Hydrochloric Acid → Ethyl 4-chloro-6-methylpyridine-2-carboxylate

Temperature

90 °C

A mixture of methyl 6-methylpyridine-2-carboxylate N-oxide (2.29 g), a 4N solution of hydrogen chloride in ethyl acetate (5 ml) and ethyl acetate (15 ml) was stirred at room temperature for 30 minutes. The reaction mixture was concentrated and the resultant residue was combined with phosphorus oxychloride (17.90 g), and stirred at 90° C. for 2 hours with heating. The reaction mixture was concentrated, and the resultant residue was diluted with ice-water and then combined with an aqueous solution of potassium carbonate to make the solution basic. The mixture was extracted with dichloromethane, and the organic phase was dried and concentrated. A solution of the residue obtained and triethylamine (5 ml) in ethanol (50) was heated under reflux for 10 hours. The reaction mixture was concentrated, and the residue was combined with water and ethyl acetate, and the organic phase was isolated, dried and concentrated to obtain the title compound (1.74 g) as a tan oil.

1. concentrationThe reaction mixture was concentrated
2. temperaturewith heating
3. concentrationThe reaction mixture was concentrated
4. additionthe resultant residue was diluted with ice-water
5. extractionThe mixture was extracted with dichloromethane
6. customthe organic phase was dried
7. concentrationconcentrated
8. customA solution of the residue obtained
9. temperatureunder reflux for 10 hours
10. concentrationThe reaction mixture was concentrated
11. customthe organic phase was isolated
12. customdried
13. concentrationconcentrated

ORD record

ord-6b1f2e4c9fa44a419456670866678ae7

Source dataset

uspto-grants-2004_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06723722B1