3-Bromophenylhydrazine hydrochloride → 1-(3-Bromophenyl)-3-(tert-butyl)-1H-pyrazol-5-amine

Participants

Reaction Steps

A mixture of 3-bromophenylhydrazine hydrochloride (5.00 g, 22.4 mmol) and 4,4-dimethyl-3-oxo-pentanenitrile (4.29 g, 33.6 mmol) in absolute ethanol (55 mL) was stirred at reflux for 18 h and cooled, then concentrated in vacuo. The residue was suspended in sat. aq. NaHCO3 (50 mL) and extracted with EtOAc (3×50 mL). The combined organics were dried (Na2SO4) and concentrated in vacuo. The residue was purified by FCC, using 0-5% [2M NH3 in MeOH] in DCM, to give the title compound (3.56 g, 54%). LCMS (Method 1): Rt 3.33 min, m/z 294, 296 [MH+].

Provenance & Evidence