反应详情

温度

90 °C

To a solution of 5-chloro-3-methylpicolinonitrile (24.0 g, 157 mmol) in EtOH (100 mL) was added NaOH 5.0N (110 ml, 550 mmol). The resulting mixture was refluxed at 90° C. for 18 h. After cooling to RT, the reaction mixture was concentrated, diluted with water and the pH of the solution was adjusted to 4 by addition of 5N HCl. The solid that precipitated was filtered and set aside. The filtrate was extracted with EtOAc (2×). The aqueous layer was again acidified with 5N HCl to pH 4 and extracted with EtOAc (2×). The EtOAc extracts were combined, dried, and concentrated. The solid obtained from all the workup steps were combined and dried in a high vac oven at 40° C. for 12 h to give the title compound 5-chloro-3-methylpicolinic acid (24.1 g, 140 mmol, 89% yield). LC/MS (ESI+) m/z=172.0 (M+H)+; 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 11.29 (br. s., 1H), 8.41 (d, J=1.76 Hz, 1H), 7.73 (d, J=1.76 Hz, 1H), 2.75 (s, 3H).

1. temperatureAfter cooling to RT
2. concentrationthe reaction mixture was concentrated
3. additiondiluted with water
4. additionthe pH of the solution was adjusted to 4 by addition of 5N HCl
5. customThe solid that precipitated
6. filtrationwas filtered
7. extractionThe filtrate was extracted with EtOAc (2×)
8. extractionextracted with EtOAc (2×)
9. customdried
10. concentrationconcentrated
11. customThe solid obtained from all the workup steps
12. customdried in a high vac oven at 40° C. for 12 h