Reaktion #6992

Reaktionsgleichung

5-bromo-2-(3,4-dichlorophenoxy)-benzaldehyde

DMF

→

title product

5-CYANO-2-(3,4-DICHLOROPHENOXY)-BENZALDEHYDE

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeUnder N2 in a flame-dried 3-neck round bottomed flask fitted with a reflux condenser and magnetic stirrer
2. 2
   Sonstigewhile degassing with N2 for 5 min
3. 3
   TemperaturAfter heating at approximately 80° C. for 90 min.
4. 4
   Temperaturto cool to room temperature
5. 5
   workup.ADDITIONThe reaction mixture was then diluted with water and ethyl acetate (EA)
6. 6
   workup.STIRRINGstirred another 10 min
7. 7
   SonstigeThe water layer was separated
8. 8
   Extraktionextracted twice with EA
9. 9
   Waschenwashed with an aqueous solution of Rochelle salt (potassium sodium tartrate tetrahydrate)
10. 10
    TrocknenThe organic layer was dried with Na2SO4
11. 11
    Filtrationfiltered
12. 12
    Einengenconcentrated in vacuo to an oil
13. 13
    Sonstigechromatographed on a 15×5 cm column of silica gel
14. 14
    Wascheneluting with CH2Cl2:hexanes (1:1)

Vorschrift

Under N2 in a flame-dried 3-neck round bottomed flask fitted with a reflux condenser and magnetic stirrer, a mixture of 5-bromo-2-(3,4-dichlorophenoxy)-benzaldehyde (3.0 g, 8.7 mmol), zinc (II) cyanide (1.5 g, 13 mmol) and tetrakis(triphenylphosphine)palladium (0) (1.5 g, 1.3 mmol) in anhydrous DMF (145 ml) was stirred at room temperature while degassing with N2 for 5 min. After heating at approximately 80° C. for 90 min., the reaction was judged complete by thin layer chromatography (50% CH2Cl2:hexanes) and was allowed to cool to room temperature. The reaction mixture was then diluted with water and ethyl acetate (EA) and stirred another 10 min. The water layer was separated, extracted twice with EA and combined with the original EA layer, and washed with an aqueous solution of Rochelle salt (potassium sodium tartrate tetrahydrate) followed by aqueous NaCl. The organic layer was dried with Na2SO4, filtered and concentrated in vacuo to an oil. The oil was flash chromatographed on a 15×5 cm column of silica gel, eluting with CH2Cl2:hexanes (1:1) to obtain the title product as a white solid, 1.5 g (60%), m.p. 122–126° C.

Quelle