Sodium hydride → 1-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3-nitro-1H-pyrazole

Participants

Reaction Steps

A solution of 3-nitro-1H-pyrazole (Intermediate 2, 250 mg, 2.21 mmol) was dissolved in anhydrous N,N-dimethylformamide (5 mL) was treated with a 60% dispersion of sodium hydride in mineral oil (93 mg, 2.32 mmol) was added while stirring under nitrogen. After the effervescence ceased, the reaction stirred for an additional 10 min. At this time, the reaction was treated with (2-bromo-ethoxy)-tert-butyl-dimethyl-silane (598 mg, 2.50 mmol). The reaction continued to stir under nitrogen for 2 h. At this time, the solution was diluted with ethyl acetate (200 mL), washed with water (2×75 mL), a saturated aqueous sodium chloride solution (75 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. Silica gel column chromatography (Merck silica gel 60, 40-63 μm; 5-25% ethyl acetate/hexanes) afforded 1-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3-nitro-1H-pyrazole (508 mg, 84%) as a yellow oil. 1H-NMR (400 MHz, DMSO-d6) δ 0.00 (6H, s), 0.86 (9H, s), 4.03 (2H, t, J=5.6 Hz), 4.40 (2H, t, J=5.2 Hz), 7.11 (1H, d, J=2.4 Hz), 8.06 (1H, d, J=2.4 Hz).

Provenance & Evidence