Sodium borohydride → methyl 4-amino-1H-indazole-1-carboxylate

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Reaction Steps

The product of Example 90A (1.66 g, 7.5 mmol) in ethanol (20 mL) was treated with BiCl3 (8.2 g, 2.6 mmol) followed by the addition of NaBH4 (1.13 g, 30.5 mmol). The reaction mixture was stirred at room temperature for 20 minutes, filtered through Celite, and the filtrate was evaporated under reduced pressure. The residue was partitioned between ethyl acetate/dilute NaHCO3 solution. The organic phase was separated, dried over MgSO4, filtered and the filtrate concentrated under reduced pressure to provide the title compound (1.2 g). 1H NMR (300 MHz, DMSO-d6) δ 6.1 (s, 2H), 6.41 (dd, 1H), 7.21 (m, 2H), 8.42 (s, 1H).

Provenance & Evidence