Potassium Carbonate → 6-fluoro-3-(5-methyl-1,2,4-oxadiazol-3-ylmethyl)-2(3H)-benzothiazolone

Beteiligte Stoffe

Reaktionsschritte

A mixture of 6-fluoro-2(3H)-benzothiazolone (8.45 g), acetonitrile (100 ml) and potassium carbonate (7.6 g) was prepared. To this mixture was added dropwise 3-chloromethyl-5-methyl-1,2,4-oxadiazole (7.3 g) at a temperature of 40° to 50° C. under stirring. The reaction mixture was heated under refluxing for 5 hours. The reaction mixture was then cooled and filtered. The filtrate was distilled under a reduced pressure, and the residue was admixed with ethyl acetate (200 ml) and water (100 ml). The resultant organic layer was separated and washed with a 5% aqueous potassium hydroxide solution, with water and then with a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate. The solvent was distilled off, and the residue was dissolved in a minimum amount of ethanol under heating. The solution thus formed was cooled to a temperature of 0° to 5° C. to precipitate a crystalline product, which was then separated by filtration, and dried, so that the aimed compound, i.e. 6-fluoro-3-(5-methyl-1,2,4-oxadiazol-3-ylmethyl)-2(3H)-benzothiazolone (12.1 g) was obtained. m.p. 142°-144° C.

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