Citric Acid → tert-Butyl cyclohexyl(3-hydroxypropyl)carbamate
Reaction equation
[C:1]([O:5][C:6]([N:8]([CH:16]1[CH2:21][CH2:20][CH2:19][CH2:18][CH2:17]1)[CH2:9][CH2:10][C:11](OCC)=[O:12])=[O:7])([CH3:4])([CH3:3])[CH3:2].[H-].[Al+3].[Li+].[H-].[H-].[H-].C(OCC)(=O)C.C(O)(=O)CC(CC(O)=O)(C(O)=O)O>O1CCCC1>[C:1]([O:5][C:6]([N:8]([CH:16]1[CH2:17][CH2:18][CH2:19][CH2:20][CH2:21]1)[CH2:9][CH2:10][CH2:11][OH:12])=[O:7])([CH3:4])([CH3:2])[CH3:3]Participants
Procedure
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.
Workup
- extractionthe heterogeneous mixture was extracted with Et2O (2×100 mL)
- washThe organic layer was washed with aqueous sodium hydrogencarbonate (1 N, 25 mL)
- dry with materialDrying over magnesium sulphate, concentration under reduced pressure and purification by silica gel chromatography (eluent: ethyl acetate/heptane, 3:7, v/v)
Sources & evidence
- ORD record
- ord-5fb9763043eb42759d05bd7c51f3c67c
- Source dataset
- uspto-grants-2005_06
- Patent number
- US06903107B1
Reaction notes
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