyrazolo[1,5-a]pyridine-3-carboxylic acid methyl ester from 6-bromo-5-methylpyrazolo[1,5-a]pyridine: firstly, 6-bromo-5-methyl-8-hydropyrazolo[1,5-a]pyridine (207A) was prepared; this was done as follows: 6-bromo-5-methyl-8-hydropyrazolo[1,5-a]pyridine-3- formate (206A, 79.6 mg, 0.3 mmol) was dissolved in 3 mL of 50% (v/v) sulfuric acid solution and heated at 85 °C for 3 min, followed by reaction at 60 °C for 4 days. Upon completion of the reaction, the mixture was cooled to room temperature, diluted with water, and sequentially neutralized with 1N NaOH and saturated aqueous NaHCO3 to pH=9. The reaction mixture was extracted with ethyl acetate (EA), the organic phase was washed with brine, dried over anhydrous sodium sulfate, and concentrated to dryness to yield 51mg of 207A (Yield: 64%, Purity >80%) as a brown solid, which can be used for subsequent reactions without further This product can be used in the subsequent reaction without further purification.