Bromine → 1,5-Dibromo-2,4-difluorobenzene

2,4-difluorobromobenzene (3 g, 15.5 mmol) and 260 mg of iron filings were placed in a two-neck flask, and 15 ml of dichloromethane was then added thereto. The two-neck flask was cooled in an ice bath, and a solution including bromine (1 ml, 18.7 mmol) and 15 ml of dichloromethane was added dropwise to the two-neck flask using an isobaric funnel. Next, the contents in the two-neck flask were heated under reflux for 3 hours. During heating, brown gas was produced. Then, the temperature was reduced to 20° C., and 50 ml of a sodium metabisulfite (Na2S2O5) aqueous solution (10%) was mixed with the contents in the two-neck flask by stirring for 1 hour for terminating the reaction therein. Thereafter, the contents in the two-neck flask were washed several times with deionized water to collect an organic layer, the organic layer was dehydrated using sodium sulfate (Na2SO4), and the solvent in the organic layer was removed, followed by column chromatography (SiO2, n-hexane), thereby obtaining white crystals (3.5 g, 83% yield).

1. temperatureThe two-neck flask was cooled in an ice bath
2. additionwas added dropwise to the two-neck flask
3. temperatureNext, the contents in the two-neck flask were heated
4. temperatureunder reflux for 3 hours
5. temperatureDuring heating
6. custombrown gas was produced
7. customwas reduced to 20° C.
8. customfor terminating
9. customthe reaction
10. washThereafter, the contents in the two-neck flask were washed several times with deionized water
11. customto collect an organic layer
12. customthe solvent in the organic layer was removed

ORD record

ord-79e8b74de6464014a5f1747f9ef8470c

Source dataset

uspto-grants-2015_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09219237B1