反应详情

2,5-Diethoxybenzaldehyde (24 g., 0.124 mole) and diethyl malonate (20 g., 0.125 mole) are added to a solution of piperidine (3.0 g.) and glacial acetic acid (6 ml.) in benzene (160 ml.). The mixture is heated under reflux utilizing a Dean-Stark water separator until water ceased to be separated. After 8 hours of distillation 2.3 ml. of water out of a theoretical yield of 2.23 ml. are obtained and the reaction mixture cooled. The cooled reaction mixture is washed with aqueous hydrochloric acid (6 N, 70 ml.) water (70 ml.) and aqueous sodium bicarbonate (5% w/w,50 ml.). The organic layer is separated, dried over magnesium sulfate, filtered, and the solvent removed under reduced pressure to yield a yellow oil (42.7 g., 0.127 mole, 100%). Trituration with petroleum ether yields diethyl 2,5-Diethoxybenzylidenemalonate (38.4 g., 0.114 mole, 92%) m.p. (from petroleum ether) 52°-53° C. I.R.: 1720 cm-1 mass spec m/e 336.

1. temperatureThe mixture is heated
2. temperatureunder reflux
3. customto be separated
4. distillationAfter 8 hours of distillation 2.3 ml
5. customare obtained
6. temperaturethe reaction mixture cooled
7. customThe cooled reaction mixture
8. washis washed with aqueous hydrochloric acid (6 N, 70 ml.) water (70 ml.) and aqueous sodium bicarbonate (5% w/w,50 ml.)
9. customThe organic layer is separated
10. dry with materialdried over magnesium sulfate
11. filtrationfiltered
12. customthe solvent removed under reduced pressure
13. customto yield a yellow oil (42.7 g., 0.127 mole, 100%)