Sodium borohydride → 6-Methoxy-1-benzothiophene

HRID 2267461Notes

Reaction equation

HRID 2267461 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]2[C:10](=O)[CH2:9][S:8][C:7]=2[CH:12]=1.[BH4-].[Na+]>CO.[OH-].[Na+]>[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]2[CH:10]=[CH:9][S:8][C:7]=2[CH:12]=1

Participants

5

Reactant 2

HCID 4311764Sodium borohydrideHCID 121016256-Methoxybenzo[B]thiophen-3(2H)-one

Product 1

HCID 136342376-Methoxy-1-benzothiopheneYield 66.1%

Reagents, catalysts & solvents 2

HCID 887MethanolSolvent2×HCID 14798Sodium HydroxideSolvent2×

Procedure

6-Methoxybenzo[b]thiophen-3(2H)-one (1.4 g, 7.76 mmol) was dissolved in a mixture of methanol (18 mL) and 2.5 M sodium hydroxide (3 mL). The mixture was treated with sodium borohydride (0.589 g, 15 mmol) in 10 mL of methanol and 3 mL of 2.5 M sodium hydroxide. The reflux was heated to reflux for 1 h and then at 60° C. overnight. The reaction was cooled down to room temperature and the methanol removed in vacuo. The remaining aqueous layer was acidified to pH 4 with 1 N hydrochloric acid. The aqueous layer was extracted with ethyl acetate and washed with 1 N HCl. The organic layer was further washed with water, saturated sodium bicarbonate, water and brine. The organic layer was dried with sodium sulfate, concentrated and purified by flash chromatography using a gradient of 20 to 50% ethyl acetate in hexanes to afford a clear oil (0.843 g).

Workup

  1. temperatureThe reflux was heated
  2. temperatureto reflux for 1 h
  3. customat 60° C.
  4. customovernight
  5. customthe methanol removed in vacuo
  6. extractionThe aqueous layer was extracted with ethyl acetate
  7. washwashed with 1 N HCl
  8. washThe organic layer was further washed with water, saturated sodium bicarbonate, water and brine
  9. dry with materialThe organic layer was dried with sodium sulfate
  10. concentrationconcentrated
  11. custompurified by flash chromatography

Sources & evidence

ORD record
ord-83f1c0e68ae24839903fccd988ad638b
Source dataset
uspto-grants-2010_12
Patent number
US07858785B2

Reaction notes

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