Hydrazine hydrate (1:1) → 3-(3-chlorophenyl)-1H-pyrazol-5-amine

Participants

Reaction Conditions

Reaction Steps

To a stirring solution of 3-(3-chlorophenyl)-3-oxo-propionitrile (2 g, 11.1 mmol) in absolute ethanol (20 mL) was added hydrazine hydrate (3.24 mL, 67 mmol). The reaction mixture was stirred at 80° C. for 15 h, cooled to room temperature, concentrated in vacuo, and absorbed on silica gel. Purification on silica gel with 0-10% MeOH in CH2Cl2 as eluent provided 1.53 g (70%) of 5-(3-chloro-phenyl)-2H-pyrazol-3-ylamine as a green solid. 1H NMR (d6-DMSO) δ: 11.6 and 11.9 (2 broad s, 1H, NH+tautomer), 7.69 (s, 1H), 7.60 (d, 1H), 7.38 (t, 1H), 7.29 (d, 1H), 5.77 (broad s, 1H), 4.98 (broad s, 2H, NH2).

Provenance & Evidence