反应详情

0.35 mol diphosgene is added dropwise over 1 hour to a mixture of 0.28 mol of methyl 2-amino-4-pentenoate, prepared as described by D. Ferroud, J. P. Genet, and R. Kiolle in Tetrahedron Letters, 1986, 27, 23-26, and 0.4 g activated charcoal in 400 mL dioxane under N2. The reaction mixture is then heated and stirred at reflux for 21/2 hours. The reaction mixture is then cooled, filtered, and concentrated to dryness by rotary evaporator, keeping exposure to moisture to a minimum. The crude product is re-dissolved in 100 mL THF, and the pH of the solution is adjusted to 5.5-6.0 by addition of pyridine. The product mixture is again filtered, and the product is purified by fractional distillation to give methyl 2-isocyanato-4-pentenoate.

1. customprepared
2. temperatureThe reaction mixture is then heated
3. temperatureat reflux for 21/2 hours
4. temperatureThe reaction mixture is then cooled
5. filtrationfiltered
6. concentrationconcentrated to dryness by rotary evaporator
7. dissolutionThe crude product is re-dissolved in 100 mL THF
8. additionthe pH of the solution is adjusted to 5.5-6.0 by addition of pyridine
9. filtrationThe product mixture is again filtered
10. distillationthe product is purified by fractional distillation