Step 1. Synthesis of 2-chloro-5-methylpyrimidine
To a stirred solution of 2,4-dichloro-5-methylpyrimidine (4.00 g, 24.5 mmol) dissolved in a solvent mixture of benzene (16.0 mL) and water (40.0 mL) was added zinc powder (4.81 g, 73.6 mmol) and ammonia (8.80 mL, 24.5 mmol) sequentially at room temperature. The reaction mixture was heated and refluxed for 18 hours, then cooled to room temperature and filtered through a diatomaceous earth pad. The filtrate was extracted with ether (Et2O), and the combined organic phases were washed with saturated brine, dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: hexane/ethyl acetate = 1:1) to afford the target compound 2-chloro-5-methylpyrimidine (2.44 g, 77% yield) as a yellow oil.1H NMR (400 MHz, CDCl3) δ 2.33 (3H, s), 8.47 (2H, s).
