Carbon Dioxide → 2,3-Dichloropyridine-4-carboxylic acid

Temperature

-78 °C

To a solution of diisopropylamine (7.0 mL, 50 mmol) in anhydrous THF (100 mL) at −25° C. was added a 1.6M solution of nBuLi in hexanes (31 mL, 50 mmol) dropwise under an inert atmosphere. The reaction mixture was then cooled to −78° C. and 2,3-dichloropyridine was added. The reaction mixture was stirred at −78° C. for 3 hours, then poured onto solid carbon dioxide and aged for 18 hours at room temperature. The mixture was diluted with water (100 mL) and washed with diethyl ether (3×40 mL) then cooled to 0° C., acidified with concentrated HCl (ca. 5 mL) and extracted with diethyl ether (3×50 mL). The combined organic extracts were dried (Na2SO4), filtered and concentrated to give the title compound as a white solid (7.7 g, 80%). 1H NMR (d6-DMSO, 400MHz) 8.49 (d, J=5.0 Hz, 1H), 7.72 (d, J=5.0 Hz, 1H).

1. washwashed with diethyl ether (3×40 mL)
2. temperaturethen cooled to 0° C.
3. extractionextracted with diethyl ether (3×50 mL)
4. dry with materialThe combined organic extracts were dried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated

ORD record

ord-1848f9f0c3bc4bd781fb6ae93e25676e

Source dataset

uspto-grants-2012_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08293763B2