Reaktion #2666

Reaktionsgleichung

5-nitro vanillin

boron tribromide

→

expected product

Ausbeute 55.4%

3-nitro-4,5-dihydroxy benzaldehyde

Ausbeute 55.4%

Lösungsmittel

dichloromethane

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Einengenwas concentrated
2. 2
   workup.WAITleft for 16 hours at ambient temperature
3. 3
   ExtraktionExtraction
4. 4
   Waschenthe organic phase was washed
5. 5
   Sonstigedried
6. 6
   Einengenconcentrated

Vorschrift

35 g of 5-nitro vanillin (commercial) and 1200 ml of dichloromethane were mixed together under nitrogen and the mixture was cooled to 0° C. 533 ml of a molar solution of boron tribromide in dichloromethane were added and the mixture stood for 2 days at abmient temperature and then was concentrated. The residue was taken up cold (ice bath+methanol) in 300 ml of 2N hydrochloric acid and the mixture was stirred for two to three hours at this temperature, then left for 16 hours at ambient temperature. Extraction was carried out with ethyl acetate and the organic phase was washed, dried and concentrated to obtain 18 g of the expected product melting at >260° C.

Quelle