General procedure for the synthesis of 2,3-dichloro-5-hydroxypyridine from 5,6-dichloropyridin-3-yl acetate: an aqueous solution (7 mL) of potassium hydroxide (KOH, 728 mg, 13 mmol) was slowly added to an aqueous solution (7 mL) of tetrahydrofuran (THF, 10 mL) of 5,6-dichloropyridin-3-yl acetate (1 g, 4.8 mmol) at 0 °C. After the addition was completed, the reaction mixture was stirred for 2 h at room temperature. Subsequently, the pH of the mixture was adjusted to a weak base with dilute hydrochloric acid and filtered. The filtrate was purified by recrystallization to afford the target product 2,3-dichloro-5-hydroxypyridine (517 mg, yield: 65%). The structure of the product was confirmed by 1H NMR (400 MHz, DMSO-d6) with chemical shifts δ (ppm) of 7.47 (d, 1H), 7.93 (d, 1H), 10.72 (s, 1H).
