Reaction #487560

Reaction equation

potassium iodide

sulfuric acid

5-bromo-2-ethylaniline

sodium nitrite

→

4-bromo-1-ethyl-2-iodobenzene

Solvents

water

water

water

Conditions

Workup

1. 1
   Temperatureby brief heating
2. 2
   Temperatureat reflux until dissolution
3. 3
   Otherproducing a fine precipitate
4. 4
   Temperaturefurther cooled to approximately 0° C. in an ice/salt bath
5. 5
   Temperaturemaintaining a temperature below 5° C.
6. 6
   FiltrationThe reaction mixture is next filtered
7. 7
   workup.ADDITIONAfter the addition
8. 8
   Temperatureis briefly heated to 80° C.
9. 9
   Temperatureto cool to room temperature again
10. 10
    ExtractionThe reaction mixture is extracted with ethyl acetate (3×50 ml)
11. 11
    Washthe organic phase is washed with 1M aqueous hydrochloric acid (30 ml) and aqueous sodium thiosulfate (2×30 ml)
12. 12
    DryingAfter drying over anhydrous magnesium sulfate and concentration in vacuo 4-bromo-1-ethyl-2-iodobenzene (4.90 g)
13. 13
    Otheris furnished as an orange liquid

Procedure

To a stirred mixture of 5-bromo-2-ethylaniline (3.39 g, 200 mmol) in distilled water (110 ml) is added concentrated sulfuric acid (5.60 ml), followed by brief heating at reflux until dissolution. The mixture is allowed to cool to room temperature, producing a fine precipitate, then further cooled to approximately 0° C. in an ice/salt bath. To this slurry is added an aqueous solution of sodium nitrite (1.17 g, 16.94 mmol) in distilled water (10 ml) dropwise over 15 minutes, maintaining a temperature below 5° C., followed by additional stirring for 30 minutes. The reaction mixture is next filtered then added to a second solution of aqueous potassium iodide (8.44 g, 50.83 mmol) in distilled water (45 ml) dropwise at room temperature. After the addition is complete the solution is briefly heated to 80° C. then allowed to cool to room temperature again. The reaction mixture is extracted with ethyl acetate (3×50 ml), and the organic phase is washed with 1M aqueous hydrochloric acid (30 ml) and aqueous sodium thiosulfate (2×30 ml). After drying over anhydrous magnesium sulfate and concentration in vacuo 4-bromo-1-ethyl-2-iodobenzene (4.90 g) is furnished as an orange liquid.

Source