The general procedure for the synthesis of 2-chloro-6-hydroxynicotinic acid from 2,6-dichloronicotinic acid is as follows:
1. 2,6-dichloronicotinic acid (25 g, 130 mmol) and NaOH solution (325 mL, 2N) were added to a 500 mL round bottom flask.
2. The reaction mixture was refluxed at 129°C for 4 hours.
3. Upon completion of the reaction, the mixture was cooled to 0°C.
4. The reaction mixture was acidified to room temperature with 6N aqueous HCl solution.
5. The resulting precipitate was collected by filtration.
6. The precipitate was dried under reduced pressure to give 2-chloro-6-hydroxynicotinic acid (19.87 g, 88% yield).
