1,2-Dibromoethane → 2,3-dihydro-1,4-benzodioxin-5-ylmethanol

HRID 557204Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 557204
[OH:1][C:2]1[C:9]([OH:10])=[CH:8][CH:7]=[CH:6][C:3]=1[CH:4]=[O:5].Br[CH2:12][CH2:13]Br.C(=O)([O-])[O-].[Cs+].[Cs+].[BH4-].[Na+]>CN(C)C=O.C(O)C>[O:10]1[C:9]2[CH:8]=[CH:7][CH:6]=[C:3]([CH2:4][OH:5])[C:2]=2[O:1][CH2:13][CH2:12]1

Komponenten

7

Edukt 4

HCID 78391,2-DibromoethaneHCID 10796Cesium carbonateHCID 905792,3-DihydroxybenzaldehydeHCID 4311764Sodium borohydride

Produkt 1

HCID 27761822,3-dihydro-1,4-benzodioxin-5-ylmethanolAusbeute 27 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 702EthanolLösungsmittelHCID 6228DimethylformamideLösungsmittel

Reaktionsbedingungen

Temperatur
20 °C

Versuchsvorschrift

Dissolve 2,3-dihydroxybenzaldehyde (25 g, 181 mmol) and 1,2-dibromoethane (34 g, 181 mmol) in N,N-dimethylformamide (500 mL). Add cesium carbonate (118 g, 362 mmol), stir and reflux under nitrogen for 2 hours. Cool the reaction to 20° C., dilute with absolute ethanol (250 mL) and add sodium borohydride (6.8 g, 181 mmol). Stir at 20° C. for 1 hour and concentrate under high vacuum to remove the ethanol and dimethylformamide. Dilute the residue with diethyl ether and wash with distilled water, 0.25 molar aqueous sodium hydroxide, and aqueous saturated sodium chloride. Dry the organic phase over anhydrous magnesium sulfate, filter and concentrate under reduced pressure. Chromatograph on flash silica using a gradient from 75% hexane, 25% ethyl acetate to 25% hexane, 75% ethyl acetate to obtain 8.1 g (27%) of the desired compound as a white solid.

Aufarbeitung

  1. temperaturereflux under nitrogen for 2 hours
  2. temperatureCool
  3. customthe reaction to 20° C.
  4. concentrationconcentrate under high vacuum
  5. customto remove the ethanol and dimethylformamide
  6. additionDilute the residue with diethyl ether
  7. washwash with distilled water, 0.25 molar aqueous sodium hydroxide, and aqueous saturated sodium chloride
  8. dry with materialDry the organic phase over anhydrous magnesium sulfate
  9. filtrationfilter
  10. concentrationconcentrate under reduced pressure

Quellen und Nachweise

ORD-Eintrag
ord-cd67db792ba44d51abead1f9f9774e67
Quelldatensatz
uspto-grants-2011_11
Patentnummer
US08058425B2

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