Reaction #1088

Reaction equation

3-bromo-benzo[b]thiophene

4-benzyloxyphenol

→

benzo[b]thiophene

Yield 28.0%

Solvents

collidine

ethyl acetate

Conditions

Workup

1. 1
   TemperatureThe mixture was heated
2. 2
   Temperatureto reflux for 24 hours
3. 3
   TemperatureUpon cooling
4. 4
   Filtrationthe crude mixture filtered through a pad of Celite® (Aldrich, Milwaukee, Wis.)
5. 5
   Otherto remove inorganic salts
6. 6
   WashThe filtrate was washed with 1N hydrochloric acid (3×150 mL)
7. 7
   DryingThe organic was dried (sodium sulfate)
8. 8
   Concentrationconcentrated in vacuo to a liquid
9. 9
   OtherThianaphthene was removed by distillation (10 mm Hg, 115°-120° C.)
10. 10
    OtherThe remainder of the material was chromatographed (silicon dioxide, hexanes: ethyl acetate 85:15)

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 1N 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) d 7.91-7.83 (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.

Source