Triphenylphosphine → 4-[3-(3-Nitro-phenyl)-4-pyridin-4-yl-pyrazol-1-yl]-piperidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a suspension of 4-[3-(3-nitro-phenyl)-1H-pyrazol-4-yl]-pyridine (200 mg, 0.750 mmol) in anhydrous tetrahydrofuran (3 mL) at 0° C. triphenylphosphine (293 mg, 1.12 mmol, 1.5 eq), 4-hydroxy-piperidine-1-carboxylic acid tert-butyl ester (150 mg, 0.750 mmol, 1 eq) and DEAD (176 μL, 1.12 mmol, 1.5 eq) were added. The reaction was allowed to warm to room temperature and stirred under nitrogen atmosphere overnight. The regioisomeric ratio was 1:4 at 254 nm in favor of the N1-alkylated product. The solvent was removed under reduced pressure and the residue was purified by silica gel column chromatography (DCM/ethanol 97:3) to give 950 mg of major regioisomer contaminated with triphenylphosphinoxide.

Provenance & Evidence