A mixture of ethyl 2-[2-(acetylamino)-5-methylpyridin-4-yl]-4-iodo-1,3-oxazole-5-carboxylate (0.14 g, 0.33 mmol), (2-chlorophenyl)boronic acid (0.076 g, 0.49 mmol), tetrakis(triphenylphosphine)palladium(0) (0.038 g, 0.032 mmol), and cesium carbonate (0.53 g, 1.62 mmol) in 1,4-dioxane (4.5 mL) and water (0.2 mL) was subjected to microwave irradiation at 150° C. for 20 min. The reaction mixture was filtered and the filtrate was concentrated. To the residue were added MeOH (10 mL) and aqueous NaOH (0.5 M, 1.5 mL). The mixture was allowed to stir at rt for 8 h and then concentrated to give 2-[2-(acetylamino)-5-methylpyridin-4-yl]-4-(2-chlorophenyl)-1,3-oxazole-5-carboxylic acid which was used in next step without further purification.
