Citric Acid → tert-Butyl cyclohexyl(3-hydroxypropyl)carbamate

Participants

Reaction Steps

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.

Provenance & Evidence