Phosphoric Acid → 7-Bromo-1-benzofuran

HRID 552072Notes

Reaction equation

HRID 552072 reaction equation
C(=O)([O-])[O-].[K+].[K+].[Br:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[OH:14].CO[CH:17](OC)[CH2:18]Br.O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O.P(=O)(O)(O)O>CN(C=O)C.ClC1C=CC=CC=1>[Br:7][C:8]1[C:9]2[O:14][CH:18]=[CH:17][C:10]=2[CH:11]=[CH:12][CH:13]=1

Participants

8

Reactant 5

HCID 1004Phosphoric AcidHCID 72442-BromophenolHCID 11430Potassium CarbonateHCID 14812Phosphorus oxide (P4O10)HCID 816722-Bromo-1,1-dimethoxyethane

Product 1

HCID 1136287-Bromo-1-benzofuranYield 47%

Reagents, catalysts & solvents 2

HCID 6228DimethylformamideSolventHCID 7964ChlorobenzeneSolvent

Conditions

Temperature
95 °C

Procedure

A suspension of potassium carbonate (50.0 g, 362 mmol) in 100 ml of DMF was added sequentially with 2-bromophenol (20.6 g, 120 mmol) and bromoacetaldehyde dimethyl acetal (20.2 g, 120 mmol) and stirred at 95° C. for 15 hours. The reaction solution was concentrated, liquid separation was carried out with ethyl acetate-water, the organic layer was sequentially washed with an aqueous solution of 1M-sodium hydroxide and saturated sodium chloride water, and dried with anhydrous magnesium sulfate. The residue obtained by concentration was dissolved in 200 ml of chlorobenzene, added at room temperature to a solution comprising diphosphorus pentoxide (8.07 g, 56.8 mmol) and 85% phosphoric acid (27 ml), which was stirred at 95° C. for 15 hours. After cooling to room temperature, the mixture was poured over ice water, stirred, and then extracted with dichloromethane. The organic layer was washed with saturated sodium chloride water and dried with anhydrous magnesium sulfate. The residue obtained by concentration was purified by silica gel chromatography (100% hexane) to obtain an oily product (10.4 g, 47%).

Workup

  1. concentrationThe reaction solution was concentrated
  2. customliquid separation
  3. washthe organic layer was sequentially washed with an aqueous solution of 1M-sodium hydroxide and saturated sodium chloride water
  4. dry with materialdried with anhydrous magnesium sulfate
  5. customThe residue obtained by concentration
  6. stirringwas stirred at 95° C. for 15 hours
  7. temperatureAfter cooling to room temperature
  8. stirringstirred
  9. extractionextracted with dichloromethane
  10. washThe organic layer was washed with saturated sodium chloride water
  11. dry with materialdried with anhydrous magnesium sulfate
  12. customThe residue obtained by concentration
  13. customwas purified by silica gel chromatography (100% hexane)

Sources & evidence

ORD record
ord-df8e1cd1c7a4439680a5d93d1d1d0f67
Source dataset
uspto-grants-2011_05
Patent number
US07951799B2

Reaction notes

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