反应详情

At 0° C., a solution of 36 g (299 mmol) of 9-borabicyclo[3.3.1]nonane in 600 ml of tetrahydrofuran is added over a period of 45 min to 37 g (136 mmol) of the compound from Example 20A. After a further hour at this temperature, a solution of 27 g (680 mmol) of sodium hydroxide (1N in water) is added over the course of 15 min. The mixture is stirred for a further 5 min, and 125 ml of a 30% strength hydrogen peroxide solution are then added such that the temperature does not exceed 30° C. Cooling is removed, and the mixture is stirred for another 30 min. The mixture is extracted repeatedly with ethyl acetate, the combined organic phases are washed with a solution of 730 g (1.50 mol) of sodium disulphite, the organic phase is separated off and the aqueous phase is reextracted with ethyl acetate. The combined organic phases are washed with saturated sodium chloride solution, dried over magnesium sulphate and evaporated to dryness under reduced pressure. The residue is absorbed on silica gel and chromatographed using a gradient of cyclohexane and ethyl acetate. The product fractions are combined and evaporated to dryness under reduced pressure. For crystallization, tert-butyl methyl ether is added. The crystals are filtered off and dried under reduced pressure. This gives 24 g (60% of theory) of the desired product.

1. waitAfter a further hour at this temperature
2. customdoes not exceed 30° C
3. temperatureCooling
4. customis removed
5. stirringthe mixture is stirred for another 30 min
6. extractionThe mixture is extracted repeatedly with ethyl acetate
7. customthe organic phase is separated off
8. washThe combined organic phases are washed with saturated sodium chloride solution
9. dry with materialdried over magnesium sulphate
10. customevaporated to dryness under reduced pressure
11. customThe residue is absorbed on silica gel
12. customchromatographed
13. customevaporated to dryness under reduced pressure
14. customFor crystallization, tert-butyl methyl ether
15. additionis added
16. filtrationThe crystals are filtered off
17. customdried under reduced pressure