Hexafluorophosphoric acid → 2-Bromo-5-(4-chloro-phenyl)-3-fluoro-pyridine

Temperature

0 °C

243 mg (3.53 mmol) sodium nitrite in 0.5 mL water are added dropwise at −5° C. to a solution of 1.00 g (3.53 mmol) 2-bromo-5-(4-chloro-phenyl)-pyridin-3-ylamine in 2 mL water and 2.04 mL concentrated HCl. Then at 0° C. 1.56 mL (10.6 mmol) 60% hexafluorophosphoric acid in water are added and the reaction is stirred for a further hour at 0° C. The diazonium salt is suction filtered, washed with cold water, isopropanol and ether and dried overnight in the desiccator at RT and 7 mbar. This is then added batchwise at 90° C. to 50 mL PE (boiling point 100-140° C.). After the reaction solution has cooled the mixture is made alkaline with saturated Na2CO3 solution. The aqueous phase is extracted with EtOAc and the organic phase is washed successively with saturated Na2CO3 solution and water. The organic phase is dried over MgSO4 and the solvent is eliminated i.vac. The purification is carried out by column chromatography on silica gel (PE).

1. customat 0° C
2. filtrationfiltered
3. washwashed with cold water, isopropanol and ether
4. customdried overnight in the desiccator at RT
5. additionThis is then added batchwise at 90° C. to 50 mL PE (boiling point 100-140° C.)
6. temperatureAfter the reaction solution has cooled the mixture
7. extractionThe aqueous phase is extracted with EtOAc
8. washthe organic phase is washed successively with saturated Na2CO3 solution and water
9. dry with materialThe organic phase is dried over MgSO4
10. customThe purification

ORD record

ord-c10b7e04dd6d4e9397bc7e389a310201

Source dataset

uspto-grants-2008_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07452911B2