Hydrazine hydrate (1:1) → 3-amino-1H-indazole-5-carboxylic Acid

Participants

Reaction Steps

To a solution of 3-cyano-4-fluorobenzoic acid (980.0 mg, 5.94 mmol) in ethanol (6 mL), was added hydrazine hydrate (0.89 mL, 17.8 mmol). The reaction was heated at reflux for 3 hours. The reaction was cooled to room temperature and ethanol was removed under reduced pressure. The resultant yellow oil was taken up in water (50 mL) and basified with 1 N aqueous sodium hydroxide (5 mL). The solution was washed once with ethyl acetate (25 mL). The aqueous phase was acidified to pH=3 with 6 N aqueous hydrochloric acid and was allowed to stir at room temperature for 1 hour. The resulting precipitate was collected by filtration and dried under vacuum to give the title compound (612 mg, 48%) as a pink solid. +ESI (M+H) 178.1; 1H NMR (400 MHz, DMSO-d6, δ): 8.42-8.47 (m, 1H), 7.76 (dd, J=8.8, 1.6 Hz, 1H), 7.21 (d, J=8.8 Hz, 1H).

Provenance & Evidence