General procedure for the synthesis of 2-amino-3-chloropyrazine from 2,3-dichloropyrazine: 2,3-dichloropyrazine (3.5 g, 0.023 mol) was suspended in a mixture of 25% ammonia (20 mL) and tetrahydrofuran (THF, 20 mL) in an autoclave reactor and heated to react for 18 h at 100 °C. The reaction was completed by cooling to room temperature. After completion of the reaction, it was cooled to room temperature and the reaction mixture was concentrated under reduced pressure to a minimum volume. The residue was ground with distilled water (15 mL) and after filtration, the solid product was dried to give 2-amino-3-chloropyrazine as a light yellow crystalline solid (2.75 g, 90% yield). Mass spectrum (electrospray positive ionization mode, ES+) m/z: 130.1. 1H NMR (400 MHz, CDCl3): δ 7.94 (d, J=2.53 Hz, 1H), 7.72 (d, J=2.53 Hz, 1H), 4.90-5.12 (broad single peak, 2H).
