1420998-43-1

717843-51-1

73183-34-3

1420998-43-1

Synthesis of intermediate Vd: Under argon protection, 3-bromo-2-methoxy-4-methylpyridine Vc (813 mg, 4.02 mmol), bis(pinacolato)diboron (1.12 g, 4.41 mmol), PdCl2(dppf)-DCM (146 mg, 0.20 mmol) and KOAc (1.18 g, 12.0 mmol) were were added to a dry sealed tube followed by dry DMF (10 mL). The reaction mixture was stirred at 100 °C for 1.5 h. After cooling to room temperature, another portion of catalyst (75 mg, 0.092 mmol) was added. The reaction tube was resealed and stirring was continued at 100 °C overnight. After completion of the reaction, the mixture was cooled to room temperature and the solvent was removed by evaporation. The residue was dissolved in dichloromethane (DCM) and washed with water. The organic layer was separated, dried with anhydrous MgSO4, filtered and concentrated. Purification by silica gel column chromatography (eluent: cyclohexane/EtOAc, 10% to 20% gradient) afforded the intermediate Vd as a yellow oil (2.14 g, 51% yield).1H NMR (300 MHz, CDCl3) δ 8.00 (d, J = 5.3 Hz, 1H), 6.65 (d, J = 5.3 Hz, 1H), 3.89 (s 3H), 2.33 (s, 3H), 1.40 (s, 12H).