反应详情

温度

140 °C

During 10 min. (4-chloro-benzyl)-[2,2-dimethoxy-1-methyl-eth-(Z)-ylidene]-amine (120 g, 0.496 mol) was added dropwise to polyphosphoric acid (1000 g) at 130° C. The resulting reaction mixture was heated for 3 h at 140° C. After cooling below 100° C. the reaction mixture was poured onto ice (1 kg) and neutralized (pH=7) with a 33% aqueous NaOH solution. Care was taken that the temperature did not rise above 35° C. by adding additional ice. The reaction mixture was extracted with dichloromethane (3×1 L) and the combined organic layers were dried over Na2SO4, filtered and concentrated at reduced pressure to afford a black oil. The crude product was purified bulb-to-bulb distillation (105-110° C., 2 mbar) to afford the title compound as colorless oil which crystallized upon standing (66.7 g, 0.375 mol, 76%). MS (ES+): 178 (M(C10H835ClN)+H)+.

1. customThe resulting reaction mixture
2. temperatureAfter cooling below 100° C. the reaction mixture
3. customdid not rise above 35° C.
4. additionby adding additional ice
5. extractionThe reaction mixture was extracted with dichloromethane (3×1 L)
6. dry with materialthe combined organic layers were dried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated at reduced pressure
9. customto afford a black oil
10. customThe crude product was purified
11. distillationbulb-to-bulb distillation (105-110° C., 2 mbar)