Acetic Anhydride → 2-Acetamidopyridine-5-boronic acid pinacol ester

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Reaction Steps

5-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-amine (0.3 g, 1.36 mmol) was dissolved in dichloromethane (5 mL) and 4-dimethylaminopyridine 17 mg, 0.136 mmol) was added, followed by triethylamine (0.38 mL, 2.73 mmol) then acetic anhydride (0.153, 1.5 mmol). The mixture was stirred at room temperature for 3.5 h then diluted with dichloromethane and washed with NH4Cl (sat aq) then brine. The organic layer was dried (MgSO4), filtered and concentrated. Chromatography eluting with ethyl acetate gave the desired product (187 mg, 52% yield). 1H-NMR (300 MHz, CDCl3) δ 9.3 (s, 1H), 8.6 (s, 1H), 8.2 (d, 1H), 8.05 (d, 1H), 2.2 (s, 3H), 1.2 (s, 12H).

Provenance & Evidence