Cyclohexylamine → (S)-Benzyl (1-(cyclohexylamino)-3-methyl-1-oxobutan-2-yl)carbamate

Temperature

0 °C

A solution of carbobenzoxy-(S)-valine (1.26 g, 5 mmol) in anhydrous THF (20 ml) was vigorously stirred and thereto were added triethylamine (0.70 ml, 5 mmol) and isobutyl chloroformate (0.66 ml, 5 mmol) at 0° C. To this mixture was added cyclohexylamine (0.57 ml, 5 mmol) and this mixture was stirred for 2 hours at 0° C. and further for 24 hours at room temperature. The solvent was removed to obtain white crystals. These crystals were dissolved in a mixture of CH2Cl2 (80 ml) and water (30 ml). The organic layer was washed with 0.5M boric acid, a saturated aqueous sodium chloride solution, a saturated aqueous sodium hydrogencarbonate solution, a saturated aqueous sodium chloride solution and water (50 ml each) in succession, dried over Na2SO4 and concentrated under reduced pressure to obtain crude carbobenzoxy-(S)-valine cyclohexylamide (1.45 g, 87%), which was used as it was for the following reaction.

1. customThe solvent was removed
2. customto obtain white crystals
3. washThe organic layer was washed with 0.5M boric acid
4. dry with materiala saturated aqueous sodium chloride solution, a saturated aqueous sodium hydrogencarbonate solution, a saturated aqueous sodium chloride solution and water (50 ml each) in succession, dried over Na2SO4
5. concentrationconcentrated under reduced pressure

ORD record

ord-70ddc02ac51c4a66aff94eb7b92af1f5

Source dataset

uspto-grants-1994_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05308820