Bromine → 2-Bromo-3-fluoro-5-(trifluoromethyl)pyridine

The 3-fluoro-5-(trifluoromethyl)-picolinic acid (7.35 g, 0.035 mole) starting material was put into 150 ml of dry carbon tetrachloride and then red mercuric oxide (9.1 g, 0.042 mole) was added and the mixture was stirred and refluxed 1 hour and 25 minutes. A solution of bromine (6.7 g, 0.042 mole) in 20 ml of dry carbon tetrachloride was added slowly with the mixture at reflux over the next 21/3 hours. Light from a UV lamp was directed on the reaction mixture during the addition and the reaction mixture was refluxed for another hour. 25 Ml more of dry carbon tetrachloride was added and the refluxing was continued for about 16 hours more while UV radiation was applied. The reaction was then filtered through CELITE diatomaceous earth to remove the mercury salt. The carbon tetrachloride was removed on a still and the product was distilled over to yield 2.45 g of yellow oil with an analysis of, in percent by weight:

1. temperaturerefluxed 1 hour and 25 minutes
2. temperatureat reflux over the next 21/3 hours
3. additionLight from a UV lamp was directed on the reaction mixture during the addition
4. temperaturethe reaction mixture was refluxed for another hour
5. filtrationThe reaction was then filtered through CELITE diatomaceous earth
6. customto remove the mercury salt
7. customThe carbon tetrachloride was removed on a still and the product
8. distillationwas distilled over

ORD record

ord-a73b85c47e9549e5bce85b96223acf17

Source dataset

uspto-grants-1990_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

USRE033478