Hydrochloric Acid → 1-methyl-3-(trifluoromethyl)-1H-pyrazol-5-amine

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Reaction Steps

A solution of methylhydrazine (5.0 g, 60 mmol) and 4,4,4-trifluoro-3-oxo-butyronitrile (9.8 g, 71 mmol) in EtOH (50 mL) was treated with conc. HCl (5 mL) and the resultant mixture was heated to reflux overnight. The solvent was removed in vacuo and the crude product was dissolved in EtOAc washed with saturated aq. Na2CO3 solution until the washings were pH 8. The organics were concentrated and purified by prep-HPLC to provide 2-methyl-5-trifluoromethyl-2H-pyrazol-3-ylamine (2.07 g, 21% yield). 1H NMR (300 MHz, DMSO-d6), δ 5.57 (s, 1 H), 5.54 (br s, 2 H), 3.55 (s, 3 H); MS (ESI) m/z: 166.1 (M+H+).

Provenance & Evidence