To a mixture of 5-(ethoxycarbonyl)-4′-methylbiphenyl-3-carboxylic acid (1.5 g, 5.3 mmol), N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (2.0 g, 10 mmol), 1-hydroxybenzotriazole hydrate (0.32 g, 2.1 mmol), and CH2Cl2 (50 mL) were added (6-methylpyridin-3-yl)methanamine (0.97 g, 7.9 mmol) and N,N-diisopropylethylamine (1.8 mL, 10 mmol). The mixture was stirred at room temperature for 4 h, and then washed with water and aq. Na2CO3 solution, dried (Na2SO4), and concentrated in vacuo. The residue was purified by silica gel column to afford a white foam.
