Hydrochloric Acid → 3-Pyridinecarboxylic acid, 2-(2,4-dichlorophenoxy)-

Participants

Reaction Steps

To a solution of 2-chloro-nicotinic acid (2.15 g, 13.65 mmol, 1.0 equiv; [CAS RN 2942-59-8]) and 2,4-dichloro-phenol (2.22 g, 13.65 mmol, 1.0 equiv; [CAS RN 120-83-2]) in toluene (40 mL) was added caesium carbonate (8.89 g, 27.29 mmol, 2.0 equiv; [CAS RN 534-17-8]) and tetrakis(acetonitrile)copper(I) hexafluorophosphate (1.02 g, 2.73 mmol, 0.2 equiv; [CAS RN 64443-05-6]). The reaction mixture was heated to reflux over night. The solvent was evaporated under reduced pressure and the crude reaction product taken up in water (100 mL) acidified to pH 1 by addition of a solution of 1 M HCl and extracted with ethyl acetate (3×100 mL). The combined organic phases were dried over MgSO4 and the product purified by silica column chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting with a gradient of dichloromethane/methanol affording 1.69 g (44%) of the title compound as an off-white solid. 1H NMR (400 MHz, DMSO): δ7.26 (dd, J=7.6 Hz, J=4.8 Hz, 1H), 7.36 (d, J=8.7 Hz, 1H), 7.49 (dd, J=8.7 Hz, J=2.6 Hz, 1H), 7.76 (d, J=2.4 Hz, 1H), 8.25 (dd, J=4.8 Hz, J=2.2 Hz, 1H), 8.30 (dd, J=7.5 Hz, J=2.2 Hz, 1H), 13.33 (s, 1H). MS (ISN): 282.3 [M−H]−.

Provenance & Evidence