Sulfuric Acid → 2-(1-Benzothiophen-5-yl)ethan-1-ol

HRID 2390971Notes

Reaction equation

HRID 2390971 reaction equation
[BH4-].[Na+].[S:3]1[C:7]2[CH:8]=[CH:9][C:10]([CH2:12][C:13](O)=[O:14])=[CH:11][C:6]=2[CH:5]=[CH:4]1.S(=O)(=O)(O)O>O1CCCC1>[S:3]1[C:7]2[CH:8]=[CH:9][C:10]([CH2:12][CH2:13][OH:14])=[CH:11][C:6]=2[CH:5]=[CH:4]1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 4311764Sodium borohydrideHCID 11469582Benzo[b]thiophene-5-acetic acid

Product 1

HCID 119833712-(1-Benzothiophen-5-yl)ethan-1-olYield 89%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
66 °C

Procedure

To 40 mL of tetrahydrofuran was suspended 4.72 g of sodium borohydride, to this solution were dropwise added tetrahydrofuran (60 mL) solution of 20 g of (1-benzothiophen-5-yl)acetic acid, and 6.12 g of sulfuric acid. The solution was heated to 66° C., followed by distilling off about 40 mL of the solvent under normal pressure, which was then stirred at same temperature for 1 hour. After cooling, to this reaction mixture was dropwise added 10 mL of acetone, which was then stirred for 30 minutes. Thereto were added 90 mL of water and 80 mL of toluene. The organic layer was separated, to which was added 60 mL of water, and the pH was adjusted to 13.6 with 5 mL of 5 mol/L sodium hydroxide aqueous solution. The organic layer was separated, washed with water, followed by distilling off the solvent, and thereto were added cyclohexane and toluene. The precipitate was collected by filtration to provide 16.5 g of 2-(1-benzothiophen-5-yl)ethanol as white solid form.

Workup

  1. distillationby distilling off about 40 mL of the solvent under normal pressure, which
  2. temperatureAfter cooling, to this reaction mixture
  3. stirringwas then stirred for 30 minutes
  4. additionThereto were added 90 mL of water and 80 mL of toluene
  5. customThe organic layer was separated, to which
  6. additionwas added 60 mL of water
  7. customThe organic layer was separated
  8. washwashed with water
  9. distillationby distilling off the solvent
  10. additionwere added cyclohexane and toluene
  11. filtrationThe precipitate was collected by filtration

Sources & evidence

ORD record
ord-54cd4716e062414f8768619f7a30ba96
Source dataset
uspto-grants-2012_09
Patent number
US08273902B2

Reaction notes

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