Sodium Hydroxide → 5-Chloro-3-fluoropyridine-2-carbonyl chloride

Temperature

90 °C

71.38 g of 3-fluoro-5-chloro-2-pyridinecarboxylic acid (Example P4) are placed in a round-bottomed flask and heated to 90° C. 59 ml of thionyl chloride are added dropwise from a dropping funnel over a period of 30 minutes, and the gas formed is introduced into sodium hydroxide solution. Stirring is then carried out for 5 hours at 100° C., after which the thionyl chloride is distilled off at normal pressure. After the addition of 50 ml of dry toluene, 20 ml thereof are distilled off. The resulting solution is poured into 200 ml of n-hexane and stirred overnight. After cooling in an ice-bath, the mixture is filtered and the filtration residue is washed twice with n-hexane. 68.7 g of the desired compound are obtained in the form of a brown solid.

1. customthe gas formed
2. distillationafter which the thionyl chloride is distilled off at normal pressure
3. additionAfter the addition of 50 ml of dry toluene, 20 ml
4. distillationthereof are distilled off
5. additionThe resulting solution is poured into 200 ml of n-hexane
6. stirringstirred overnight
7. temperatureAfter cooling in an ice-bath
8. filtrationthe mixture is filtered
9. washthe filtration residue is washed twice with n-hexane

ORD record

ord-2d9ff9ad64174f6f89400c17fbb873b6

Source dataset

uspto-grants-2001_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06274536B1