2-Ethoxy-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-pyridine

57883-25-7

73183-34-3

848243-23-2

A suspension was prepared in DMSO (100 mL) with 3-bromo-2-ethoxypyridine (28.69 g, 142.0 mmol), bis(pinacolato)diboron (43.3 g, 170.5 mmol) and potassium acetate (41.8 g, 425.9 mmol). The suspension was degassed with nitrogen and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (5.8 g, 7.93 mmol) was added. The reaction mixture was stirred at 95 °C for 6 hours. After completion of the reaction, the reaction mixture was filtered through an Arbocel pad and washed with ethyl acetate (500 mL). The filtrate was concentrated under vacuum and the crude product was purified by silica gel column chromatography using a 50% cyclohexane solution of ethyl acetate as eluent to afford 2-ethoxypyridine-3-boronic acid pinacol ester as a red oil (34.4 g, 74% yield).1H NMR (400 MHz, CDCl3) data were as follows: δ 1.35 (s, 12H), 1.39 (m, 3H). 4.37 (m, 2H), 6.81 (m, 1H), 7.89 (m, 1H), 8.19 (m, 1H).Results of LCMS analysis: retention time (Rt) = 3.27 min, mass spectrum (MS) m/z 250 [MH]+.