反应详情

4-bromo-1H-pyrazole (362 mg), 1,8-diazabicyclo[5.4.0]undec-7-ene (0.368 ml) and tert-butyl 4-(cyanomethylene)piperidine-1-carboxylate (547 mg) in acetonitrile (10 ml) were stirred at 45° C. for 6 hours. The crude reaction was concentrated on dicalite (diatomaceous earth) and was purified by flash chromatography on silica gel eluting with 0 to 20% ethyl acetate in petroleum ether. The solvent was evaporated to dryness to afford tert-butyl 4-(4-bromopyrazol-1-yl)-4-(cyanomethyl)piperidine-1-carboxylate (570 mg) as a white foam. NMR Spectrum: (DMSO-d6) 1.45 (s, 9H), 1.94-2.04 (m, 2H), 2.54-2.62 (m, 2H), 2.80 (s, 2H), 2.93-3.04 (m, 2H), 3.88 (bs, 2H), 7.57 (s, 1H), 7.73 (s, 1H)

1. customThe crude reaction
2. concentrationwas concentrated on dicalite (diatomaceous earth)
3. customwas purified by flash chromatography on silica gel eluting with 0 to 20% ethyl acetate in petroleum ether
4. customThe solvent was evaporated to dryness