Boc-L-dopa tetrabutylammonium salt → (2r)-2-Acetyloxypropyl (2s)-3-(3,4-dihydroxyphenyl)-2-[(tert-butoxy)carbonylamino]propanoate
Reaction equation
C([N+](C[CH2:15][CH2:16][CH3:17])(CCCC)CCCC)CCC.[C:18]([NH:25][C@@H:26]([CH2:30][C:31]1[CH:38]=[C:36]([OH:37])[C:34]([OH:35])=[CH:33][CH:32]=1)[C:27]([OH:29])=[O:28])([O:20][C:21]([CH3:24])([CH3:23])[CH3:22])=[O:19]>CC(N(C)C)=O.C(OC)(C)(C)C>[OH:37][C:36]1[CH:38]=[C:31]([CH2:30][C@H:26]([NH:25][C:18]([O:20][C:21]([CH3:23])([CH3:24])[CH3:22])=[O:19])[C:27]([O:29][CH2:17][C@H:16]([O:29][C:27](=[O:28])[CH3:26])[CH3:15])=[O:28])[CH:32]=[CH:33][C:34]=1[OH:35]Participants
4
Procedure
A solution of Boc-L-Dopa tetrabutyl ammonium salt (5.6 g, 104.0 mmol) and crude (1R)-2-bromomethylethyl acetate (46) (2.6 g, 11.6 mmol) in 50-mL dimethylacetamide was stirred overnight at 65° C. The reaction mixture was diluted with methyl tert-butyl ether (500 mL), washed with saturated aqueous NaHCO3 (3×250 mL), brined, dried over Na2SO4, and concentrated to an oil. Chromatography eluting with EtOAc/hexane (2:3) gave 1.5 g (36.7% yield) of the title compound (47). 1H NMR (400 MHz, CDCl3): δ 1.23 (d, J=6.8 Hz, 3H), 1.43 (s, 9H), 2.10 (s, 3H), 2.98 (m, 2H), 4.02 (dd, J=7.2, 6.8 Hz, 1H), 4.30 (dd, J=6.8, 2.8 Hz, 1H), 4.54 (m, 1H), 4.97 (d, 1H, NH), 5.10 (m, 1H). MS (ESI) m/z 398.1 (M+H)+ and 396.1 (M−H)−.
Workup
- washwashed with saturated aqueous NaHCO3 (3×250 mL)
- dry with materialdried over Na2SO4
- concentrationconcentrated to an oil
- washChromatography eluting with EtOAc/hexane (2:3)
Sources & evidence
- ORD record
- ord-3306f57774f840269a45981ed71e0d5c
- Source dataset
- uspto-grants-2010_11
- Patent number
- US07829592B2
Reaction notes
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