Pyridine → (R)-4-Chlorocarbonyl-3-ethyl-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

Bis-(trichloromethyl)-carbonate (13.9 g, 47 mM) was dissolved in dichloromethane (500 mL) and cooled to 0° C. A mixture of (R)-3-ethyl-piperazine-1-carboxylic acid tert-butyl ester (26.5 g; 0.124 M) and pyridine (10.9 mL, 0.136 M) in dichloromethane (150 mL) was added dropwise with stirring (0–3° C.). Stirring was continued for another ½ h at room temperature. The mixture was washed with water and brine, the water phases were extracted with dichloromethane, organic phases were pooled, dried with Na2SO4 and evaporated to yield a brown oil (34 g, 99%) which crystallized upon standing; MS (EI): 276.2 (M)+.

Provenance & Evidence