Pyrazole → HCID 43381460, compound

Participants

Reaction Steps

General procedure for pyrazole formation: An ethanolic solution (3 mL) of 4-methoxybenzoylacetonitrile (500 mg, 2.85 mmol), t-butylhydrazine hydrochloride (391 mg, 3.14 mmol), and catalyticp-toluenesulfonic acid was stirred under argon at 90° C. for 4 h in a sealed tube. The reaction was concentrated and the residue partitioned between EtOAc and sat. NaHCO3. The organic layer was washed with brine, dried with Na2SO4, filtered and concentrated in vacuo. The residue was chromatographed on silica gel with a gradient of 10-30% EtOAc in Hexanes which yielded 2-tert-Butyl-5-(4-methoxyphenyl)-2H-pyrazol-3-ylamine: 1H NMR (400 MHz, CDCl3) δ 1.70 (s, 9H), 3.58 (br.s, 2H), 3.84 (s, 3H), 5.85 (s, 1H), 6.91 (d, J=8.8 Hz, 2H), 7.69 (d, J=8.8 Hz, 2H); MS (ES+): m/z 246 [MH+], m/z 190 [M-tbutyl].

Provenance & Evidence