反应详情

温度

0 °C

To a solution of 1-(butylcarbamoyl)-1,3-dihydrobenzimidazole-2-thione (39.89 g, 0.16 mole) in 250 mL of chloroform, was added 25.57 g (0.16 mole) of bromine, in 110 mL of chloroform, at 0° C. After the addition was complete, triethylamine (44.6 mL, 0.32 mole), in 80 mL of chloroform, was added dropwise to the reaction mixture. The mixture was stirred at 0° C for an additional 4 h, and then stirred at room temperature for 14 h. The resulting mixture was washed with water and then with a 10% sodium sulfate solution. The organic layer was dried over magnesium sulfate and evaporated to give the crude product. Recrystallization from methanol gave 27.10 g (69%) of 2-butyl-1,2,4-thiadiazolo[4,5-a]benzimidazole-3(2H)-one as colourless crystals: mp 153-154° C. (lit.: 156-157° C., Martin et al. Tetrahedron 1983, 39, 2311).

1. customat 0° C
2. additionAfter the addition
3. stirringstirred at room temperature for 14 h
4. washThe resulting mixture was washed with water
5. dry with materialThe organic layer was dried over magnesium sulfate
6. customevaporated
7. customto give the crude product
8. customRecrystallization from methanol