Hydrochloric Acid → 3-Chloro-5-methoxypicolinic acid

Temperature

50 °C

In a 2-L round bottom flask, the methyl 3-chloro-5-methoxypicolinate (19.1 g, 95 mmol) was suspended in MeOH (104 ml). Aqueous 1N sodium hydroxide (104 ml, 104 mmol) was added. An air-cooled condenser was attached, and the reaction flask was heated in a 50° C. oil bath. After 1.5 h, the reaction was concentrated to remove the MeOH until a yellow sludge remained. The sludge was dissolved in 110 ml of water. The aqueous phase was extracted with diethyl ether (50 ml), which was discarded. The aqueous phase was acidified with aqueous hydrogen chloride (23 ml, 114 mmol), which caused extensive precipitation. The sludgy aqueous mixture was extracted with DCM in 6×250 ml. The organic layer were dried over MgSO4 and concentrated to yield 3-chloro-5-methoxypicolinic acid (17.88 g, 95 mmol, 100%) as a yellow solid. MS m/z=188 (M+H).

1. customAn air-cooled condenser was attached
2. concentrationthe reaction was concentrated
3. customto remove the MeOH until a yellow sludge
4. dissolutionThe sludge was dissolved in 110 ml of water
5. extractionThe aqueous phase was extracted with diethyl ether (50 ml), which
6. customprecipitation
7. extractionThe sludgy aqueous mixture was extracted with DCM in 6×250 ml
8. dry with materialThe organic layer were dried over MgSO4
9. concentrationconcentrated

ORD record

ord-15518de7707c465f9810e7cbc6b60797

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09309263B2