反应详情

4-Bromo-3,3-dimethyl-6,6,6-trichlorohexanoic acid (0.8 g.) was added to a stirred solution of sodium (0.2 g.) in dry ethyl alcohol (25 ml.) at the ambient temperature, and the mixture refluxed for 1 hour, during which time a white precipitate was formed. The ethyl alcohol was removed by evaporation under reduced pressure and residual material partitioned between chloroform (10 ml.) and water (25 ml.). The aqueous phase was separated, acidified with concentrated hydrochloric acid to pH 1, and extracted with petroleum ether (boiling range 40° to 60° C., 3×15 ml). The combined petroleum ether extracts were washed with water (10 ml.), dried over anhydrous sodium sulphate, and concentrated by evaporation of the solvent under reduced pressure. The residual oil was purified by preparative thin layer chromatography using silica on glass plates with a methanol (20% by volume) and chloroform (80% by volume) mixture as eluent. 5(2,2-Dichlorovinyl)-4,4-dimethyl-2-oxotetrahydrofuran was obtained as a colourless oil having an Rf ca. 0.8 in the above t.l.c. system, and characterised by mass spectroscopic and infra-red spectral examination (m/e 208).

1. temperaturethe mixture refluxed for 1 hour, during which time a white precipitate
2. customwas formed
3. customThe ethyl alcohol was removed by evaporation under reduced pressure and residual material
4. custompartitioned between chloroform (10 ml.) and water (25 ml.)
5. customThe aqueous phase was separated
6. extractionextracted with petroleum ether (boiling range 40° to 60° C., 3×15 ml)
7. washThe combined petroleum ether extracts were washed with water (10 ml.)
8. dry with materialdried over anhydrous sodium sulphate
9. concentrationconcentrated by evaporation of the solvent under reduced pressure
10. customThe residual oil was purified by preparative thin layer chromatography