Reaktion #54957

Reaktionsgleichung

acetyl chloride

methyl 2-(4-methoxyphenyl)propionate

boron trichloride

→

oil

Methyl 2-(3-acetyl-4-hydroxyphenyl)propionate

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooled in an ice/salt-bath, at a rate sufficient
2. 2
   Temperaturto maintain the temperature between -10° C. and -5° C
3. 3
   Temperaturto maintain the temperature below 0° C
4. 4
   workup.ADDITIONwas added
5. 5
   workup.STIRRINGStirring
6. 6
   workup.WAITwas continued for 1/2 hour at +3° C.
7. 7
   workup.ADDITIONbefore pouring on
8. 8
   Sonstigeto crushed ice/
9. 9
   Einengenconcentrated hydrochloric
10. 10
    Sonstigeseparating the two phases
11. 11
    ExtraktionThe aqueous phase was extracted with ether (3x)
12. 12
    Waschenthe combined organic extracts were washed with saturated sodium bicarbonate solution, saturated brine solution
13. 13
    Trocknendried over anhydrous magnesium sulphate
14. 14
    SonstigeEvaporation of the solvent
15. 15
    Sonstigeyielded the crude product as a pale yellow oil
16. 16
    workup.DISTILLATIONVacuum distillation

Vorschrift

Titanium tetrachloride (82.3 mls) was added dropwise to a stirred solution of methyl 2-(4-methoxyphenyl)propionate (25 g) in dry dichloromethane (250 mls), cooled in an ice/salt-bath, at a rate sufficient to maintain the temperature between -10° C. and -5° C. The mixture was stirred for 10 minutes and acetyl chloride (10 g) was added dropwise at a rate sufficient to maintain the temperature below 0° C. The solution was stirred at -5° C. for 11/2 hours when boron trichloride (15 mls) was added. Stirring was continued for 1/2 hour at +3° C. before pouring on to crushed ice/concentrated hydrochloric and separating the two phases. The aqueous phase was extracted with ether (3x) and the combined organic extracts were washed with saturated sodium bicarbonate solution, saturated brine solution, and dried over anhydrous magnesium sulphate. Evaporation of the solvent yielded the crude product as a pale yellow oil. Vacuum distillation furnished a pale yellow oil bp 120°-125° C./0.15 mm (16.2 g; 59%)

Quelle