2-Isopropoxy-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine

Uses

2-Isopropoxypyridine-5-boronic acid, pinacol ester

Synthesis

Under nitrogen protection, to a stirred 1,4-dioxane (50 ml) of 5-bromo-2-isopropoxypyridine (5 g, 23.14 mmol), potassium acetate (5.68 g, 57.9 mmol), and 4,4,4,4,5,5,5,5-octamethyl-2,2'-bis(1,3,2-dioxaborolane) (8.81 g, 34.7 mmol) PdCl2(dppf)-DCM adduct (1.89 g, 2.314 mmol) was added to the suspension. The reaction mixture was heated at 110°C for 1 hour. After completion of the reaction, water was added to the mixture and extracted with ethyl acetate. The organic layers were combined, washed sequentially with water and brine, dried with Na2SO4 and concentrated under reduced pressure. The crude product was purified by column chromatography to afford 6-isopropoxypyridine-3-boronic acid pinacol ester as an oil (5 g, 82% yield).1H NMR (400 MHz, chloroform-d) δ 8.54 (s, 1H), 7.92 (d, J = 8.3Hz, 1H), 6.76-6.46 (m, 1H), 5.45-5.25 (m, 1H), and 1.37 (d, J = 2.4Hz, 6H), 1.28 (s, 12H).

References

[1] Patent: WO2017/37682, 2017, A1. Location in patent: Page/Page column 71; 72
[2] Patent: WO2005/123675, 2005, A1. Location in patent: Page/Page column 55
[3] Patent: WO2016/161160, 2016, A1. Location in patent: Paragraph 0160
[4] ACS Medicinal Chemistry Letters, 2018, vol. 9, # 7, p. 761 - 767
[5] Patent: WO2009/105500, 2009, A1. Location in patent: Page/Page column 219-220