Hydrochloric Acid → 7-Bromo-3,3-dimethyl-2,3-dihydro-benzofuran-5-carbaldehyde

HRID 460290Notes

Reaction equation

HRID 460290 reaction equation
[Al+3].[Cl-].[Cl-].[Cl-].[CH3:5][C:6]1([CH3:17])[C:10]2[CH:11]=[C:12]([CH:15]=[O:16])[CH:13]=[CH:14][C:9]=2[O:8][CH2:7]1.[Br:18]Br.Cl>ClCCl>[Br:18][C:14]1[C:9]2[O:8][CH2:7][C:6]([CH3:17])([CH3:5])[C:10]=2[CH:11]=[C:12]([CH:15]=[O:16])[CH:13]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 24408BromineHCID 6451240Aluminum(III) ChlorideHCID 205361803,3-Dimethyl-2,3-dihydrobenzofuran-5-carbaldehyde

Product 1

HCID 184454227-Bromo-3,3-dimethyl-2,3-dihydro-benzofuran-5-carbaldehydeYield 91.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a solution of AlCl3 (1.22 g, 9.18 mmol) in dry dichloromethane (15 mL) was added dropwise at room temperature 3,3-dimethyl-2,3-dihydro-benzofuran-5-carbaldehyde (647 mg, 3.67 mmol) in dichloromethane (15 mL) followed by bromine (0.23 mL, 4.41 mmol) and the reaction stirred for 3 hours. 1N HCl was added slowly and the layers separated. The aqueous layer was extracted twice with dichloromethane. The combined organic layers were washed successively with water and brine, dried over anhydrous magnesium sulfate, filtered and evaporated. The residue was chromatographed on silica gel (20% ethyl acetate in hexane) to give 856 mg of 7-bromo-3,3-dimethyl-2,3-dihydro-benzofuran-5-carbaldehyde (91%). 1H NMR (300 MHz; CDCl3): 1.40(s, 6H), 4.46 (s, 2H), 7.61 (s, 1H), 7.83 (s, 1H), 9.80 (s, 1H).

Workup

  1. customthe layers separated
  2. extractionThe aqueous layer was extracted twice with dichloromethane
  3. washThe combined organic layers were washed successively with water and brine
  4. dry with materialdried over anhydrous magnesium sulfate
  5. filtrationfiltered
  6. customevaporated
  7. customThe residue was chromatographed on silica gel (20% ethyl acetate in hexane)

Sources & evidence

ORD record
ord-ed79324e1e1940d88aefca98ea74b8f3
Source dataset
uspto-grants-2007_03
Patent number
US07196108B2

Reaction notes

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