Reaktion #44323

Reaktionsgleichung

sodium hydride

4-vinylbenzyl chloride

hexane

n-butyllithium

hydrochloric acid

acetylacetone

→

6-(4-vinylphenyl)-2,4-hexanedione

Ausbeute 56.0%

Lösungsmittel

tetrahydrofuran

THF

hexane dichloromethane

hexamethyl phosphoric triamide

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   Sonstigeto produce colorless precipitate
3. 3
   workup.DISSOLUTIONto dissolve the precipitate
4. 4
   workup.STIRRINGthe mixture was further stirred at 0° C. for 20 minutes
5. 5
   Temperaturthe reaction mixture was warmed back to room temperature
6. 6
   workup.STIRRINGstirred for 20 minutes
7. 7
   WaschenThe organic layer was washed with saturated sodium chloride solution
8. 8
   Trocknendried over magnesium sulfate
9. 9
   workup.DISTILLATIONthe solvent was distilled off
10. 10
    Sonstigea rotary evaporator
11. 11
    SonstigeThe obtained reaction mixture
12. 12
    workup.ADDITIONwas charged in a silica gel column
13. 13
    Sonstigeto separate a main product
14. 14
    workup.DISTILLATIONDistilling off the solvent from the obtained solution

Vorschrift

That is, 1.23 g (60% in oil) (31 mmol) of sodium hydride was weighed in a nitrogen atmosphere and 60 ml of dry tetrahydrofuran (hereinafter abbreviated as THF) was added thereto and the mixture was cooled to 0° C. in an ice bath. To the suspension was dripped a mixed solution of 2.5 g 124 mmol) of acetylacetone and 1 ml of hexamethyl phosphoric triamide to produce colorless precipitate. After stirring the mixture at 0° C. for 10 minutes, 17.5 ml (28 mmol) of a hexane solution (1.6 M) of n-butyllithium was dripped therein to dissolve the precipitate and the mixture was further stirred at 0° C. for 20 minutes. To the obtained pale yellow solution was dripped 4.0 g (26 mmol) of 4-vinylbenzyl chloride and the reaction mixture was warmed back to room temperature and stirred for 20 minutes. Then, dilute hydrochloric acid was added thereto to render the water layer acidic. The organic layer was washed with saturated sodium chloride solution and dried over magnesium sulfate, and the solvent was distilled off by using a rotary evaporator. The obtained reaction mixture was charged in a silica gel column and developed with a mixed solvent of hexane/dichloromethane (1:1 (by volume)) to separate a main product. Distilling off the solvent from the obtained solution afforded 3.0 g (14 mmol) of the objective 6-(4-vinylphenyl)-2,4-hexanedione as a brown liquid. Yield was 56%. Identification was performed by elementary analysis of C and H, and 1H-NMR.

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