反应详情

A solution of 11.4 grams (0.030 mole) of methyl 6-chloro-2-methyl-3-[1-methyl-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedion-3-yl]benzoate and 5.4 grams (0.030 mole) of NBS in the presence of 0.03 gram of benzoyl peroxide in 250 mL of carbon tetrachloride was irradiated with a sun lamp as it stirred at reflux for about 18 hours. The reaction mixture was then cooled and washed with water. The organic layer was dried with magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure to a residue. The residue was subjected to NMR analysis, which indicated that the reaction was about 15% complete. The residue was recharged to the reaction vessel and treated with the same amounts of NBS, benzoyl peroxide, and carbon tetrachloride under the same conditions as described above. Upon completion of the second 18 hour reflux period, a small sample was washed with water, dried with magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure to a residue. The residue was subjected to NMR analysis, which indicated that the reaction was about 70% complete. An additional 2.0 grams (0.011 mole) of NBS was added, and the solution was irradiated at reflux for an additional 18 hours. The reaction mixture was then cooled and washed with water. The organic layer was dried with magnesium sulfate, filtered, and concentrated under reduced pressure to a residue. The residue was purified by column chromatography on silica gel, and the fractions containing product were combined and concentrated under reduced pressure, yielding 11.0 grams of subject compound. The NMR spectrum was consistent with the proposed structure.

1. temperatureat reflux for about 18 hours
2. temperatureThe reaction mixture was then cooled
3. washwashed with water
4. dry with materialThe organic layer was dried with magnesium sulfate
5. filtrationfiltered
6. concentrationThe filtrate was concentrated under reduced pressure to a residue
7. additiontreated with the same amounts of NBS, benzoyl peroxide, and carbon tetrachloride under the same conditions
8. temperatureUpon completion of the second 18 hour reflux period
9. washa small sample was washed with water
10. dry with materialdried with magnesium sulfate
11. filtrationfiltered
12. concentrationThe filtrate was concentrated under reduced pressure to a residue
13. customthe solution was irradiated
14. temperatureat reflux for an additional 18 hours
15. temperatureThe reaction mixture was then cooled
16. washwashed with water
17. dry with materialThe organic layer was dried with magnesium sulfate
18. filtrationfiltered
19. concentrationconcentrated under reduced pressure to a residue
20. customThe residue was purified by column chromatography on silica gel
21. additionthe fractions containing product
22. concentrationconcentrated under reduced pressure