Реакция #2665

Уравнение реакции

5-chloro vanillin

boron tribromide

→

expected product

Выход 77.3%

3-chloro-4,5-dihydroxy benzaldehyde

Выход 77.3%

Растворители

dichloromethane

dichloromethane

Условия реакции

Обработка

1. 1
   workup.WAITthe mixture stood for one night at ambient temperature
2. 2
   КонцентрированиеIt was concentrated
3. 3
   Температураcooled again to 0° C.
4. 4
   ДругоеThe crystallized product was separated
5. 5
   Промывкаwashed with water
6. 6
   Другоеdried
7. 7
   Другоеcrystallized from an isopropanol- water mixture (1-2 by volume)

Методика

37.2 g of commercial 5-chloro vanillin and 800 ml of dichloromethane were mixed together under nitrogen and cooled to 0° C. 300 ml of a molar solution of boron tribromide in dichloromethane are added and the mixture stood for one night at ambient temperature. It was concentrated, cooled again to 0° C. and acidified. The crystallized product was separated, washed with water, dried and crystallized from an isopropanol- water mixture (1-2 by volume) to obtain 26.6 g of the expected product melting at >260° C.

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