Reacción #423995

Ecuación de reacción

fluorine

noscapine

fluoride

→

desired compound ( 3 )

Rendimiento 74.0%

6,7-dimethoxy-isobenzo-furan-1 (3H)-one

Rendimiento 74.0%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONa macroreticular anion-exchange resin containing quaternary ammonium groups
2. 2
   OtroIn Br/F exchange reactions, good yields
3. 3
   Otrowere obtained only when a large molar ratio of the resin with respect to the substrate
4. 4
   Otrofor 12 hours
5. 5
   Filtraciónthe resin was filtered off
6. 6
   Otrothe solvent was removed in vacuo

Procedimiento

Aromatic fluorination of noscapine was achieved by employing the fluoride form of Amberlyst-A 26, a macroreticular anion-exchange resin containing quaternary ammonium groups. The method described [33] for Hal/F exchange may also be applied to other Hal/Hal′ exchange reactions. In Br/F exchange reactions, good yields were obtained only when a large molar ratio of the resin with respect to the substrate was employed. Thus, after refluxing a solution of bromonoscapine in anhydrous THF and an excess of Amberlyst-A 26 (fluorine, polymer-supported, 10 milliequivalents of dry resin; the average capacity of the resin is 4 milliequivalents per gram) for 12 hours, the resin was filtered off and the solvent was removed in vacuo to afford the desired compound (3) in 74% yield. The resin was recovered by washing with 1 N NaOH and then rinsing thoroughly with water until neutrality to generate the hydroxy-form of the resin. It was then stirred overnight with 1 N aqueous hydrofluoric acid, washed with acetone, ether and dried in a vacuum oven at 50° C. for 12 hours to afford the regenerated Amberlyst-A 26 (fluorine, polymer-supported), which can be reused.

Fuente