Tert-butyl 3-tert-butoxycarbonylamino-6-ethoxy-7-fluoro-5-nitroindazole-1-carboxylate → Tert-butyl 5-amino-3-tert-butoxycarbonylamino-6-ethoxy-7-fluoroindazole-1-carboxylate

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Reaction Steps

4.2 2.50 g of tert-butyl 3-tert-butoxycarbonylamino-6-ethoxy-7-fluoro-5-nitroindazole-1-carboxylate are hydrogenated in 20 ml of methanol at RT (catalyst: Raney nickel 0.5 g, hydrogen uptake: 300 ml). The reaction batch is filtered and evaporated. Purification of the residue by column chromatography on silica gel (eluent: petroleum ether: ethyl acetate 7:3) gives 3.30 g (36%) of tert-butyl 5-amino-3-tert-butoxycarbonylamino-6-ethoxy-7-fluoroindazole-1-carboxylate, MS-FAB (M+H+)=441.

Provenance & Evidence