p-Xylyl bromide → 1-(4-methylbenzyl)-3-nitro-1H-pyrazole

Beteiligte Stoffe

Reaktionsschritte

To a solution of 3-nitro-1H-pyrazole (prepared in example 3, 200 mg, 1.77 mmol) in anhydrous N,N-dimethylformamide (2 mL), a 60% dispersion of sodium hydride in mineral oil 92 mg, 2.30 mmol) was added while stirring under nitrogen. After the effervescence ceased and the mixture was stirred for additional 20 min, 4-methylbenzylbromide (426 mg, 2.30 mmol) was added. The mixture was continued to stir under nitrogen for an additional 2 h. The solvent was removed in vacuo and purification by ISCO flash column chromatography (Teledyne Isco RediSep Flash Column 40 g; 2% methanol/methylene chloride to 5% methanol/methylene chloride) afforded 1-(4-methyl-benzyl)-3-nitro-1H-pyrazole (316 mg, 82%) as a white solid: H1-NMR (400 MHz, CDCl3) δ: 2.36 (3H, s), 5.32 (2H, s), 6.87 (1H, d, J=2.3 Hz), 7.19 (4H, s), 7.34 (1H, d, J=2.3 Hz).

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