Hydrochloric Acid → HCID 57699991, compound

Temperature

-20 °C

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%).

1. customThe reaction mixture became very thick with precipitation of a white solid
2. additionThe reaction was therefore diluted further with THF (100 ml)
3. additionto aid mixing
4. waitleft
5. filtrationThe precipitated mass was filtered off
6. stirringto stir to room temperature
7. waitleft for 4 hours for complete reaction
8. customthe THF removed under reduced pressure
9. extractionThe aqueous solution was extracted with EtOAc (3×100 ml)
10. dry with materialdried over magnesium sulphate
11. customThe product was purified by column chromatography (DCM-5% MeOH/DCM)

ORD record

ord-3be8a66ce4ba47c99e98b13049bc43dc

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08106091B2