53052-06-5

16867-03-1

140-89-6

53052-06-5

Step 1: Synthesis of oxazolo[4,5-b]pyridine-2(3H)thione 2-Amino-3-hydroxypyridine (5.0 g, 45.45 mmol) and potassium ethylxanthate (8.0 g, 49.99 mmol) were dissolved in pyridine (50 mL), and the reaction was stirred at 110 °C overnight. Upon completion of the reaction, the mixture was cooled to 0 °C, ice water was added and acidified with concentrated hydrochloric acid. The precipitated solid was collected by filtration and dried under vacuum to afford the target product oxazolo[4,5-b]pyridine-2(3H)thione (6.0 g, 86.95% yield). Product characterization data: 1H NMR (DMSO-d6, 300 MHz): δ 8.24-8.22 (d, 1H), 7.90-7.87 (d, 1H), 7.30-7.26 (m, 1H). LCMS: m/z 153.0 [M + H]+.