(S)-Tert-butyl 2,2-dimethyl-4-(2-oxoethyl)oxazolidine-3-carboxylate → 2,2-Dimethyloxazolidine-3-carboxylic acid tert-butyl ester

HRID 1807921Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1807921
[C:1]([O:5][C:6]([N:8]1[C@@H:12](CC=O)[CH2:11][O:10][C:9]1([CH3:17])[CH3:16])=[O:7])([CH3:4])([CH3:3])[CH3:2].C[Mg]Br>C(OCC)C>[C:1]([O:5][C:6]([N:8]1[CH2:12][CH2:11][O:10][C:9]1([CH3:17])[CH3:16])=[O:7])([CH3:4])([CH3:2])[CH3:3]

Komponenten

4

Edukt 2

HCID 10586317(S)-Tert-butyl 2,2-dimethyl-4-(2-oxoethyl)oxazolidine-3-carboxylateHCID 178418573HCID 178418573, Verbindung

Produkt 1

HCID 545314052,2-Dimethyloxazolidine-3-carboxylic acid tert-butyl esterAusbeute 59,3 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 3283Diethyl EtherLösungsmittel2×

Versuchsvorschrift

To a stirred solution of (S)-2,2-dimethyl-4-(2-oxo-ethyl)-oxazolidine-3-carboxylic acid tert-butyl ester (12.0 g; CAS 147959-19-1) in dry diethyl ether (200 ml) under an argon atmosphere at room temperature was added dropwise a solution of methylmagnesium bromide in diethyl ether (49.3 ml, 3 M solution) and stirring continued overnight. The reaction mixture was then quenched by careful addition of water and extracted twice with ethyl acetate. The combined organic phases were dried over sodium sulphate, filtered and concentrated in vacuo. The reside was purified by column chromatography (SiO2; gradient: heptane/EtOAc 100:0→50:50) to give (S)-4-(R)-2-hydroxy-propyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester (5.89 g) from fractions eluting first and (S)-4-(S)-2-hydroxy-propyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester (4.07 g) from fractions eluting later, both compounds as light yellow oils. (S)-4-(R)-2-hydroxy-propyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester: 1H NMR δ (CDCl3, 300 MHz): 4.60 (1H, br. D, J=3.3 Hz), 4.23 (1H, m), 4.00 (1H, dd, J=8.7 & 5.4 Hz), 3.71 (1H, m), 3.65 (1H, d, J=8.7 Hz), 1.76 (1H, td, J=11.4 & 2.1 Hz), 1.61-1.46 (16H, m), 1.20 (3H, d, J=6.3 Hz). (S)-4-(S)-2-hydroxy-propyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester: 1H NMR δ (CDCl3, 300 MHz): 4.13 (1H, m), 3.98 (1H, m), 3.85-3.60 (2H, m), 2.50 (1H, br. s), 1.80 (1H, m), 1.60-1.49 (16H, m), 1.22 (3H, d, J=6.3 Hz).

Aufarbeitung

  1. customThe reaction mixture was then quenched by careful addition of water
  2. extractionextracted twice with ethyl acetate
  3. dry with materialThe combined organic phases were dried over sodium sulphate
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo
  6. customThe reside was purified by column chromatography (SiO2; gradient: heptane/EtOAc 100:0→50:50)

Quellen und Nachweise

ORD-Eintrag
ord-76d2c490273c4b71a8ebf03981f8a706
Quelldatensatz
uspto-grants-2013_01
Patentnummer
US08357712B2

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