Triethylamine → 4-(2,5-Dichloro-pyridin-4-ylethynyl)-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Copper(I) iodide (0.50 g), bis-(triphenylphosphine)-palladium(II) chloride (0.50 g), and triethylamine (3.4 mL) are added successively to a solution of 2,5-dichloro-4-iodo-pyridine (6.54 g) in N,N-dimethylformamide (45 mL) under Ar atmosphere at room temperature. The resulting mixture is stirred at room temperature for 1 h prior to the addition of 4-ethynyl-piperidine-1-carboxylic acid tert-butyl ester (5.15 g). The mixture is stirred at 55° C. for 2 h. The solvent is evaporated and the residue is diluted with ethyl acetate. The resulting mixture is washed with water and brine, dried (Na2SO4), and concentrated. The residue is chromatographed on silica gel (cyclohexane/ethyl acetate 85:15→50:50) to give the title compound. LC (method 3): tR=1.66 min; Mass spectrum (ESI+): m/z=355/357/359 (2 Cl) [M+H]+.

Provenance & Evidence