Citric Acid → Cyclohexyl-(3-hydroxy-propyl)-carbamic acid tert-butyl ester

To a stirred solution of ethyl N-tert-butoxycarbonyl-3-cyclohexylamino-propanoate (2a, 2.18 9, 7.3 mmol) in tetrahydrofuran (20 mL) was added lithium aluminium hydride (1.0 M solution in tetrahydrofuran. 10 mL). The reaction mixture was stirred for 1 h, after which ethyl acetate (5 mL) was slowly added. Subsequently, aqueous citric acid (0.5 M, 50 mL) was added and the heterogeneous mixture was extracted with Et2O (2×100 mL). The organic layer was washed with aqueous sodium hydrogencarbonate (1 N, 25 mL). Drying over magnesium sulphate, concentration under reduced pressure and purification by silica gel chromatography (eluent: ethyl acetate/heptane, 3:7, v/v) provided 1.50 g (80%) of the title compound as a white foam. ESI-MS: 258.2 (M+H)+, 280.3 (M+Na)+, 202.2 (M+H—C4H8)+, 158.2 (M+H-Boc)+. Rf (silica gel; ethyl acetate/heptane, 1:4, v/v): 0.31.

1. extractionthe heterogeneous mixture was extracted with Et2O (2×100 mL)
2. washThe organic layer was washed with aqueous sodium hydrogencarbonate (1 N, 25 mL)
3. dry with materialDrying over magnesium sulphate, concentration under reduced pressure and purification by silica gel chromatography (eluent: ethyl acetate/heptane, 3:7, v/v)

ORD 기록

ord-5fb9763043eb42759d05bd7c51f3c67c

출처 데이터셋

uspto-grants-2005_06

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US06903107B1