Citric Acid → [(3R)-3-Hydroxybutyl]oxy-acetic acid tert.-butyl ester

HRID 1926891Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1926891
[CH2:1]([OH:6])[CH2:2][C@H:3]([OH:5])[CH3:4].Br[CH2:8][C:9]([O:11][C:12]([CH3:15])([CH3:14])[CH3:13])=[O:10].C(O)(=O)CC(CC(O)=O)(C(O)=O)O.C(OC(=O)C)(C)(C)C>C1COCC1.C(OCC)(=O)C.O>[C:12]([O:11][C:9](=[O:10])[CH2:8][O:6][CH2:1][CH2:2][C@H:3]([OH:5])[CH3:4])([CH3:15])([CH3:14])[CH3:13]

Komponenten

8

Edukt 4

HCID 311Citric AcidHCID 10908tert-Butyl acetateHCID 79177tert-Butyl bromoacetateHCID 637497(-)-1,3-Butanediol

Produkt 1

HCID 58016861[(3R)-3-Hydroxybutyl]oxy-acetic acid tert.-butyl ester

Reagenzien, Katalysatoren, Lösungsmittel 3

HCID 962WaterLösungsmittelHCID 8028TetrahydrofuranLösungsmittel2×HCID 8857Ethyl AcetateLösungsmittel

Reaktionsbedingungen

Temperatur
0 °C

Versuchsvorschrift

Put 1.0 g (11.1 mmol) (3R)-butane-1,3-diol in 20 ml THF at 0° C. Add dropwise 5.55 ml (11.1 mmol) of a 2 M solution of the phosphazene base P2-tert.-butyl in THF and stir for 30 min at 0° C. Then add 2.27 g (11.65 mmol) tert.-butyl bromoacetate. Stir for 30 min at 0° C., then leave to return to RT and stir for a further 1 h. Then dilute with ethyl acetate, add water and acidify with 10% citric acid solution. Extract once more with ethyl acetate, combine the organic phases, wash once with satd. sodium chloride solution, dry over magnesium sulphate and concentrate by evaporation. Purify by chromatography on silica gel (solvent: cyclohexane/ethyl acetate 8:2). 730 mg (32.2% of theor.) of the target compound is obtained, which according to 1H-NMR (doublet at 1.18 ppm) contains approx. 10% of the regioisomer [(1R)-3-hydroxy-1-methylpropyl]oxy}acetic acid tert.-butyl ester.

Aufarbeitung

  1. customat 0° C
  2. stirringStir for 30 min at 0° C.
  3. customleave
  4. customto return to RT
  5. stirringstir for a further 1 h
  6. extractionExtract once more with ethyl acetate
  7. washwash once with satd
  8. dry with materialsodium chloride solution, dry over magnesium sulphate
  9. concentrationconcentrate by evaporation
  10. customPurify by chromatography on silica gel (solvent: cyclohexane/ethyl acetate 8:2)
  11. custom730 mg (32.2% of theor.) of the target compound is obtained

Quellen und Nachweise

ORD-Eintrag
ord-75034a699d9a42ef87525d9175403313
Quelldatensatz
uspto-grants-2012_05
Patentnummer
US08183246B2

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