Synthesis of N-Methylpyrazinium Iodide

Pyrazine (10 g) was dissolved in 25 mL of iodomethane in a glass-stoppered flask. The flask was wrapped with aluminum foil to exclude light and was set aside for one day. The resulting yellow crystals were slurried with 30-40 mL of cold ethanol, and the mixture was filtered. The product was washed with diethyl ether and dried in vacuo overnight. Yield = 15 g.