Synthesis
General procedure for the synthesis of 6-methyl-3-pyridineboronic acid from 6-methyl-3-pyridinol trifluoromethanesulfonate and bis(pinacolato)diboronate: 6-methyl-3-pyridinol trifluoromethanesulfonate (4.6 mmol) was dissolved in acetonitrile (30 mL) and transferred to a 5 mL microwave reaction tube. To this solution was added 1.5 equivalents of bis(pinacolato)diboron (6.9 mmol; 1.71 g). The mixture was stirred on a magnetic stirrer until complete dissolution. Subsequently, potassium acetate (13.8 mmol; 1.35 g) and [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride (98 mg, 0.03 mol%) were added to the mixture. The reaction mixture was placed in a microwave reactor and heated at 160°C for 2 x 600 seconds. Upon completion of the reaction (monitored by LC-MS), the acetonitrile was removed by evaporation to give a black solid. The solid was dissolved in DMSO and purified by HPLC to give the final target product 6-methyl-3-pyridineboronic acid (580 mg, 92% yield; 4.2 mmol). Mass spectral data: MH+ = 138.
