Dicyclohexylcarbodiimide → (S)-Benzyl 2-(dimethylcarbamoyl)pyrrolidine-1-carboxylate

Participants

Reaction Steps

In 80 ml of dry THF were dissolved 4.9 g (20 m mol) of N-benzyloxycarbonyl-L-proline (29) and 3.5 g (26 m mole) of HOBT and then 4.53 g (22 m mol) of DCC was slowly added to the solution at 0° C. After stirring the mixture for 30 minutes at the same temperature, 10 ml of solution 2M dimethylamine tetrahydrofuran was added. The resulting mixture was allowed to stand for 12 hours at room temperature. THF was distilled off from the reaction mixture under reduced pressure, the residue thus formed was dissolved in 200 ml of ethyl acetate, and the solution was washed, in succesion, with 75 ml of an aqueous solution of 0.5N hydrochloric acid, 75 ml of a saturated aqueous sodium hydrogencarbonate solution, and 50 ml of water. After drying the organic layer with anhydrous magnesium sulfate, ethyl acetate was distilled off and the residue thus formed was purified by silica gel column chromatography (400 ml of Wako gel C-200, ethyl acetate) to provide 4.8 g of (S)-1-benzyloxycarbonyl-N,N-dimethyl-2-pyrrolidinecarboxamide (88) having a melting point of 66°-67° C.

Provenance & Evidence