Sulfuric Acid → 3-Methylbenzothiophene-2-sulfonic acid

HRID 589665Notes

Reaction equation

HRID 589665 reaction equation
[CH3:1][C:2]1[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[S:4][CH:3]=1.CC(OC(C)=O)=O.[OH:18][S:19](O)(=[O:21])=[O:20]>CCOC(C)=O>[CH3:1][C:2]1[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[S:4][C:3]=1[S:19]([OH:21])(=[O:20])=[O:18]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 7918Acetic AnhydrideHCID 738173-Methylbenzo[b]thiophene

Product 1

HCID 866891873-Methylbenzothiophene-2-sulfonic acidYield 14%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent2×

Procedure

A solution of 3-methyl-benzothiophene (900 mg, 6.1 mmol), Ac2O (1.75 mL, 18.5 mmol) and conc. H2SO4 (350 μL, 6.2 mmol) in EtOAc (5 mL) was stirred at room temperature for 3 h. The reaction mixture was diluted with EtOAc. The organic phase was washed with water and brine and then dried. Upon evaporation of some of the solvent the product precipitated. Et2O was added, and the precipitate was collected giving 193 mg of 3-methylbenzothiophene-2-sulfonic acid (14%). 1H NMR (400 MHz, DMSO-d6) δ ppm 2.48 (s, 3 H) 7.33-7.41 (m, 2 H) 7.69-7.75 (m, 1 H) 7.83-7.88 (m, 1 H).

Workup

  1. washThe organic phase was washed with water and brine
  2. customdried
  3. customUpon evaporation of some of the solvent the product
  4. customprecipitated
  5. additionEt2O was added
  6. customthe precipitate was collected

Sources & evidence

ORD record
ord-d3d28db330034b46a31d125319666be0
Source dataset
uspto-grants-2016_01
Patent number
US09233946B2

Reaction notes

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