Triethylamine → tert-butyl 4-((5-bromo-1-isopropyl-1H-pyrazol-4-yl)methyl)-4-isocyanatopiperidine-1-carboxylate

Participants

Reaction Steps

A mixture of 4-((5-bromo-1-isopropyl-1H-pyrazol-4-yl)methyl)-1-(tert-butoxycarbonyl)piperidine-4-carboxylic acid (2.54 g, 5.9 mmol), diphenylphosphoryl azide (1.79 g, 6.5 mmol) and triethylamine (0.91 mL, 6.5 mmol) in toluene (15 mL) was heated at reflux for 3 hours. The mixture was then cooled to room temperature and the solvent removed in vacuo. The crude product was purified by column chromatography to give tert-butyl 4-((5-bromo-1-isopropyl-1H-pyrazol-4-yl)methyl)-4-isocyanatopiperidine-1-carboxylate (2.8 g, 100%). 1H NMR (300 MHz, CDCl3, δ): 7.47 (s, 1H), 4.68 (m, 1H), 3.99 (m, 2H), 2.95 (m, 2H), 2.67 (s, 2H), 1.62 (m, 4H), 1.45 (m, 15H).

Provenance & Evidence