Reacción #54958

Ecuación de reacción

acetyl chloride

methyl 2-(4-methoxyphenyl)propionate

boron trichloride

→

oil

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

Disolventes

dichloromethane

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturacooled in an ice/salt-bath, at a rate sufficient
2. 2
   Temperaturato maintain the temperature between -10° C. and -5° C
3. 3
   Temperaturato 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
   Otroto crushed ice/concentrated hydrochloric acid
9. 9
   Otroseparating the two phases
10. 10
    ExtracciónThe aqueous phase was extracted with ether (3x)
11. 11
    Lavadothe combined organic extracts were washed with saturated sodium bicarbonate solution, saturated brine solution
12. 12
    Secadodried over anhydrous magnesium sulphate
13. 13
    OtroEvaporation of the solvent
14. 14
    Otroyielded the crude product as a pale yellow oil
15. 15
    workup.DISTILLATIONVacuum distillation

Procedimiento

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 acid 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%)

Fuente