Acetic Acid → 5-Chloro-2-(methylsulfonyl)benzo[d]thiazole
Reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[S:9][C:8](SC)=[N:7][C:6]=2[CH:12]=1.[Mn]([O-])(=O)(=O)=O.[K+].OO.[S:21]([O-:25])([O-])(=[O:23])=S.[Na+].[Na+].[C:28](O)(=O)C>>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[S:9][C:8]([S:21]([CH3:28])(=[O:25])=[O:23])=[N:7][C:6]=2[CH:12]=1Participants
Procedure
A mixture of 1.80 g (8.34 mmols) of 5-chloro-2-methylthiobenzothiazole, 1.80 g (11.39 mmols) of potassium permanganate and 45 ml of 50% aqueous acetic acid solution was stirred at room temperature for an hour. After the reaction, a 30.0 to 35.5% aqueous hydrogen peroxide solution was dropwise added to the mixture with stirring under ice cooling until to be colorless. An aqueous sodium thiosulfate was added to the mixture followed by extraction of the solution with chloroform. The chloroform layer was dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure to afford 2.05 g (yield: 100%) of 5-chloro-2-methanesulfonylbenzothiazole. A mixture of 1.64 g (6.62 mmols) of the above compound, 2.57 g (9.91 mmols) of Compound b obtained in Reference Example 2 and 40 ml of acetonitrile was heated under reflux for 20 hours. The mixture was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (eluent: chloroform/methanol =100/1).
Workup
- customAfter the reaction
- stirringwith stirring under ice cooling until
- extractionfollowed by extraction of the solution with chloroform
- dry with materialThe chloroform layer was dried over anhydrous sodium sulfate
- customthe solvent was evaporated under reduced pressure
Sources & evidence
- ORD record
- ord-e85f73c011aa41a6a1003f561526603f
- Source dataset
- uspto-grants-1991_10
- Patent number
- US05053408
Reaction notes
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