Under ice bath conditions, 60% sodium hydride (82 mg, 2.05 mmol) was slowly added to dimethyl sulfoxide (2.5 mL) and stirred for 5 min at room temperature. Subsequently, N-(3-cyano-7-ethoxy-4-hydroxyquinolin-6-yl)acetamide (0.5 g, 1.37 mmol) was added in batches and stirring was continued for 2 h at room temperature. After confirming the complete consumption of raw materials by thin layer chromatography (TLC) monitoring, the reaction mixture was slowly poured into water (10 mL) and the pH was adjusted to 3-4 with 4 M hydrochloric acid solution.The precipitated light yellow solid was collected by filtration and dried to give N-(3-cyano-7-ethoxy-4-hydroxyquinolin-6-yl)acetamide (0.35 g, 94.3% yield).