反应详情

温度

-50 °C

4,4,4-Trifluoro-3-(methylamino)-2-butenoic acid, ethyl ester, (2Z)-(1.43 g) in toluene (25 ml) was slowly added to a stirred suspension of sodium hydride (60%, 0.28 g) in anhydrous N,N-dimethylformamide (25 ml) at −10° C. The solution was stirred for 0.5 hr at this temperature and cooled to −50° C. The above isothiocyanate dissolved in toluene (25 ml) was added drop wise with stirring to the solution, while maintaining the temperature at −50° C. The solution was then allowed to warm to −20° C. and stirred for 2 hr. After neutralization with dilute hydrochloric acid, the solution was partitioned between water and ethyl acetate and the organic layer was evaporated to furnish a crude product. Column chromatography over silica gel (eluent, hexane:ethyl acetate, 90:10) afforded the title compound (2.6 g). 1H NMR, CDCl3, 3.86 (3H, m), 5.74 (2H, s), 6.51 (1H, s), 7.27-7.30 (3H, m), 7.42-7.46 (2H, m).

1. additionwas added drop wise
2. stirringwith stirring to the solution
3. temperaturewhile maintaining the temperature at −50° C
4. temperatureto warm to −20° C.
5. stirringstirred for 2 hr
6. customAfter neutralization with dilute hydrochloric acid, the solution was partitioned between water and ethyl acetate
7. customthe organic layer was evaporated
8. customto furnish a crude product