反应详情

A suspension of 5.5 grams (0.144 mole) of lithium aluminum hydride in 300 mL of diethyl ether was stirred, and 25.0 grams (0.111 mole) of 2,3,5-trichlorobenzoic acid in 200 mL of diethyl ether was added dropwise at a rate which maintained a gentle reflux. The complete addition required about 75 minutes. Upon completion of addition, the reaction was mixture heated at reflux for 4.5 hours. After this time the reaction mixture was stirred for about 16 hours, during which time it was allowed to cool to ambient temperature. The reaction mixture was then cooled to below 10° C., and 6 mL of water was added slowly dropwise. Upon completion of addition, 5 mL of aqueous 20% sodium hydroxide was added dropwise, followed by an additional 12 mL of water added dropwise. The reaction mixture was then stirred for 20 minutes and filtered through diatomaceous earth. The filtrate was concentrated under reduced pressure to a residue. The residue was stirred into water, and the combination was extracted with ethyl acetate. The extracts were combined and washed with three portions of water. The organic layer was dried with sodium sulfate and filtered. The filtrate was concentrated under reduced pressure, yielding 17.1 grams of 2,3,5-trichlorophenylmethanol. The NMR spectrum was consistent with the proposed structure.

1. temperaturemaintained a gentle reflux
2. additionThe complete addition required about 75 minutes
3. additionUpon completion of addition
4. temperatureheated
5. temperatureat reflux for 4.5 hours
6. stirringAfter this time the reaction mixture was stirred for about 16 hours, during which time it
7. temperatureThe reaction mixture was then cooled to below 10° C.
8. additionwas added dropwise
9. additionadded dropwise
10. stirringThe reaction mixture was then stirred for 20 minutes
11. filtrationfiltered through diatomaceous earth
12. concentrationThe filtrate was concentrated under reduced pressure to a residue
13. stirringThe residue was stirred into water
14. extractionthe combination was extracted with ethyl acetate
15. washwashed with three portions of water
16. dry with materialThe organic layer was dried with sodium sulfate
17. filtrationfiltered
18. concentrationThe filtrate was concentrated under reduced pressure