34552-15-3

99268-30-1

34552-15-3

Example 11 Preparation of 2-chloro-3-fluoro-5-methylpyridine: 1.92 g of 2-fluoro-4-chloro-4-formylpentanenitrile (CAS: 99268-30-1) was placed in a 50 mL Carius tube and 10 mL of acetonitrile was added as a solvent. Dry HCl gas was passed into the reaction system for 10 seconds. Subsequently, the reaction mixture was heated at 180°C for 20 min. After completion of the reaction, the acetonitrile solvent was evaporated under reduced pressure. The residue was dissolved in 5 mL of dichloromethane and purified by silica gel column chromatography (230-400 mesh, 4 cm × 20 cm). The first fraction containing the target product 2-chloro-3-fluoro-5-methylpyridine was collected. The solvent was removed under vacuum to give 700 mg of product in 44% yield. The product was characterized by the following data: 1H NMR (acetone-d6) δ 2.35 (s, 3H, -CH3), 7.50 (dd, 1H, pyr-H4), 8.07 (wide s, 1H, pyr-H6); IR (NaCl, neat) 1450 cm-1, 1408 cm-1, 1215 cm-1, 1085 cm-1, 880 cm -1, 720 cm-1, 711 cm-1; CIMS (CM4) MH+ m/e 146 (100%), MH++2 m/e 148 (35%).