Sodium hydride → 4-(3-Nitro-pyrazol-1-ylmethyl)-cyclohexanecarboxylic acid methyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

The 3-Nitro-1H-pyrazole (prepared in example 3, 130 mg, 1.16 mmol) was dissolved in N,N-dimethylformamide (4 mL) and a 60% suspension of sodium hydride in mineral oil (50 mg, 1.25 mmol) was added. After the effervescence ceased and the reaction stirred for an additional 10 min, the 4-(toluene-4-sulfonyloxymethyl)-cyclohexanecarboxylic acid methyl ester (380 mg, 1.16 mmol) was added and the reaction was heated to 80° C. while stirring for 4 h. The reaction continued to stir under nitrogen for 2 h. The solution was diluted with ethyl acetate (100 mL), washed with saturated aqueous sodium bicarbonate solution (35 mL), 1.0 M aqueous hydrochloric acid solution (35 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. Purification by flash column chromatography (Merck silica gel 60, 40-63 μm; 5% ethyl acetate/hexanes to 50% ethyl acetate/hexanes) afforded 4-(3-nitro-pyrazol-1-ylmethyl)-cyclohexanecarboxylic acid methyl ester (114 mg, 37%) as a yellow oil: H1-NMR (400 MHz, CDCl3) δ 1.00-1.12 (2H, m), 1.36-1.50 (2H, m), 1.68-1.78 (2H, m), 1.90-2.08 (3H, m), 2.20-2.30 (1H, m), 3.66 (3H, s), 4.03 (2H, d, J=7.2 Hz), 6.88 (2H, d, J=2.4 Hz), 7.40 (2H, d, J=8.4 Hz).

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