Potassium Iodide → ethyl 1-benzyl-3-nitro-1H-pyrazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of C1 (2.86 g, 15.4 mmol) in N,N-dimethylformamide (60 mL) was added anhydrous potassium carbonate (12.8 g, 92.6 mmol), benzyl bromide (2.20 mL, 18.5 mmol) and a catalytic amount of potassium iodide. The reaction was heated at 60° C. for 18 hours, then diluted with EtOAc and washed with water. The organic layer was dried over magnesium sulfate, filtered and concentrated under reduced pressure. Purification using silica gel chromatography (Gradient: 0% to 100% EtOAc in heptane) provided C2 as an oil. Yield: 1.35 g, 4.90 mmol, 32%. An NOE experiment revealed a strong interaction between the pyrazole CH and aromatic protons on the phenyl group, supporting the indicated regiochemistry for C2. LCMS m/z 276.0 (M+1). 1H NMR (400 MHz, CDCl3) δ 1.32 (t, J=7.1 Hz, 3H), 4.31 (q, J=7.1 Hz, 2H), 5.33 (s, 2H), 7.30-7.35 (m, 2H), 7.40-7.45 (m, 3H), 7.78 (s, 1H).

Provenance & Evidence