The preparation of 2-CHLORO-7-METHOXY-QUINOLINE-3-CARBALDEHYDE is as follows: N-p-tolylacetamide (2b) (0.05 mol) was dissolved in 9.6 mL of dimethylformamide (0.125 mol), and 32 mL of phosphorus oxychloride (0.35 mol) was gradually added to the solution at 0 °C. The reaction mixture was placed in a round-bottom flask (RBF) equipped with a reflux condenser and a drying tube, and heated in an oil bath at 75-80 °C for 4-16 hours. The solution was then cooled to room temperature and subsequently poured into 100 mL of ice water. The precipitate was collected by filtration and recrystallized from ethyl acetate to give 2-CHLORO-7-METHOXY-QUINOLINE-3-CARBALDEHYDE, yield 75%; MP 122-123℃ (literature 123℃); FT-IR (ATR) ⁻¹ (cm⁻¹): 3051 (aromatic CH), 2873 (aldehyde CH), 1686 (C=O), 1576 (C=N), 1055 (C-Cl); ¹H NMR (400 MHz, chloroform-d): ⁻¹ 0.55 (s, 1H), 8.66 (s, 1H), 7.96 (d, J = 8.5 Hz, 1H), 7.79-7.63 (m, 2H), 2.57 (s, 3H); MS-API: [M+H] + 206.02 (calculated 205.03).
