The general procedure for the synthesis of 5-chloro-1H-imidazo[4,5-B]pyridin-2(3H)-one from 6-chloro-2,3-diaminopyridine and triphosgene was as follows: 0.143 g (1 mmol) of 6-chloro-pyridine-2,6-diamine was dissolved in 2 ml of methylene chloride, 0.4 g of sodium hydroxide dissolved in 2 ml of water was added to the solution, followed by 0.22 g of triphosgene dissolved in a a solution of 2 ml of dichloromethane. The reaction mixture was treated according to similar literature methods. Colorless crystal product was obtained by ethanol recrystallization. The yield was 0.08 g (0.47 mmol) in 47% yield with a melting point of 374°C. Infrared spectra (IR, cm-1): 3094, 3002, 2817, 1770. 1H NMR (200 MHz, DMSO-d6) δ (ppm): 11.58 (s, 1H, NH), 11.03 (s, 1H, NH), 7.27 (d, 1H, J=8.0 Hz, aromatic H), 7.01 (d, 1H, J= 8.1 Hz, aromatic H).13C NMR (50 MHz, DMSO-d6) δ (ppm): 154.20, 144.34, 139.82, 122.81, 117.08, 115.63.
![5-CHLORO-1,3-DIHYDRO-2H-IMIDAZO[4,5-B]PYRIDIN-2-ONE](/CAS/GIF/40851-98-7.gif)