Tert-butyl 4-((5-bromo-3-(((4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl) carbamoyl)-2-methylphenyl)(methyl)amino)piperidin-1-carboxylate (0.5 g, 0.892 mmol), (6-formylpyridin-3-yl))boronic acid (0.31 g, 1.33 mmol) and Pd(PPh3)4 (0.103 g, 0.082 mmol) in 1,4-dioxane (10 mL) was purged with argon for 10 min. Then, 2 M Na2CO3 solution (0.34 g, 3.21 mmol) was added to it and again argon was purged through it for 10 min. The reaction mixture was stirred at 100° C. for 2 h. After completion of the reaction, water was added to it and extraction was carried out using 5% MeOH in DCM. The combined organic layers were washed with water, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure to afford crude material which was purified by column chromatography over silica gel (60-120 mesh size) to afford tert-butyl 4-((3-(((4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl)carbamoyl)-5-(6-formylpyridin-3-yl)-2-methylphenyl)(methyl)amino)piperidine-1-carboxylate (0.40 g, 87.9%).
