1,2-Dichloroethane → HCID 54414223, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 4,4-difluoro-pyrrolidine-1,2-dicarboxylic acid-1-benzyl ester-2-tert-butyl ester (113) (Karanewsky, et. al., J. Med. Chem. 33, pp. 1459-1469 (1990)) (0.42 g, 1.23 mmol) and 10% palladium on carbon (0.22 g) in methanol (6 mL) was stirred at 1 atm hydrogen pressure for 3 h. The mixture was filtered through Celite and evaporated. The residue was dissolved in CH2Cl2 (4 mL) and DMF (2 mL) and cooled to 0° C. 2-Benzyloxycarbonylamino-propionic acid (0.30 g, 1.35 mmol), EDC (0.30, 1.54 mmol), DIEA (0.65 mL) and HOBt (0.17 g, 1.23 mmol) was added and the reaction was stirred 0.5 h at 0° C., then 16 h at room temperature under nitrogen. The solvent was removed in vacuo and the residue was dissolved in ethyl acetate, then was washed with 10% sodium bisulfate, saturated sodium bicarbonate, water and brine, was dried over sodium sulfate and was evaporated. Purification by flash chromatography on silica, eluted with 25:75 ethyl acetate:hexanes provided 1-(2-benzyloxycarbonylamino-propionyl)-4,4-difluoro-pyrrolidine-2-carboxylic acid tert-butyl ester (0.39 g, 77% yield) as a colorless oil.

Provenance & Evidence