Reaction #76184

Reaction equation

hydrobromic acid

3-cyano-2,4-dichloro-5-fluoroaniline

hydrochloric acid water

sodium nitrite

water

→

3-cyano-2,4-dichloro-5-fluorobromobenzene

Yield 86.2%

Conditions

Workup

1. 1
   workup.STIRRINGThe reaction mixture was stirred for 2 hours
2. 2
   workup.WAITallowed overnight
3. 3
   workup.DISTILLATIONThe resulting mixture was wet-distilled
4. 4
   ExtractionThe distilled fraction was extracted with toluence
5. 5
   WashThe oil layer was washed successively with 10% aqueous solution of NaOH, concentrated sulfuric acid and water
6. 6
   Dryingdried over anhydrous sodium sulfate
7. 7
   OtherAfter removing the solvent
8. 8
   Otherthe residue was crystallized from toluene

Procedure

47.2 g of 3-cyano-2,4-dichloro-5-fluoroaniline (0.23 mol) were added to a solution of 150 ml of hydrochloric acid-water (1:1). The resulting mixture was stirred to be a slurry and then cooled to 0-5° C. A solution of sodium nitrite (16.7 g, 0.242 mol) and water (46 ml) was added thereto over 30 minutes. The resulting solution was added to a solution of cuprous bromide (0.275 mol) in 147 ml of hydrobromic acid. The reaction mixture was stirred for 2 hours and allowed overnight. The resulting mixture was wet-distilled. The distilled fraction was extracted with toluence. The oil layer was washed successively with 10% aqueous solution of NaOH, concentrated sulfuric acid and water, and dried over anhydrous sodium sulfate. After removing the solvent, the residue was crystallized from toluene to give 53.3 g of 3-cyano-2,4-dichloro-5-fluorobromobenzene (0.198 mol) in 86.2% yield.

Source