Iodine → 6-Hydroxy-5-methoxybenzo[b]thiophene-2-carboxylic acid

HRID 2232366Notes

Reaction equation

HRID 2232366 reaction equation
II.[OH:3][C:4]1[CH:9]=[CH:8][C:7]([CH:10]=[C:11]([SH:15])[C:12]([OH:14])=[O:13])=[CH:6][C:5]=1[O:16][CH3:17].S(=O)(O)[O-].[Na+]>C(O)C>[OH:3][C:4]1[C:5]([O:16][CH3:17])=[CH:6][C:7]2[CH:10]=[C:11]([C:12]([OH:14])=[O:13])[S:15][C:8]=2[CH:9]=1

Participants

5

Reactant 3

HCID 807IodineHCID 27478852-Propenoic acid, 3-(4-hydroxy-3-methoxyphenyl)-2-mercapto-HCID 23665763Sodium Bisulfite

Product 1

HCID 212834786-Hydroxy-5-methoxybenzo[b]thiophene-2-carboxylic acid

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Iodine (90 g) was added to a stirred mixture of the product from Step B (73 g) and 90% ethanol (2000 mL). The resultant dark mixture was heated at reflux for 24 hours. Saturated sodium bisulfite solution (20 mL) was added to the cooled reaction mixture and the ethanol was removed in vacuo. The aqueous residue was diluted to 1500 ml with water and extracted with ethyl acetate (4×400 mL). The combined extracts were evaporated in vacuo and the residue was heated on the steam bath with 1N sodium hydroxide solution (1500 mL) for 3 hours. The solution was treated with charcoal, filtered, diluted to 2500 mL with water and acidified with concentrated hydrochloric acid. The precipitated solid was collected, washed with water and dried; yield 36.8 g.

Workup

  1. temperatureThe resultant dark mixture was heated
  2. temperatureat reflux for 24 hours
  3. customthe ethanol was removed in vacuo
  4. additionThe aqueous residue was diluted to 1500 ml with water
  5. extractionextracted with ethyl acetate (4×400 mL)
  6. customThe combined extracts were evaporated in vacuo
  7. temperaturethe residue was heated on the steam bath with 1N sodium hydroxide solution (1500 mL) for 3 hours
  8. additionThe solution was treated with charcoal
  9. filtrationfiltered
  10. additiondiluted to 2500 mL with water
  11. customThe precipitated solid was collected
  12. washwashed with water
  13. customdried

Sources & evidence

ORD record
ord-25559342262a444b90f5bf617a2ec2c0
Source dataset
uspto-grants-1988_11
Patent number
US04788192

Reaction notes

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