Réaction #3096

Équation de réaction

piperonal

nitromethane

sodium hydroxide

hydrochloric acid

→

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

Rendement 55.0%

Solvants

methanol

—

ice water

water

water

Conditions de réaction

Traitement

1. 1
   Températurewhile maintaining the temperature between 10°-15° C
2. 2
   Températuremaintaining the temperature below 5° C.
3. 3
   AutreA yellow solid precipitated (nitrostyrene)
4. 4
   Filtrationthis was collected by filtration
5. 5
   Lavagewashed with water (1.5 L) until the filtrate
6. 6
   Autredried
7. 7
   Autrerecrystallized from hot ethanol (3 L)

Mode opératoire

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 (1H, d, J=13.5 Hz), 7.47 (1H, d, J=13.5 Hz), 7.09 (1H, dd, J=7.5&2 Hz), 7.01 (1H, d, J=2 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)+.

Source