2-(Methylthio)oxazolo[4,5-b]pyridine

Synthesis

Step 2: Preparation of 2-(methylthio)oxazolo[4,5-b]pyridine To a stirred solution of oxazolo[4,5-b]pyridine-2(3H)-thione (3.0 g, 19.73 mmol) in ethyl acetate (30 mL) at room temperature was sequentially added potassium carbonate (3.81 g, 27.62 mmol) and iodomethane (3.08 g, 21.71 mmol). The reaction mixture was stirred overnight at room temperature. After completion of the reaction, the mixture was diluted with water (100 mL) and extracted with ethyl acetate (2 x 50 mL). The organic phases were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 2-methylthiooxazolo[4,5-b]pyridine (3.0 g, 93.75% yield). 1H NMR (CDCl3, 300 MHz): δ 8.46-8.44 (d, 1H), 7.71-7.68 (d, 1H), 7.20-7.15 (m, 1H), 2.81 (s, 3H). LCMS: m/z 167.0 [M + H]+.

References

[1] Patent: WO2015/104688, 2015, A1. Location in patent: Page/Page column 36
[2] Patent: US2016/340366, 2016, A1. Location in patent: Paragraph 0207; 0208
[3] Journal of Organic Chemistry, 1995, vol. 60, # 17, p. 5721 - 5725
[4] Ultrasonics Sonochemistry, 2010, vol. 17, # 5, p. 783 - 788
[5] Bioorganic and Medicinal Chemistry Letters, 2012, vol. 22, # 5, p. 2075 - 2078