2-Methylpyrazolo[1,5-a]pyriMidine-6-carboxylic acid synthesis

Yield:739364-95-5 76.7%

Reaction Conditions:

with sodium chlorite;dihydrogen peroxide in water at 50; for 1 h;Reagent/catalyst;Temperature;Solvent;

Steps:

10-14 Preparation of 2-methyl-pyrazolo[1,5-a]pyrimidine-6-carboxylic acid (VI)
Add 100 ml of water to a 500 mL four-necked flask equipped with a mechanical stirrer and a thermometer.6-carbaldehyde-2-methyl-pyrazolo[1,5-a]pyrimidine (V)35.2g (0.22mol),30% hydrogen peroxide 41.9g (0.33mol), sodium chlorite 29.9g (0.33mol),The temperature was raised to 50 ° C for 1 hour, and the temperature was lowered to 20 ° C. TLC showed the reaction was complete.Adjust to the starch potassium iodide reagent with sodium sulfite without discoloration, adjust the pH to 2 to 3 with hydrochloric acid.Filtered, the solid was recrystallized from 200 ml of ethanol.Obtained 29.8 g of 2-methyl-pyrazolo[1,5-a]pyrimidine-6-carboxylic acid (VI) as a white solid.The yield was 76.7%.In the present embodiment, the amount of hydrogen peroxide is the molar amount of the compound V: 150%.In the present embodiment, the amount of sodium chlorite used is the molar amount of the compound V: 150%.

References:

Hangzhou Hankang Bio-pharmaceutical Technology Co., Ltd.;Xiong Yi;Liu Ya CN110003218, 2019, A Location in patent:Paragraph 0069-0096

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