Benzyl chloroformate → (S)-2-(((Benzyloxy)carbonyl)amino)-3-cyclohexylpropanoic acid

To a solution of 3-cyclohexylalanine, hydrochloride (4.75 , 22.8 mmol) in 2N sodium hydroxide (11.4 mL) were added at 0° C., simultaneously, a solution of benzylchloroformate (3.2 mL, 36 mmol) in tetrahydrofuran (10 mL) and 2N sodium hydroxide (11.4 mL). (The pH of the mixture was maintained around 9-10 by addition of 2N sodium hydroxide.) The mixture was stirred for 1.5 hours. The solution was washed with diethyl ether (3×20 mL). The aqueous phase was acidified to pH 2 with 3N aqueous hydrochloric acid and extracted with ethyl acetate (3×50 mL). The combined organic layers were dried over anhydrous magnesium sulphate. Filtration and removal of the solvent in vacuo left 4.80 g of the expected product (yellow oil, 69% yield).

1. washThe solution was washed with diethyl ether (3×20 mL)
2. extractionextracted with ethyl acetate (3×50 mL)
3. dry with materialThe combined organic layers were dried over anhydrous magnesium sulphate
4. filtrationFiltration and removal of the solvent in vacuo

ORD-Eintrag

ord-e8614defd3404469aeb8615cf4130cb7

Quelldatensatz

uspto-grants-1992_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05114927