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

HRID 557204Notes

Reaction equation

HRID 557204 reaction equation
[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

Participants

7

Reactant 4

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

Product 1

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

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 6228DimethylformamideSolvent

Conditions

Temperature
20 °C

Procedure

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.

Workup

  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

Sources & evidence

ORD record
ord-cd67db792ba44d51abead1f9f9774e67
Source dataset
uspto-grants-2011_11
Patent number
US08058425B2

Reaction notes

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