反应详情

670 mg of a mixture of methyl 1-methyl-6-nitro-1H-indazole-3-carboxylate and methyl 2-methyl-6-nitro-2H-indazole-3-carboxylate (Example XX) are dissolved in 20 ml of ethanol, combined with 10 ml 1 M sodium hydroxide solution and stirred for 2 hours. Then 10 ml of 1 M hydrochloric acid are added, the mixture is diluted with water and the precipitated solid is suction filtered. Then the solid is dissolved in dichloromethane/methanol 90:10. After drying with magnesium sulphate the solvents are eliminated in vacuo and the residue is dried in vacuo. 640 mg of a mixture of 1-methyl-6-nitro-1H-indazole-3-carboxylic acid and 2-methyl-6-nitro-2H-indazole-3-carboxylic acid is obtained which is further reacted directly in Example XV (1) or in XV (2), respectively.

1. filtrationfiltered
2. dissolutionThen the solid is dissolved in dichloromethane/methanol 90:10
3. dry with materialAfter drying with magnesium sulphate the solvents
4. customthe residue is dried in vacuo