Phase 2: Preparation of 2-iodo-6-methoxypyrazine
2,6-Diiodopyrazine (5.0 g, 15 mmol) was added to a pre-prepared methanolic solution of sodium methanolate (prepared by reacting sodium metal (0.35 g, 15 mmol) with methanol (40 mL)). The reaction mixture was heated to reflux temperature and maintained for 1 hour. After completion of the reaction, it was cooled to room temperature and the reaction solution was diluted with water (200 mL) and subsequently extracted with diethyl ether (3 × 100 mL). The organic phases were combined, washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to afford 2-iodo-6-methoxypyrazine as a white solid (3.5 g, 100% yield). Melting point: 35.7-37.2 °C. NMR hydrogen spectrum (90 MHz, CDCl3): δ 8.40 (1H, single peak), 8.16 (1H, single peak), 3.98 (3H, single peak). Mass spectrum (m/z): 236 (M+), 127, 109 (100%).
