反应详情

To a solution of 5.4 g of 3-amino-2-cyano-3-(dimethylamino)propenenitrile and 4.0 g of triethylamine in 25 ml of dimethylformamide at 50° were added 11.6 g of aqueous hydrogen sulfide. Upon complete addition of hydrogen sulfide, the reaction mixture was heated at 65° for 1 hour. Since comparison by thin-layer chromatography of the reaction mixture with the starting material indicated that no reaction had taken place, the reaction temperature was increased to 80°, where it was maintained for two hours, but again no reaction occurred. A small amount of triethylamine and 1 g of hydrogen sulfide were added to the solution. Heating was then continued at 85°. After 30 minutes reaction (as determined by thin-layer chromatography) was 40% complete. Small increments of triethylamine and hydrogen sulfide were added as heating continued until, after 21/2 hours at 85°, reaction was 95% complete. The solution was poured onto 150 ml of ice-water, and was purged with nitrogen gas to remove excess hydrogen sulfide. After 30 minutes, a solid formed, and was collected by filtration. The solid filter cake was washed with cold water and air-dried overnight to give 4.6 g of white solid 3-amino-2-cyano-3-(dimethylamino)propenethioamide, m.p. 186°-187° . The nmr spectrum was consistent with the assigned structure.

1. temperaturethe reaction mixture was heated at 65° for 1 hour
2. temperaturethe reaction temperature was increased to 80°
3. temperaturewhere it was maintained for two hours
4. temperatureHeating
5. customwas then continued at 85°
6. customAfter 30 minutes reaction (as determined by thin-layer chromatography)
7. temperatureas heating
8. custom2 hours
9. customat 85°
10. customreaction
11. customwas purged with nitrogen gas
12. customto remove excess hydrogen sulfide
13. customa solid formed
14. filtrationwas collected by filtration
15. filtrationThe solid filter cake
16. washwas washed with cold water
17. customair-dried overnight