Trifluoroacetic acid → 5-Chloro-2-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)benzo-thiophene
Reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[S:9][C:8]([C:10]3(O)[CH2:15][CH2:14][N:13]([CH3:16])[CH2:12][CH2:11]3)=[CH:7][C:6]=2[CH:18]=1.FC(F)(F)C(O)=O>>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[S:9][C:8]([C:10]3[CH2:15][CH2:14][N:13]([CH3:16])[CH2:12][CH:11]=3)=[CH:7][C:6]=2[CH:18]=1Participants
Procedure
To 0.30 gm (1.06 mMol) 5-chloro-2-(1-methyl-4-hydroxy-1,2,3,6-tetrahydropyridin-4-yl)benzothiophene were added 4.0 mL trifluoroacetic acid. The reaction mixture was stirred for two hours at room temperature. The volatiles were removed under reduced pressure and the residue partitioned between aqueous sodium bicarbonate and dichloromethane. The phases were separated and the organic phase dried over sodium sulfate and then concentrated under reduced pressure. The residue was subjected to flash chromatography, eluting with chloroform containing 5% methanol. Fractions shown to contain product were combined and concentrated under reduced pressure to give 0.336 gm of 5-chloro-2-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)benzo-thiophene as an orange powder. A portion of this material was dissolved in ethyl acetate and treated with 1.0 equivalents of oxalic acid. The solution was concentrated under reduced pressure to give the title compound as a rust solid.
Workup
- customThe volatiles were removed under reduced pressure
- customthe residue partitioned between aqueous sodium bicarbonate and dichloromethane
- customThe phases were separated
- dry with materialthe organic phase dried over sodium sulfate
- concentrationconcentrated under reduced pressure
- washeluting with chloroform containing 5% methanol
- concentrationconcentrated under reduced pressure
Sources & evidence
- ORD record
- ord-12ffa0c3563a4c85b1706ea644c4e5a5
- Source dataset
- uspto-grants-1998_12
- Patent number
- US05846982
Reaction notes
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