Реакция #40924

Уравнение реакции

Maleimide

4-(trifluoromethyl)aniline

sodium nitrite

sodium acetate

hydrochloric acid

→

title compound

Выход 69.0%

3-[4-(trifluoromethyl)phenyl]-1H-pyrrole-2,5-dione

Выход 69.0%

Растворители

acetone

water

water

Условия реакции

Обработка

1. 1
   workup.STIRRINGto stir for further 30 minutes
2. 2
   Другоеwas reduced to 0° C.
3. 3
   ДругоеAt the end of diazotisation, a clear yellow solution was obtained
4. 4
   workup.WAITAfter a few minutes a gas started
5. 5
   workup.STIRRINGto stir at 0° C. for 1 h and overnight at room temperature
6. 6
   ДругоеAcetone was removed in vacuo
7. 7
   Фильтрацияthe residue was filtered
8. 8
   Другоеdried overnight in vacuo

Методика

A mixture of hydrochloric acid (37% in water, 285 mL) and water (190 mL) was added to 4-(trifluoromethyl)aniline (150 g, 116 mL) at room temperature with vigorous stirring and the formed precipitate was allowed to stir for further 30 minutes. Temperature was reduced to 0° C. and sodium nitrite (70.6 g) in 180 mL of water was added dropwise to the stirred suspension. At the end of diazotisation, a clear yellow solution was obtained. Maleimide (180 g) in acetone (1.1 L) was added dropwise at 0° C. and then the pH of the solution was adjusted to 3-3.5 by adding sodium acetate. Copper (II) chloride (18.8 g) was added to the vigorously stirred mixture. After a few minutes a gas started to develop (conspicuous foaming). The reaction mixture was allowed to stir at 0° C. for 1 h and overnight at room temperature. Acetone was removed in vacuo, the residue was filtered and dried overnight in vacuo to give the title compound (155 g) as a light brown solid.

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