Example 15A Synthesis of 2-amino-6-chloropyridine-3-carbonitrile: First, 11.15 g (53.6 mmol) of 2-amino-6-chloropyridine-3-carboxaldehyde oxime hydrochloride (Example 14A) was suspended in dioxane, followed by the addition of 13 ml (161 mmol) of pyridine. After cooling the mixture to 0°C, 8.3 ml (58.95 mmol) of trifluoroacetic anhydride was slowly added dropwise. After the dropwise addition, the reaction mixture was gradually warmed to room temperature and stirred continuously at 60°C for 2 hours. After completion of the reaction, the mixture was dissolved in a mixed system of ethyl acetate and aqueous sodium bicarbonate. The organic phase was separated, washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate and subsequently concentrated on a rotary evaporator. The concentrated residue was suspended in a solvent mixture of dichloromethane and ether (3:1 v/v) and the solid product was collected by filtration and dried to give 5.56 g (66% yield) of the target compound as a solid. The product was analyzed by LCMS (Method 6): retention time Rt = 1.0 min, m/z = 154 (M + H)+. 1H-NMR (400 MHz, DMSO-d6) data: δ= 7.91 (d, 1H), 7.38 (s, 2H), 6.69 (d, 1H).
