反应详情

温度

55 °C

A mixture of 7-bromo-2-methyl-2H-indazole-3-carboxylic acid methyl ester (35a; 0.215 g, 0.799 mmol), 8 mL of a 2 M aqueous NaOH solution, and 6 mL of ethanol was stirred at 55° C. overnight, then concentrated to remove ethanol. The remaining aqueous layer was acidified with a 10% aqueous HCl solution and extracted with three 20 mL portions of ethyl acetate. The combined organic layers were dried over Na2SO4, filtered, and concentrated to afford crude 7-bromo-2-methyl-2H-indazole-3-carboxylic acid (35e; 0.193 g; 94%) which was used without further purification.

1. concentrationconcentrated
2. customto remove ethanol
3. extractionextracted with three 20 mL portions of ethyl acetate
4. dry with materialThe combined organic layers were dried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated