Pentanenitrile, 4,4-dimethyl-3-oxo- → 3-Tert-butyl-1-(2,4-dimethylphenyl)-1H-pyrazol-5-amine
Reaction equation
Cl.[CH3:2][C:3]1[CH:8]=[C:7]([CH3:9])[CH:6]=[CH:5][C:4]=1[NH:10][NH2:11].[CH3:12][C:13]([CH3:20])([CH3:19])[C:14](=O)[CH2:15][C:16]#[N:17]>CCO.O>[C:13]([C:14]1[CH:15]=[C:16]([NH2:17])[N:10]([C:4]2[CH:5]=[CH:6][C:7]([CH3:9])=[CH:8][C:3]=2[CH3:2])[N:11]=1)([CH3:20])([CH3:19])[CH3:12]Participants
4
Procedure
To a heated solution of 2,4-dimethylphenylhydrazine hydrochloride (1.38 g, 8 mmol) in EtOH/water/1M NaOH (20 mL/12 mL/8 mL) at 50° C., 4,4-dimethyl-3-oxopentanenitrile (1.0 g, 8 mmol) was added and the reaction heated until finished by LC-MS. The solution was partitioned between EtOAc and water, and extracted twice. The extracts were washed with brine, dried with magnesium sulfate, filtered, and concentrated. Purification using silica gel chromatography eluting with an EtOAC/hexane gradient (5-20%) gave 3-tert-butyl-1-(2,4-dimethylphenyl)-1H-pyrazol-5-amine (700 mg, 36% yield). 1H NMR (300 MHz, DMSO d6) δ 1.09 (s, 9H), 1.98 (s, 3H), 2.32 (s, 3H), 4.76 (s, 2H), 5.26 (s, 1H), 7.11 (m, 3H). LC-MS (ESI) m/z 244 (M+H)+.