反应详情

36 ml. (0.465 mole) of N,N-dimethylformamide were stirred at 0° and 36 ml. (0.392 mole) of phosphorus oxychloride were added dropwise (a salt/ice bath was used in order to keep the reaction mixture at 0°). To the stirring semi-solid, faintly colored reaction mixture was added 300 ml. of 1,2-dichloroethane. Upon warming to room temperature by means of a water bath (25°), a clear solution resulted which was cooled to -7° with an icesalt bath. A solution of 30 ml. (0.293 mole) of β-dimethylaminoacrylonitrile in 90 ml. of 1,2-dichloroethane was added dropwise keeping the temperature between -4° to -7°. The addition required about 1 hour. The cooling bath was removed and the clear amber reaction mixture allowed to come to room temperature. The reaction mixture was transferred to a 2 liter, round bottomed flask and the solvent removed in vacuo leaving a semi-solid orange colored residue. A 100 g. of ice was added to the residue which gradually dissolved with evolution of heat. The solution was transferred to a beaker and the pH adjusted to 8.4 by adding carefully 2N sodium hydroxide (815 ml. were required) to the stirred solution at 15°-20°. The resulting solution was extracted with ethyl acetate in a liquid-liquid extractor overnight. The ethyl acetate extract was cooled, the crystals which had separated were filtered off, washed with cold ethyl acetate and dried in vacuo, affording crude 2-cyano-3-dimethylaminoacrolein, as deep yellow prisms, m.p. 143°-144°. This material was dissolved in 500 ml. of hot water, treated with 2 g. of norite, the solvent removed in vacuo and the residue crystallized from absolute ethanol, producing the pure product in the form of light yellow prisms, m.p. 143°-144°.

1. customat 0°
2. additionTo the stirring semi-solid, faintly colored reaction mixture was added 300 ml
3. customa clear solution resulted which
4. temperaturewas cooled to -7° with an icesalt bath
5. custombetween -4° to -7°
6. additionThe addition required about 1 hour
7. customThe cooling bath was removed
8. customthe clear amber reaction mixture
9. customto come to room temperature
10. customthe solvent removed in vacuo
11. customleaving a semi-solid orange colored residue
12. additionof ice was added to the residue which
13. dissolutiongradually dissolved with evolution
14. temperatureof heat
15. extractionThe resulting solution was extracted with ethyl acetate in a liquid-liquid extractor overnight
16. extractionThe ethyl acetate extract
17. temperaturewas cooled
18. customthe crystals which had separated
19. filtrationwere filtered off
20. washwashed with cold ethyl acetate
21. customdried in vacuo