Borane → ((S)-4,5-Diamino-pentyl)-carbamic acid benzyl ester

Temperature

10 °C

((S)-4-Amino-4-carbamoyl-butyl)-carbamic acid benzyl ester (1.87 g, 7.071 mmol) is suspended in dry THF (40 ml) and cooled to 10° C. in an ice bath under nitrogen. Borane (28.3 ml of a 1 M solution in THF, 28.3 mmol) is added. The ice bath is removed and the suspension heated to 70° C. and then left to stir at this temperature for 3 hours. Further borane (28.3 ml of a 1 M solution in THF, 28.3 mmol) is added and then after an hour the same amount of 1M borane in THF is added again. After a final hour at 70° C. the reaction mixture is quenched with MeOH (40 ml). The solvent is reduced in vacuo to approximately 50 ml. This is diluted with 5 M HCl (100 ml) and washed with diethyl ether (3×100 ml). The aqueous phase is basified to pH12 with 2N NaOH and product extracted into EtOAc (3×100 ml). The organic phases are combined, dried over MgSO4 and the solvent evaporated in vacuo to yield the title compound as a colourless oil.

1. customThe ice bath is removed
2. temperaturethe suspension heated to 70° C.
3. waitleft
4. additionFurther borane (28.3 ml of a 1 M solution in THF, 28.3 mmol) is added
5. additionafter an hour the same amount of 1M borane in THF is added again
6. customAfter a final hour at 70° C. the reaction mixture is quenched with MeOH (40 ml)
7. additionThis is diluted with 5 M HCl (100 ml)
8. washwashed with diethyl ether (3×100 ml)
9. extractionextracted into EtOAc (3×100 ml)
10. dry with materialdried over MgSO4
11. customthe solvent evaporated in vacuo

ORD record

ord-f19a1d32b70444b99f421e5317b7ce37

Source dataset

uspto-grants-2011_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08039472B2