7-Nitroindazole → tert-Butyl 7-nitro-1H-indazole-1-carboxylate

Beteiligte Stoffe

Reaktionsschritte

A solution of 7-nitro-1H-indazole (2.81 g, 17.23 mmol), di-tertbutyl carbonate (7.52 g, 34.5 mmol), triethylamine (4.81 mL, 34.5 mmol) and 4-dimethylamino-pyridine (2.11 g, 17.2 mmol) in anhydrous acetonitrile (100 mL) is stirred under nitrogen at ambient temperature for approximately 3 hrs. After removing the solvent in vacuo, the residue is partitioned between ethyl acetate and aqueous sodium hydrogen sulfate (1N). The organic layer is separated, washed with saturated aqueous brine, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo. The crude product is purified by chromatography on flash grade silica gel using DCM. Fractions containing the product are combined, concentrated in vacuo to a solid and dried under high vacuum to provide the title compound as a yellow solid (2.674 g, 10.16 mmol). 1H NMR (300 MHz, d6-DMSO) δ=1.55 (s, 9H); 7.58 (t, J=8.0 Hz, 1H); 8.20 (d, J=7.4 Hz, 1H); 8.30 (d, J=7.7 Hz, 1H); 8.67 (s, 1H), TLC: Rf =0.5 (DCM).

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