反应详情

To a stirred solution of 12.8 grams (0.07 mole) of 3,5-dichloro-4H-1,2,6-thiadiazin-4-one and 6.7 grams (0.07 mole) of 3-hydroxypyridine in 300 ml of tetrahydrofuran was added dropwise 7.1 grams (0.07 mole) of triethylamine. During the addition the exothermic reaction caused the reaction mixture temperature to rise to 34° C. Upon complete addition, the reaction mixture was stirred for 16 hours during which time it cooled to ambient temperature. The reaction mixture was filtered to remove triethylamine hydrochloride. The filter cake was washed with tetrahydrofuran. The filtrate and wash were combined and evaporated under reduced pressure to a residual solid. The residue was triturated with 300 ml of distilled water and the insolubles collected by filtration. The filter cake was washed with water and recrystallized twice from ethanol. A sample of the recrystallized solid was dissolved in chloroform and subjected to analysis by thin layer chromatography. This analysis indicated that the solid contained impurities. The filtrates from the recrystallizations were combined and evaporated under reduced pressure to a residue. The residue was combined with the twice-recrystallized solid and dissolved in chloroform. The solution was slurried with silica gel in an effort to remove the impurities. The mixture was filtered and the filtrate was evaporated under reduced pressure to a residual solid. The solid was recrystallized from ethanol to give 7.0 grams (42%) of 3-chloro-5-(3-pyridyloxy)-4H-1,2,6-thiadiazin-4-one; m.p. 134.5°-135.5° C.

1. additionDuring the addition
2. customthe exothermic reaction
3. customto rise to 34° C
4. additionUpon complete addition
5. filtrationThe reaction mixture was filtered
6. customto remove triethylamine hydrochloride
7. washThe filter cake was washed with tetrahydrofuran
8. washThe filtrate and wash
9. customevaporated under reduced pressure to a residual solid
10. distillationThe residue was triturated with 300 ml of distilled water
11. filtrationthe insolubles collected by filtration
12. washThe filter cake was washed with water
13. customrecrystallized twice from ethanol
14. dissolutionA sample of the recrystallized solid was dissolved in chloroform
15. customThe filtrates from the recrystallizations
16. customevaporated under reduced pressure to a residue
17. dissolutiondissolved in chloroform
18. customto remove the impurities
19. filtrationThe mixture was filtered
20. customthe filtrate was evaporated under reduced pressure to a residual solid
21. customThe solid was recrystallized from ethanol