Diisopropylamine → 4-[2-(2,5-Dichloro-pyrimidin-4-yl)-1-hydroxy-ethyl]-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

N-butyllithium (1.6 M in hexanes, 4.99 mL) is added drop wise to diisopropylamine (1.13 mL) in tetrahydrofuran (20 mL) at −50 to −60° C. under an argon atmosphere. The mixture is stirred for 30 min at this temperature, cooled to −70° C., and 2,5-dichloro-4-methyl-pyrimidine (1.00 g) is added. After 1 h a solution of 4-formyl-piperidine-1-carboxylic acid tert-butyl ester (1.37 g) in tetrahydrofuran (10 mL) is added and the resulting mixture is stirred for another hour. The reaction is quenched with acetic acid solution (1% in ethanol, 10 mL) and the mixture is diluted with ethyl acetate. The organic phase is separated, washed with water and aqueous NaHCO3 solution, dried over MgSO4, and concentrated in vacuo. The residue is chromatographed on silica gel (cyclohexane/ethyl acetate 75:25→30:70) to give the title compound. LC (method 7): tR=1.40 min; Mass spectrum (ESI+): m/z=376 [M+H]+.

Provenance & Evidence