反应详情

温度

20 °C

To 12.5 mL of water was added 8.73 g (0.0873 mole) of chromium trioxide which was mixed until all solid had dissolved. This solution was immersed in an ice/water bath, and 13.4 g (7.3 mL, 0.137 mole) of concentrated sulfuric acid (18M) was added cautiously. This was followed by the addition of 25 mL of water. The solution was then cooled to 0°-5° C. and added to a stirred solution of 16.5 g (0.125 mole) of 4,4-dimethyl-4-silapentanol in 800 mL of acetone which had been cooled to 0°-10° C. in an ice/water bath. During the addition the temperature was maintained at 20° C., and stirring was continued for three hours after the addition was complete. At the conclusion of this period sodium bisulfite was added to the reaction mixture in small portions until the brown color of chromic acid had disappeared from the upper layer. The two layers were separated, and the dense, green lower layer was extracted with 200 mL of petroleum ether. The layers were separated, and the upper layer was added to the upper layer which had been previously separated. This caused two phases to form. The layers were separated, and the lower layer was added to the lower layer from the reaction mixture. The combined lower layers were extracted three times with 200 mL of petroleum ether. The extracts were combined with the previously separated petroleum ether extract, and this mixture was successively washed twice with a saturated aqueous solution of sodium chloride, twice with a saturated aqueous solution of sodium bicarbonate, and finally with a saturated aqueous solution of sodium chloride. After being dried over anhydrous magnesium sulfate, the solvent was evaporated from the combined extracts under reduced pressure, leaving 4,4-dimethyl-4-silapentanoic acid as a residue. The NMR spectrum was consistent with the proposed structure. This is the method described in Organic Synthesis, Vol. V, p 866.

1. additionwas mixed until all solid
2. dissolutionhad dissolved
3. customThis solution was immersed in an ice/water bath
4. temperatureThe solution was then cooled to 0°-5° C.
5. temperaturehad been cooled to 0°-10° C. in an ice/water bath
6. additionDuring the addition the temperature
7. additionafter the addition
8. customThe two layers were separated
9. extractionthe dense, green lower layer was extracted with 200 mL of petroleum ether
10. customThe layers were separated
11. additionthe upper layer was added to the upper layer which
12. customhad been previously separated
13. customto form
14. customThe layers were separated
15. additionthe lower layer was added to the lower layer from the reaction mixture
16. extractionwere extracted three times with 200 mL of petroleum ether
17. extractionextract
18. washthis mixture was successively washed twice with a saturated aqueous solution of sodium chloride, twice with a saturated aqueous solution of sodium bicarbonate
19. dry with materialAfter being dried over anhydrous magnesium sulfate
20. customthe solvent was evaporated from the combined extracts under reduced pressure