Benzenepropanoic acid → Benzo(b)thiophene-2-carboxylic acid
Reaction equation
[S:1](Cl)(Cl)=O.[C:5]([OH:15])(=[O:14])[CH2:6][CH2:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1.N1C=CC=CC=1>>[S:1]1[C:13]2[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=2[CH:7]=[C:6]1[C:5]([OH:15])=[O:14]Participants
Conditions
- Temperature
- 150 °C
Procedure
Thionyl chloride (5 eq.) was added dropwise to a round-bottom flask containing a mixture of hydrocinnamic acid (1 eq.) and pyridine (0.1 eq.) heated to 150° C. TLC after 3 h showed complete consumption of starting material. The reaction mixture was cooled to it and water (10 vol), 35% HCl (1 vol.), and THF (15 vol) were added and the mixture heated at 60° C. for 30 minutes. After 30 minutes, the THF was removed in vacuo and the obtained precipitate was filtered, dissolved in a 3:1 water:ethanol mixture (20 vol) and heated at 90° C. for 1 hr. After 1 h, the solution was cooled to it and allowed to stir overnight. The separated solid was filtered and recrystallized from toluene to get the corresponding benzothiophene-2-carboxylic acid. The results for various substituted chlorobenzothiophene carboxylic acids are given in Table 1.
Workup
- additioncontaining
- customconsumption of starting material
- temperatureThe reaction mixture was cooled to it and water (10 vol), 35% HCl (1 vol.), and THF (15 vol)
- additionwere added
- temperaturethe mixture heated at 60° C. for 30 minutes
- waitAfter 30 minutes
- customthe THF was removed in vacuo
- filtrationthe obtained precipitate was filtered
- dissolutiondissolved in a 3:1 water
- temperatureethanol mixture (20 vol) and heated at 90° C. for 1 hr
- waitAfter 1 h
- temperaturethe solution was cooled to it
- filtrationThe separated solid was filtered
- customrecrystallized from toluene
Sources & evidence
- ORD record
- ord-e2a409715c7549b2a9b85e698c0e63e4
- Source dataset
- uspto-grants-2016_05
- Patent number
- US09334256B2
Reaction notes
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