反应详情

To a mixture of 3.4 g (17.78 mmol) of 6-amino-1H-indazole-7-carboxylic acid methyl ester, prepared as in step a in example 10, in 34 mL of N,N-dimethylformamide is added 3.16 g (17.78 mmol) of N-bromosuccinimide. The reaction is stirred at ambient temperature 4 hours. After concentration in vacuo the residue is triturated in ethyl acetate and after filtration 3.38 g of a brownish solid are obtained. The filtrate is evaporated and submitted to column chromatography purification on silica gel with hexanes and ethyl acetate as eluents to afford 563 mg of a white solid. In totality 3.95 g (82%) of a product are obtained; LC/MS:270/272 (M+H)+.

1. concentrationAfter concentration in vacuo the residue
2. customis triturated in ethyl acetate
3. filtrationafter filtration 3.38 g of a brownish solid
4. customare obtained
5. customThe filtrate is evaporated
6. customsubmitted to column chromatography purification on silica gel with hexanes and ethyl acetate as eluents