반응 #361711

반응 방정식

5-cyano-3,4-dimethoxy-4'-(trifluoromethyl)benzophenone

boron tribromide

methanol

→

5-cyano-3,4-dihydroxy-4'-(trifluoromethyl)benzophenone

용매

methylene chloride

반응 조건

후처리

1. 1
   온도The mixture is heated
2. 2
   온도under reflux for an additional 4 hours
3. 3
   workup.STIRRINGstirred at room temperature for 2 hours
4. 4
   기타evaporated
5. 5
   기타the residue is dried in vacuo
6. 6
   기타partitioned between ethyl acetate and ice-water
7. 7
   추출The aqueous phase is extracted twice more with ethyl acetate
8. 8
   건조The combined ethyl acetate phases are dried over sodium sulfate
9. 9
   기타evaporated
10. 10
    workup.STIRRINGThe thus-obtained material is stirred at 130° for 6 hours with 10 ml of acetic anhydride and 1 ml of pyridine
11. 11
    기타The mixture is evaporated
12. 12
    기타the residue is partitioned between ice-water and methylene chloride
13. 13
    건조The methylene chloride phase is dried over sodium sulfate
14. 14
    기타evaporated
15. 15
    기타the residue is chromatographed on 30 g of silica gel with methylene chloride
16. 16
    workup.DISSOLUTIONThe thus-obtained diacetate is dissolved in 10 ml of methanol
17. 17
    workup.ADDITIONThe solution is treated with 4.2 ml of 1N sodium hydroxide solution
18. 18
    workup.STIRRINGstirred at 0° for 1 hour
19. 19
    기타evaporated
20. 20
    기타partitioned between ethyl acetate and saturated sodium chloride solution
21. 21
    건조The ethyl acetate phases are dried over sodium sulfate
22. 22
    기타evaporated
23. 23
    기타the residue is recrystallized from methylene chloride

실험 절차

1.5 g of 5-cyano-3,4-dimethoxy-4'-(trifluoromethyl)benzophenone (dissolved in 75 ml of methylene chloride) are treated at 5° with 2.18 ml of boron tribromide, whereupon the mixture is stirred at room temperature for 18 hours. The reaction mixture is subsequently diluted with 50 ml of methylene chloride. The mixture is heated under reflux for an additional 4 hours, treated at -70° with 15 ml of methanol, stirred at room temperature for 2 hours, evaporated, the residue is dried in vacuo and partitioned between ethyl acetate and ice-water. The aqueous phase is extracted twice more with ethyl acetate. The combined ethyl acetate phases are dried over sodium sulfate and evaporated. The thus-obtained material is stirred at 130° for 6 hours with 10 ml of acetic anhydride and 1 ml of pyridine. The mixture is evaporated and the residue is partitioned between ice-water and methylene chloride. The methylene chloride phase is dried over sodium sulfate and evaporated, and the residue is chromatographed on 30 g of silica gel with methylene chloride. The thus-obtained diacetate is dissolved in 10 ml of methanol. The solution is treated with 4.2 ml of 1N sodium hydroxide solution, stirred at 0° for 1 hour, neutralized with acetic acid, evaporated and partitioned between ethyl acetate and saturated sodium chloride solution. The ethyl acetate phases are dried over sodium sulfate and evaporated, and the residue is recrystallized from methylene chloride. There is obtained 5-cyano-3,4-dihydroxy-4'-(trifluoromethyl)benzophenone of melting point 204°-206°.

출처