Reaktion #51476

Reaktionsgleichung

water

1,4-benzodioxane-6-carboxaldehyde

nitromethane

ammonium acetate

→

6-(2-nitroethenyl)-1,4-benzodioxane

Ausbeute 61.0%

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas cooled to ambient temperature
2. 2
   Filtrationthe solid precipitate was collected by filtration
3. 3
   SonstigeThe solid was crystallized from methylene chloride-hexane (1:1, 45 mL)

Vorschrift

To 1,4-benzodioxane-6-carboxaldehyde (10.0 g, 60 mmol) in acetic acid (50 mL) was added nitromethane (6.3 mL, 1.9 eq.) and ammonium acetate (5.1 g, 1.1 eq.). After heating at 110° C. for 4 hours the mixture was cooled to ambient temperature, water (150 mL) was added, and the solid precipitate was collected by filtration. The solid was crystallized from methylene chloride-hexane (1:1, 45 mL) to obtain 7.6 g (61%) of 6-(2-nitroethenyl)-1,4-benzodioxane. To a portion of the solid (3.58 g) dissolved in MeOH-EtOH-AcOEt (1:1:1, 450 mL) was added 10% Pd/C (1.7 g) and concentrated HCl (3.3 mL, 2.3 eq). After shaking on a Parr hydrogenator at 45 psi for 5 hours, the catalyst was removed by filtration through Celite and washed with methanol. Evaporation of the filtrate gave 3.59 g (96%) of 1,4-benzodioxan-6-ethanamine, hydrochloride.

Quelle