Реакция #45644

Уравнение реакции

trimethylsilyldiazomethane

water

tetrafluoroboric acid

tetrafluoroboric acid

trimethylsilyldiazomethane

6-Bromo-7-fluoro-2-(2-hydroxy-1,1-dimethylethyl)-5-methyl-1,3-benzoxazole-4-carbonitrile

→

compound

Выход 106.1%

6-Bromo-2-[2-methoxy-1,1-dimethylethyl]-7-fluoro-5-methyl-1,3-benzoxazole-4-carbonitrile

Выход 106.1%

Растворители

methylene chloride

Условия реакции

Обработка

1. 1
   workup.ADDITIONwere dropwise added
2. 2
   workup.STIRRINGby stirring for 19 hours
3. 3
   Температураwith heating up to room temperature
4. 4
   ДругоеAfter the reaction
5. 5
   Другоеthe two reaction solutions
6. 6
   Экстракцияfollowed by extraction with ethyl acetate
7. 7
   Промывкаwashing with saturated brine
8. 8
   СушкаThe obtained organic layer was dried over anhydrous sodium sulfate
9. 9
   Другоеthe solvent was evaporated away under reduced pressure
10. 10
    Промывкаeluted with a mixed solvent of n-hexane/ethyl acetate (10:1

Методика

6-Bromo-7-fluoro-2-(2-hydroxy-1,1-dimethylethyl)-5-methyl-1,3-benzoxazole-4-carbonitrile (I-108) (912.6 mg, 2.79 mmol) and (514 mg, 1.57 mmol) were separately dissolved in methylene chloride (9 ml and 5 ml), and aqueous 42% tetrafluoroboric acid solution (420 μl, 2.79 mmol) and (240 μl, 1.57 mmol) were individually added to each, then with cooling with ice, trimethylsilyldiazomethane (2 M hexane solution, 2.8 ml, 5.58 mmol) and (1.6 ml, 3.14 mmol) were dropwise added, followed by stirring at 0° C. for 40 minutes; but since the reaction did not finish, the same amount of aqueous 42% tetrafluoroboric acid solution and trimethylsilyldiazomethane were added, followed by stirring for 19 hours with heating up to room temperature. After the reaction, the two reaction solutions were combined, water was added, followed by extraction with ethyl acetate and washing with saturated brine. The obtained organic layer was dried over anhydrous sodium sulfate, the solvent was evaporated away under reduced pressure. The resulting residue was subjected to silica gel column chromatography, and eluted with a mixed solvent of n-hexane/ethyl acetate (10:1, v/v) to obtain the entitled compound (1.01 g, 68%) as a white solid.

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