Hydrochloric Acid → HCID 57699991, compound

Participants

Reaction Conditions

Reaction Steps

Ethyl chloroformate (2.45 ml, 25.6 mmol, 1.2 eq) was added at −20° C. to a stirred solution of (S)-2-tert-butoxycarbonylamino-pentanedioic acid 1-cyclopentyl ester (6.73 g, 21.4 mmol) and N-methyl morpholine (3.05 ml, 27.8 mmol, 1.3 eq) in THF (50 ml). The reaction mixture became very thick with precipitation of a white solid. The reaction was therefore diluted further with THF (100 ml) to aid mixing and left stirring at −20° C. for 2 hours. The precipitated mass was filtered off and the filtrate was added over a period of 20 minutes to a solution of sodium borohydride (2.43 g, 64.1 mmol, 3 eq) in THF (20 ml) and water (5 ml) at 0° C. The reaction mixture was allowed to stir to room temperature and left for 4 hours for complete reaction. The mixture was acidified to pH 5 with 1M HCl and the THF removed under reduced pressure. The aqueous solution was extracted with EtOAc (3×100 ml) and dried over magnesium sulphate. The product was purified by column chromatography (DCM-5% MeOH/DCM) and isolated as a clear oil (5.0 g, 78%).

Provenance & Evidence