Reaktion #2045102

Reaktionsgleichung

(E)-3-(4-Ethylphenyl)-2-methyl-2-propen-1-ol

acetic anhydride

pyridine

→

product

(E)-3-(4-Ethylphenyl)-2-methyl-2-propenyl Acetate

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe dichloromethane was removed on a rotary evaporator
2. 2
   workup.DISSOLUTIONthe residue dissolved in EtOAc
3. 3
   WaschenThis solution was washed with aqueous 10% HCl, aqueous 10% NaOH, and saturated aqueous NaCl
4. 4
   TrocknenThe organic phase was dried (MgSO4)
5. 5
   Filtrationfiltered
6. 6
   Einengenconcentrated
7. 7
   SonstigeThe product was purified by silica gel flash chromatography (hexane/EtOAc=80:20)
8. 8
   workup.DISTILLATIONfollowed by Kugelrohr distillation (140-160° C., 0.05 mbar)

Vorschrift

(E)-3-(4-Ethylphenyl)-2-methyl-2-propen-1-ol (4.6 g, 26 1 mmol, obtained by LiAlH4 reduction of (E)-3-(4-ethylphenyl)-2-methyl-2-propenal as described for (E)-2-Ethyl-3-(4-methylphenyl)-2-propen-1-ol) was added to a mixture of acetic anhydride (4.0 g, 39 mmol), pyridine (3.5 g, 44 mmol) and DMAP (0.46 g, 3.7 mmol) in 50 ml of dichloromethane. The mixture was stirred for 20 hours at room temperature. The dichloromethane was removed on a rotary evaporator, and the residue dissolved in EtOAc. This solution was washed with aqueous 10% HCl, aqueous 10% NaOH, and saturated aqueous NaCl. The organic phase was dried (MgSO4), filtered and concentrated. The product was purified by silica gel flash chromatography (hexane/EtOAc=80:20) followed by Kugelrohr distillation (140-160° C., 0.05 mbar) yielding 3.9 g (17.9 mmol, 69% yield) of the product as a colorless oil.

Quelle