Reaction #487553

Reaction equation

sodium nitrite

hydrobromic acid

4-ethyl-3-nitroaniline

Hydrobromic acid

→

4-bromo-1-ethyl-2-nitrobenzene

Solvents

water

water

Conditions

Workup

1. 1
   workup.DISSOLUTIONdissolves
2. 2
   Temperaturemaintaining the temperature at 0-5° C
3. 3
   workup.ADDITIONOnce the addition
4. 4
   Otherthe cooling bath is removed
5. 5
   workup.STIRRINGthe reaction mixture is stirred for one hour at room temperature
6. 6
   workup.STIRRINGThe reaction mixture is stirred
7. 7
   Temperatureto warm to room temperature over three hours
8. 8
   ExtractionThe mixture is extracted with diethyl ether
9. 9
   Dryingdried over anhydrous sodium sulfate
10. 10
    Filtrationfiltered
11. 11
    Concentrationthe filtrate is concentrated in vacuo
12. 12
    OtherThe residue is further purified by column chromatography on silica gel
13. 13
    Washeluting with hexane

Procedure

Hydrobromic acid (48% wt. in water, 240 ml) is added dropwise to a suspension of 4-ethyl-3-nitroaniline (20 g, 0.12 mol) in water (80 ml), and the mixture is stirred until the solid dissolves. The mixture is cooled to −5° C. and a solution of sodium nitrite (19.8 g, 0.28 mol) in water (100 ml) is added dropwise, maintaining the temperature at 0-5° C. Once the addition is complete, the cooling bath is removed and the reaction mixture is stirred for one hour at room temperature. The mixture is added dropwise to a pre-cooled solution of cuprous bromide (22.4 g, 0.16 mol) in hydrobromic acid (48% wt. in water) at 0° C. The reaction mixture is stirred and allowed to warm to room temperature over three hours. The mixture is extracted with diethyl ether, and the organic extracts are combined, dried over anhydrous sodium sulfate, filtered and the filtrate is concentrated in vacuo. The residue is further purified by column chromatography on silica gel, eluting with hexane to give 4-bromo-1-ethyl-2-nitrobenzene (18 g)

Source