Sodium hydride → [3-(3-Nitro-pyrazol-1-ylmethyl)-phenyl]-carbamic acid tert-butyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

3-Nitro-1H-pyrazole (prepared in example 3, 595 mg, 5.26 mmol) was dissolved in anhydrous N,N-dimethylformamide (10 mL) and a 60% dispersion of sodium hydride in mineral oil (211 mg, 5.28 mmol) was added while stirring under nitrogen. After the effervescence ceased and the reaction stirred for an additional 25 min, the reaction was chilled to 0° C. and (3-bromomethyl-phenyl)-carbamic acid tert-butyl ester (1.50 g, 5.26 mmol) was added. The reaction continued to stir under nitrogen at 0° C. for 20 min. The reaction was diluted with ethyl acetate (200 mL), washed with water (2×50 mL), saturated aqueous brine solution (2×20 mL), dried over magnesium sulfate and concentrated in vacuo to give a yellow oil. Purification by flash column (Merck silica gel 60, 40-63 μm; 15% ethyl acetate/hexanes) followed by recrystallization from methylene chloride afforded [3-(3-nitro-pyrazol-1-ylmethyl)-phenyl]-carbamic acid tert-butyl ester (782 mg, 47%) as a beige solid: H1-NMR (400 MHz, DMSO-d6) δ 1.45 (9H, s), 5.39 (2H, s), 6.88 (1H, d, J=7.6 Hz), 7.06 (1H, d, J=2.4 Hz), 7.22 (1H, t, J=8.0 Hz), 7.35 (1H, d, J=8.0 Hz), 7.40 (1H, s), 8.11 (1H, d, J=2.8 Hz), 9.36 (1H, s).

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