Triphenylphosphine → 5-(1-azido-2-ethylbutyl)-1-[(4-methylphenyl)sulfonyl]-1H-pyrazole

Participants

Reaction Steps

To 2-ethyl-1-{1-[(4-methylphenyl)sulfonyl]-1H-pyrazol-5-yl}butan-1-ol (0.250 g, 0.778 mmol) in THF (10 mL) at 0° C. was added triphenylphosphine (0.307 g, 1.17 mmol), diethyl azodicarboxylate (0.18 mL, 1.2 mmol), and diphenylphosphoryl azide (0.25 mL, 1.2 mmol). The reaction mixture was warmed to room temperature and stirred for 20 h. The solvent was removed in vacuo and the resulting residue was purified by column chromatography (EtOAc/hexanes, 15:85) to give 0.260 g (97%) of 5-(1-azido-2-ethylbutyl)-1-[(4-methylphenyl)sulfonyl]-1H-pyrazole with an aromatic impurity as judged by 1H NMR. This compound was used in the next step without further purification.

Provenance & Evidence