1,2-Dibromoethane → Methyl 2,3-dihydro-1,4-benzodioxine-6-carboxylate

HRID 1908956Notes

Reaction equation

HRID 1908956 reaction equation
[CH3:1][O:2][C:3](=[O:12])[C:4]1[CH:9]=[CH:8][C:7]([OH:10])=[C:6]([OH:11])[CH:5]=1.Br[CH2:14][CH2:15]Br.[OH-].[K+]>CO>[O:10]1[CH2:15][CH2:14][O:11][C:6]2[CH:5]=[C:4]([C:3]([O:2][CH3:1])=[O:12])[CH:9]=[CH:8][C:7]1=2

Participants

5

Reactant 3

HCID 78391,2-DibromoethaneHCID 14797Potassium HydroxideHCID 287064Methyl 3,4-Dihydroxybenzoate

Product 1

HCID 3802178Methyl 2,3-dihydro-1,4-benzodioxine-6-carboxylateYield 13%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A mixture of 3,4-dihydroxybenzoic acid methyl ester (5.2 g, 31 mmol), 1,2-dibromoethane (2.9 mL, 34 mmol), and pulverized KOH (3.8 g, 68 mmol) in MeOH was heated at reflux for 30 hrs. After removal of the solvent under reduced pressure, the residue was partitioned between ethyl acetate and water. The ethyl acetate layer was washed with water, dried over MgSO4, concentrated in vacuo and purified by purified by column chromatography on silica gel eluting with 40% ethyl acetate in hexane to yield methyl 2,3-dihydrobenzo[b][1,4]dioxine-6-carboxylate (780 mg, 13%) along with the unreacted starting material (2.6 g). 1H NMR (DMSO-d6, 600 MHz) δ 7.45 (d, 1H, J=8.4 Hz), 7.39 (s, 1H), 6.96 (d, 1H, J=8.4 Hz), 4.33-4.28 (m, 4H), 3.80 (s, 3H); MS (ES+) m/z 195.1 (M+H)+

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 30 hrs
  3. customAfter removal of the solvent under reduced pressure
  4. customthe residue was partitioned between ethyl acetate and water
  5. washThe ethyl acetate layer was washed with water
  6. dry with materialdried over MgSO4
  7. concentrationconcentrated in vacuo
  8. custompurified
  9. customby purified by column chromatography on silica gel eluting with 40% ethyl acetate in hexane

Sources & evidence

ORD record
ord-4ca7b3ebe82d49eaac834f05f8b5f7db
Source dataset
uspto-grants-2013_12
Patent number
US08598342B2

Reaction notes

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