反应详情

8.5 g (0.061 mole) of 3,5-dimethylthiophenol, 6.2 g (0.061 mole) of triethylamine and 14.3 g (0.061 mole) of 2 -bromo-5-trifluoromethyl-1,3,4-thiadiazole in 150 mole of tetrahydrofuran were stirred for 30 minutes under reflux. The salt (by-product) which had precipitated was filtered off and washed thoroughly with tetrahydrofuran. After distilling off the solvent in vacuo, a colorless oil passed over on distillation. 16.8 g (95% of theory) of 2-(3',5'-dimethylphenylthio)-5-trifluoromethyl-1,3,4-thiadiazole of boiling point 107°-108° C/10.2 mm Hg were obtained. 22.8 g (0.201 mole) of hydrogen peroxide (30% strength) in 100 ml of glacial acetic acid were added thereto and the reaction mixture was stirred for 15 hours at 60° C, and poured onto ice water. The precipitate was filtered off and recrystallized from ethanol. 12.7 g (54% of theory) of 2-(3',5'-dimethylphenylsulfonyl)-5-trifluoromethyl-1,3,4-thiadiazole of melting point 110° C were obtained.

1. temperatureunder reflux
2. customThe salt (by-product) which had precipitated
3. filtrationwas filtered off
4. washwashed thoroughly with tetrahydrofuran
5. distillationAfter distilling off the solvent in vacuo
6. distillationa colorless oil passed over on distillation