Reaktion #87864

Reaktionsgleichung

Hydrochloric acid

3-bromo-4-isopropylaniline

3-Bromo-4-Isopropylaniline

sodium nitrite

hydrochloric acid

→

2-Bromo-4-chloro-1-isopropylbenzene

Ausbeute 62.3%

Lösungsmittel

water

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGAfter stirring for another 1.5 hours
2. 2
   Extraktionthe mixture was extracted with dichloromethane (250 g)
3. 3
   Sonstigethe phases were separated
4. 4
   workup.DISTILLATIONdichloromethane was distilled off under reduced pressure
5. 5
   SonstigeThe crude product obtained
6. 6
   workup.DISTILLATIONwas purified by distillation

Vorschrift

Hydrochloric acid (152 g, 31% strength, 1.29 mol) was added dropwise to a suspension of 3-bromo-4-isopropylaniline (VII) (100 g, 0.43 mol) and water (150 g) at room temperature. The suspension was subsequently cooled to 5° C. and a solution of sodium nitrite (32.7 g, 0.46 mol) in water (140 g) was added dropwise over a period of 2 hours. After stirring for another 1 hour, amidosulphuric acid (2.5 g, 0.026 mol) was added. Copper(I) chloride (10.8 g, 0.11 mol), hydrochloric acid (202 g, 31%, 1.72 mol) and water (75 g) were placed in a second flask and the diazonium salt generated previously was added dropwise over a period of 30 minutes. After stirring for another 1.5 hours, the mixture was extracted with dichloromethane (250 g), the phases were separated and dichloromethane was distilled off under reduced pressure. The crude product obtained was purified by distillation. 2-Bromo-4-chloro-1-isopropylbenzene (62.6 g, 94.8 GC-% by area. 59% of theory) was obtained as a colourless oil.

Quelle