Hydrochloric Acid → 3,4-Dibromo-2-furancarboxaldehyde

HRID 1735383Notes

Reaction equation

HRID 1735383 reaction equation
C([Li])(C)(C)C.[Br:6][C:7]1[C:11]([Br:12])=[CH:10][O:9][CH:8]=1.CN(N[CH:17]=[O:18])C.Cl>C1COCC1>[Br:12][C:11]1[C:7]([CH:17]=[O:18])=[CH:8][O:9][CH:10]=1.[Br:6][C:7]1[C:11]([Br:12])=[CH:10][O:9][C:8]=1[CH:17]=[O:18]

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 304376N',N'-DimethylformohydrazideHCID 6414823,4-DibromofuranHCID 178418306HCID 178418306, compound

Product 2

HCID 34659274-Bromofuran-3-carbaldehydeHCID 194371373,4-Dibromo-2-furancarboxaldehydeYield 69.1%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-70 °C

Procedure

t-Butyl lithium (1.7M in hexane) (29.23 ml, 49.7 mmol) was added dropwise to 3,4-dibromofuran (11.23 g, 49.7 mmol) in THF (120 ml) maintaining the temperature below -65° C. After 1 h at -70° C. dimethylaminoformamide (7.70 ml, 99.4 mmol) was added dropwise. After 2 h at -70° C. the solution was warmed to room temperature, acidified with 6N hydrochloric acid and the solution extracted with ethyl acetate. Drying (Na2SO4), evaporation to dryness under reduced pressure and purification by flash chromatography using hexane/dichloromethane (1:1) as eluent gave a mixture (3:1) of 3-bromofuran-4-carboxaldehyde and 3,4-dibromofuran-2-carboxaldehyde (4.36 g). This mixture (4.36 g) was treated with sodium borohydride (0.54 g, 14.25 mmol) in aqueous ethanol (4:1) (50ml) at 5° C. After 2 h at 5° C. the mixture was acidified with 6N hydrochloric acid and the solution extracted with ethyl acetate. Drying (Na2SO4), evaporation to dryness under reduced pressure and purification by flash chromatography using dichloromethane/hexane (4:1) as eluent gave the title compound (1.55 g, 18% ) as an amorphous yellow solid; δH (CDCl3) 1.74 (1H, br, s, OH), 4.54 (2H, s, CH2), 7.40-7.47 (2H, m, 2 and 5-H); δC (CDCl3) 55.4 (CH2), 100.7 (C-3), 125.4 (C-4), 141.1, 141.5; m/z 178 (M+, 97%), 176 (100%); (Found: M+, 175.9476. C5H5O2Br requires M, 175.9473).

Workup

  1. temperaturemaintaining the temperature below -65° C
  2. extractionthe solution extracted with ethyl acetate
  3. customDrying
  4. custom(Na2SO4), evaporation to dryness
  5. customunder reduced pressure and purification by flash chromatography

Sources & evidence

ORD record
ord-2d01ad3b587c496c88ce13c21b071553
Source dataset
uspto-grants-1996_07
Patent number
US05536745

Reaction notes

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