Monobenzone → Benzo(B)Thiophene

HRID 2396491Notes

Reaction equation

HRID 2396491 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 collidine under N2 was added 4-benzyloxyphenol (97.6 g, 0.488 mol) and cuprous oxide (23.3 g, 0.163 mol). The mixture was heated to reflux for 24 hours. Upon cooling, the reaction mixture was diluted with ethyl acetate (200 mL) and the crude mixture filtered through a pad of Celite® (Aldrich, Milwaukee, Wis.) to remove inorganic salts. The filtrate was washed with 1[hydrochloric acid (3×150 mL). The organic was 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 was 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)phenoxy]benzo-[b]thiophene as an off-white solid. mp 84°-86 ° C. 1H NMR (CDCl3) δ7.91-7.83 (m, 2H), 7.47-7.34 (m, 7H), 7.04 (q, JAB =9.0 Hz, 4H), 6.47 (s, 1H), 5.07 (s, 2H). Anal. Calcd. for C21H16O2S: C, 75.88; H, 4.85. Found: C, 75.75; H, 5.00.

Workup

  1. temperatureThe mixture was heated
  2. temperatureto reflux for 24 hours
  3. temperatureUpon cooling
  4. filtrationthe crude mixture filtered through a pad of Celite® (Aldrich, Milwaukee, Wis.)
  5. customto remove inorganic salts
  6. washThe filtrate was washed with 1[hydrochloric acid (3×150 mL)
  7. dry with materialThe organic was 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 was chromatographed (silicon dioxide, hexanes: ethyl acetate 85:15)

Sources & evidence

ORD record
ord-c6483b769d8c44589846684c163224df
Source dataset
uspto-grants-1996_02
Patent number
US05492922

Reaction notes

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