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

Participants

Reaction Steps

A 250-mL Parr reactor bottle was purged with nitrogen and charged with 10% palladium on carbon (50% wet, 150 mg dry weight) and a solution of 119a (1.02 g, 3.76 mmol) in ethanol (20 mL). The bottle was attached to a Parr hydrogenator, evacuated, charged with hydrogen gas to a pressure of 50 psi and shaken for 3 h. After this time, the hydrogen was evacuated, and nitrogen was charged into the bottle. Celite 521 (1.00 g) was added, and the mixture was filtered through a pad of Celite 521. The filter cake was washed with ethanol (2×25 mL), and the combined filtrates were concentrated to dryness under reduced pressure to afford a 100% yield (928 mg) of 119b as a white solid: mp 54-55° C.; 1H NMR (500 MHz, CDCl3) δ 7.25 (d, 1H, J=2.0 Hz), 5.36 (d, 1H, J=2.0 Hz), 4.54 (br s, 2H), 3.90 (t, 2H, J=5.5 Hz), 3.81 (t, 2H, J=5.5 Hz), 0.84 (s, 9H), −0.35 (s, 6H). MS (APCI+) m/z 242.6 (M+H).

Provenance & Evidence