Potassium Hydroxide → 4-Chlorobenzo(b)thiophene-2-carboxylic Acid

HRID 1500538Notes

Reaction equation

HRID 1500538 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4](Cl)[C:3]=1[CH:9]=[C:10]([SH:14])[C:11]([OH:13])=[O:12].[OH-].[K+]>O>[C:11]([C:10]1[S:14][C:4]2[CH:5]=[CH:6][CH:7]=[C:2]([Cl:1])[C:3]=2[CH:9]=1)([OH:13])=[O:12]

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 867250762,6-Dichlorophenyl-2-mercapto-2-propenoic acid

Product 1

HCID 38545164-Chlorobenzo(b)thiophene-2-carboxylic Acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A suspension of (Z)-3-(2,6-dichlorophenyl-2-mercapto-2-propenoic acid (72.4 g) and water (362 ml) was stirred at room temperature. Further, potassium hydroxide (40.8 g) was added, and the mixture was heated under reflux for 4 hours. After the mixture was allowed to cool, the mixture was stirred for 1 hour while cooling with ice. The precipitated crystals ((Z)-3-(2,6-dichlorophenyl-2-mercapto-2-propenoic acid potassium salt) were collected by filtration and washed with cold water. After the crystals were suspended in water, 35% concentrated hydrochloric acid (32 ml) was added (pH=1), and the mixture was stirred at room temperature for 1 hour. The precipitated crystals were collected by filtration and dried to obtain 2-carboxy-4-chlorobenzo[b]thiophene.

Workup

  1. temperaturethe mixture was heated
  2. temperatureunder reflux for 4 hours
  3. temperatureto cool
  4. stirringthe mixture was stirred for 1 hour
  5. temperaturewhile cooling with ice
  6. filtrationThe precipitated crystals ((Z)-3-(2,6-dichlorophenyl-2-mercapto-2-propenoic acid potassium salt) were collected by filtration
  7. washwashed with cold water
  8. addition35% concentrated hydrochloric acid (32 ml) was added (pH=1)
  9. stirringthe mixture was stirred at room temperature for 1 hour
  10. filtrationThe precipitated crystals were collected by filtration
  11. customdried

Sources & evidence

ORD record
ord-864ea2c4cc714ea1b4de61211dc8dcf6
Source dataset
uspto-grants-2015_12
Patent number
US09206169B2

Reaction notes

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