Ethyl 4-bromo-1-methyl-1H-pyrrole-2-carboxylate (5.00 g, 21.6 mmol) prepared in the Step 10-1-2 was dissolved in N,N-dimethylformamide (20 ml)/water (5 ml), and sodium carbonate (6.87 g, 64.8 mmol), tetrakis(triphenylphosphine)palladium (120 mg, 0.1 mmol) and 4-chloro-2-methoxyphenylboronic acid (8.04 g, 4.32 mmol) was added to the solution. The mixture was heated under reflux for 5 hours. After the mixture was allowed to cool, water and chloroform was added to the mixture. The organic phase was collected by separation and dried over anhydrous magnesium sulfate. The solvent was distilled off, and the resulting residue was purified by silica gel column chromatography (ethyl acetate:n-hexane=1:3) to give the title compound (3.23 g, 51%).
