58584-92-2

38496-18-3

58584-92-2

The general procedure for the synthesis of 2-amino-6-chloronicotinic acid (Inter.2) using 2,6-dichloronicotinic acid (Inter.I) as starting material is as follows: 1. 2,6-dichloronicotinic acid (Inter.I) (1 equiv.) was mixed with liquid ammonia to prepare a 0.6 M ammonia solution. 2. The suspension is transferred to a pressure vessel, sealed and slowly heated to 130°C. At this temperature, the system pressure reaches 18 bar. 3. The temperature and pressure conditions were maintained for 16 hours. 4. upon completion of the reaction, cool the mixture to room temperature. 5. carefully open the pressure vessel and pour the reaction mixture into ice-cold water (in the same volume as the volume of reactants). 6. Acidify the solution to pH 1-2 using concentrated hydrochloric acid, at which point a precipitate is formed. 7. Warm the acidic mixture to room temperature and continue stirring for 30 minutes. 8. Extract the suspension with ether (400 ml each time, 3 times). 9. The organic extracts were combined, filtered and the filtrate was concentrated under vacuum to give a white solid. 10. The resulting solid was dried over P2O5 to afford the target compound 2-amino-6-chloronicotinic acid (Inter.2) in 90% yield and 96% purity. The product can be used directly without further purification. Mass spectral data: m/z (LC-MS ESP): 173 [M + H]+, retention time R/T = 3.63 min.