反应详情

温度

80 °C

2,6-Dichloroisonicotinic acid (2.00 g, 10.42 mmol) was placed in a pressure tube and a solution of dimethylamine in tetrahydrofuran (26 mL, 2 M, 52 mmol) added. The vessel was sealed and heated for 22 h at 80° C. The mixture was cooled to room temperature, transferred to a round-bottom flask and concentrated to dryness. The resulting white semi-solid was taken up in 30 mL of 0.1 N sodium hydroxide solution. 1 N HCl was added dropwise with stirring to adjust the pH of the solution to ca. 3.5, at which point a pale yellow solid formed. This was collected by filtration and dried under vacuum at 45° C. overnight to provide 2-chloro-6-(dimethylamino)isonicotinic acid inner salt (916 mg, 44%). Further acidification of the aqueous solution to pH 1 resulted in the formation of a bright yellow solid, which was also collected and dried under vacuum to give 2-chloro-6-(dimethylamino) isonicotinic acid hydrochloride (1.15 g, 46%). m/z: 201+ [M+H]; 199− [M−H]. For the HCl salt: 1H NMR (400 MHz, DMSO-d6) δ ppm 13.64 (br. s., 1H), 6.96 (d, J=1.0 Hz, 1H), 6.89 (d, J=0.8 Hz, 1H), 3.06 (s, 6H), 2.53 (t, J=5.1 Hz, 1H).

1. customThe vessel was sealed
2. temperatureThe mixture was cooled to room temperature
3. customtransferred to a round-bottom flask
4. concentrationconcentrated to dryness
5. addition1 N HCl was added dropwise
6. customat which point a pale yellow solid formed
7. filtrationThis was collected by filtration
8. customdried under vacuum at 45° C. overnight