Reacción #323880

Ecuación de reacción

1,2-methylenedioxybenzene

1,2-methylenedioxybenzene

1,2-methylenedioxybenzene

N-methylformanilide

phosgene

→

piperonal

Rendimiento 64.0%

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrokept at 90° C
2. 2
   workup.ADDITIONThe above mixture was added to this reactor over a 5-hour period
3. 3
   workup.ADDITIONAfter completion of the addition
4. 4
   workup.WAITto stand for 1 hour
5. 5
   ExtracciónThen, the resulting mixture was extracted with toluene
6. 6
   workup.DISTILLATIONBy vacuum distillation
7. 7
   Otrothe toluene was removed
8. 8
   workup.DISTILLATIONthe distillate at 84°-85° C./30 mmHg was then collected
9. 9
   workup.DISTILLATIONSubsequently, the distillate at 131°-134° C./10 mmHg was collected

Procedimiento

Into a mixture of 97.6 g (0.80 mole) of 1,2-methylenedioxybenzene and 108 g (0.80 mole) of N-methylformanilide was introduced 87.1 g (0.88 mole) of phosgene at 50° C. over a 1-hour period. Then, the mixture was cooled to 15° C. On the other hand, 29.3 g (0.24 mole) of 1,2-methylenedioxybenzene was charged into another reactor and kept at 90° C. The above mixture was added to this reactor over a 5-hour period. After completion of the addition, the reaction mixture was kept at 90° C. for 30 minutes, poured into ice water, and allowed to stand for 1 hour. Then, the resulting mixture was extracted with toluene. By vacuum distillation, the toluene was removed and the distillate at 84°-85° C./30 mmHg was then collected to recover 63.4 g (0.52 mole) of unreacted 1,2-methylenedioxybenzene. Subsequently, the distillate at 131°-134° C./10 mmHg was collected to obtain 76.8 g (0.512 mole) of piperonal having a purity of 99.5%. The yield (expressed in terms of mole percentage based on the amount of N-methylformanilide used) and selectivity (expressed in terms of mole percentage based on the amount of 1,2-methylenedioxybenzene having reacted) of piperonal were 64.0% and 98.5%, respectively. This product had a melting point of 37° C.

Fuente