Palladium catalyst (10% loaded on charcoal, 330 mg) was added to a solution of 2-chloro-6-trifluoromethoxyisonicotinic acid (43, 1.1 g, 4.55 mmol) and ammonium formate (574 mg, 9.1 mmol, 2 eq.) in methanol (8 mL) at 25 °C and mixed by stirring. The reaction mixture was stirred continuously at 55 °C for 16 hours. After completion of the reaction, filtration was carried out and the filtrate was concentrated by evaporation. The residue was partitioned between ethyl acetate (2 x 15 mL) and 2.0 M hydrochloric acid (20 mL) for extraction. The organic layers were combined, dried over sodium sulfate and evaporated to give the pure product 2-trifluoromethoxyisonicotinic acid (44,760 mg, 3.7 mmol, 81% yield) as a white powder with a melting point of 149-152°C. 1H NMR (CD3OD, 300 MHz): δ=8.39 (d, J=5.1 Hz, 1H), 7.77 (dd, J=5.1,1.0 Hz, 1H), 7.51 (d, J=1.0 Hz, 1H).19F NMR ((CD3)2CO, 282 MHz): δ=-57.6.13C NMR (CD3OD, 75 MHz): δ=164.9,157.2,148.4,143.3,121.8,120.3 (q, J=260 Hz). 112.5. Elemental analysis (C7H4F3NO3, Mr=207): calculated values C 40.59%, H 1.95%, N 6.76%; measured values C 40.28%, H 2.21%, N 6.67%.
