Monobenzone → Benzo(B)Thiophene

HRID 1602922Notes

Reaction equation

HRID 1602922 reaction equation
Br[C:2]1[C:3]2[CH:10]=[CH:9][CH:8]=[CH:7][C:4]=2[S:5][CH:6]=1.C(OC1C=CC(O)=CC=1)C1C=CC=CC=1>N1C(C)=CC(C)=CC=1C.C(OCC)(=O)C>[S:5]1[CH:6]=[CH:2][C:3]2[CH:10]=[CH:9][CH:8]=[CH:7][C:4]1=2

Participants

5

Reactant 2

HCID 7638MonobenzoneHCID 123250Benzo(b)thiophene, 3-bromo-

Product 1

HCID 7221Benzo(B)ThiopheneYield 28%

Reagents, catalysts & solvents 2

HCID 79532,4,6-TrimethylpyridineSolventHCID 8857Ethyl AcetateSolvent

Procedure

To a solution of 3-bromo-benzo[b]thiophene (69.62 g, 0.325 mol) in 55 mL of anhydrous 2,4,6-collidine under N2 is added 4-benzyloxyphenol (97.6 g, 0.488 mol) and cuprous oxide (23.3 g, 0.163 mol). The mixture is heated to reflux for 24 hours. Upon cooling, the reaction mixture is diluted with ethyl acetate (200 mL) and the crude mixture is filtered through a pad of Celite® (Aldrich, Milwaukee, Wis.) to remove inorganic salts. The filtrate is washed with 1N hydrochloric acid (3×150 mL). The organic is dried (sodium sulfate) and concentrated in vacuo to a liquid. Thianaphthene was removed by distillation (10 mm Hg, 115-120° C.). The remainder of the material is chromatographed (silicon dioxide, hexanes: ethyl acetate 85:15) to provide 12.2 g of benzo[b]thiophene and 12.95 g (35% based on recovered starting material) of 3-(4-benzyloxy)phenoxybenzo[b]thiophene as an off-white solid.

Workup

  1. temperatureThe mixture is heated
  2. temperatureto reflux for 24 hours
  3. temperatureUpon cooling
  4. filtrationthe crude mixture is filtered through a pad of Celite® (Aldrich, Milwaukee, Wis.)
  5. customto remove inorganic salts
  6. washThe filtrate is washed with 1N hydrochloric acid (3×150 mL)
  7. dry with materialThe organic is dried (sodium sulfate)
  8. concentrationconcentrated in vacuo to a liquid
  9. customThianaphthene was removed by distillation (10 mm Hg, 115-120° C.)
  10. customThe remainder of the material is chromatographed (silicon dioxide, hexanes: ethyl acetate 85:15)

Sources & evidence

ORD record
ord-79baf52d5b2745ae8b0cbb8c0b578446
Source dataset
uspto-grants-1999_11
Patent number
US05985897

Reaction notes

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