Sulfuric Acid → 5-Bromo-2-iodo-1,3-dimethylbenzene

Temperature

60 °C

To a stirred mixture of 4-bromo-2,6-dimethylaniline (75 g, 0.37 mol) in distilled water (75 ml) is added concentrated sulphuric acid (75 ml), followed by brief heating to 60° C. for 1 hour until dissolution is complete. The mixture is allowed to cool to room temperature then further cooled to approximately 0° C. in an ice/salt bath. To this slurry is added an aqueous solution of sodium nitrite (25.33 g, 0.36 mol) in distilled water (126 ml) dropwise over 15 minutes, maintaining the temperature below 5° C., followed by additional stirring for 30 minutes. The reaction mixture is allowed to come to room temperature and then a solution of aqueous potassium iodide (187.6 g, 1.13 mol) in distilled water (190 ml) is added 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 (750 ml×3) and the organic phase is washed with 1M aqueous hydrochloric acid (200 ml) and aqueous sodium thiosulfate (2×200 ml). The organic phase is dried over anhydrous sodium sulphate and concentrated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-bromo-2,6-dimethyl-1-iodo benzene (75 g) as an orange liquid.

1. temperatureto cool to room temperature
2. temperaturethen further cooled to approximately 0° C. in an ice/salt bath
3. temperaturemaintaining the temperature below 5° C.
4. customto come to room temperature
5. additionAfter the addition
6. temperatureis briefly heated to 80° C.
7. temperatureto cool to room temperature again
8. extractionThe reaction mixture is extracted with ethyl acetate (750 ml×3)
9. washthe organic phase is washed with 1M aqueous hydrochloric acid (200 ml) and aqueous sodium thiosulfate (2×200 ml)
10. dry with materialThe organic phase is dried over anhydrous sodium sulphate
11. concentrationconcentrated under reduced pressure
12. customThe residue is purified by column chromatography on silica gel

ORD record

ord-0d89030a099e400a84015b8ec7853607

Source dataset

uspto-grants-2014_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08895761B2