反应详情

温度

140 °C

430 ml of toluene and 40 ml (349 mmol) of 99% pure 4-aminobenzylamine are introduced into a four-neck flask with mechanical paddle stirrer, water trap and reflux condenser. A two-phase mixture is obtained owing to the low solubility of the amine. 96 ml (775 mmol) of 98% pure anisaldehyde are added, and the mixture is heated with an oil bath heated to 140° C. In the heating-up phase, the reaction mixture starts to boil at around 80° C., and cloudy water/toluene azeotrope distills into the water trap. After about 30 min, the maximum internal temperature is 114° C., and only clear toluene now distills over. 12.5 ml of water (corresponding to about 100% of theory of the two equivalents of water) separate out. A TLC check (plate deactivated by previously standing in NEt3(triethylamine) vapor-saturated tank, ethyl acetate/n-heptane 1:1 plus 1% NEt3) indicates complete conversion of the 4-aminobenzylamine. The mixture is actively cooled to room temperature. A mixture of 800 ml of n-heptane and 200 ml of ethyl acetate is then run slowly in, during which, after addition of only about 200 ml, a pale yellow precipitate separates out spontaneously. The mixture is stirred for 1 h, and the precipitate is filtered off with suction and dried under HV. Yield: 105.6 g.

1. temperaturereflux condenser
2. customA two-phase mixture is obtained
3. temperaturethe mixture is heated with an oil bath
4. customto boil at around 80° C.
5. distillationcloudy water/toluene azeotrope distills into the water trap
6. customis 114° C.
7. distillationonly clear toluene now distills over
8. temperatureThe mixture is actively cooled to room temperature
9. additionafter addition of only about 200 ml
10. filtrationthe precipitate is filtered off with suction
11. customdried under HV