General procedure for the synthesis of 2-(dimethylamino)pyridine-5-boronic acid from 5-bromo-N,N-dimethylpyridin-2-amine and pinacol ester of bis(boronic acid): to a solution of 1,4-dioxane (20 mL) in 5-bromo-N,N-dimethylpyridin-2-amine (400 mg, 1.989 mmol), was added sequentially 4,4,4',4',5,5,5',5'-octa methyl-2,2'-bis(1,3,2-dioxaborolane) (606 mg, 2.387 mmol), PdCl2(dppf)-CH2Cl2 adduct (162 mg, 0.199 mmol) and potassium acetate (390 mg, 3.98 mmol). The reaction mixture was heated to 100 °C and stirred overnight under nitrogen protection. After completion of the reaction, the mixture was filtered and the filtrate was concentrated under vacuum to afford the crude product (6-(dimethylamino)pyridin-3-yl)boronic acid (420 mg, 0.496 mmol, 25% yield) as a brown oil.LCMS analysis showed the [M+H]+ peak at 167.1.
