617678-32-7

64-18-6

617678-31-6

617678-32-7

The general procedure for the synthesis of 5-(trifluoromethyl)-1H-imidazo[4,5-b]pyridine from formic acid and N-benzyl-N-(3-nitro-6-trifluoromethylpyridin-2-yl)amine (CAS:617678-31-6) was as follows: N-benzyl-N-(3-nitro-6-trifluoromethylpyridin-2-yl)amine (110 mg, 0.37 mmol) was was dissolved in formic acid (25 mL) and 10% Pd/C (25 mg) aqueous slurry was added. The reaction mixture was heated to reflux for 24 hours. After completion of the reaction, it was cooled to room temperature, filtered through diatomaceous earth and the filtrate was concentrated by rotary evaporation. Subsequently, it was azeotroped with toluene (2 x 10 mL) to remove residual water to give a white solid. The solid was dispersed between ethyl acetate and saturated aqueous sodium bicarbonate solution for partitioning. The organic phase was concentrated by evaporation and the residue was purified by fast column chromatography (eluent: ethyl acetate-10% methanol/ethyl acetate gradient) to afford the target product, 5-(trifluoromethyl)-1H-imidazo[4,5-b]pyridine, as a white solid (45 mg, 65% yield). The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 7.73 (1H, d, J=8 Hz), 8.33 (1H, d, J=8 Hz), 8.42 (1H, s), 12.25 (1H, br s); Mass Spectrometry (m/z): 188 ([M+H]+).