Reaktion #82849

Reaktionsgleichung

piperonal

nitromethane

sodium hydroxide

hydrochloric acid

→

E-2-(3,4-methylenedioxy)-nitrostyrene

Ausbeute 55.0%

Lösungsmittel

methanol

—

ice water

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwhile maintaining the temperature between 10°-15° C
2. 2
   Temperaturmaintaining the temperature below 5° C.
3. 3
   SonstigeA yellow solid precipitated (nitrostyrene)
4. 4
   Filtrationthis was collected by filtration
5. 5
   Waschenwashed with water (1.5 L) until the filtrate
6. 6
   Sonstigedried
7. 7
   Sonstigerecrystallized from hot ethanol (3 L)

Vorschrift

To a stirred solution of piperonal (75 g, 500 mmol) in methanol (120 mL) at 10° C. was added nitromethane (27.1 mL, 500 mmol, 1 eq) followed by the dropwise addition of sodium hydroxide (21 g, 525 mmol, 1.05 eq) in sufficient water to achieve a total volume of 50 mL while maintaining the temperature between 10°-15° C. The reaction mixture became cloudy, turning to a thick paste. The mixture was stirred for 30 minutes upon completion of the addition, and the mixture was then diluted with ice-water (~350 mL) maintaining the temperature below 5° C., until solution was achieved. The resultant solution was poured in a narrow stream (such that it just failed to break into drops) into a rapidly stirred solution of 36% hydrochloric acid (100 mL)in water (150 mL). A yellow solid precipitated (nitrostyrene), and this was collected by filtration, washed with water (1.5 L) until the filtrate was neutral. The filter cake was air dried and then recrystallized from hot ethanol (3 L) to yield E-2-(3,4-methylenedioxy)-nitrostyrene as yellow needles (53 g, 55%). 1H NMR (300 MHz, CDCl3) δ 7.94 (1 H, d, J=13.5 Hz), 7.47 (1 H, d, J=13.5 Hz), 7.09 (1H, dd, J=7.5&2 Hz), 7.01 (1 H, d, J2 Hz), 6.87 (1H, d, J=7.5 Hz), 6.06 (2H, s). MS (DCl/NH3) m/e 194 (M+H)+, 211 (M+H+NH3)+.

Quelle