Synthesis
(i) 2-Amino-3-bromo-5-methylpyrazine (0.374 g) was added to a freshly prepared methanolic solution of sodium methanolate (prepared by reacting sodium metal (0.115 g) with methanol (6 mL)). The reaction mixture was heated and refluxed for 18 h. Subsequently, it was cooled to room temperature and the solvent was removed by distillation under reduced pressure. Water (5 mL) was added to the residue and extracted with dichloromethane (3 x 20 mL). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using dichloromethane as eluent to afford 2-amino-3-methoxy-5-methylpyrazine as a white crystalline solid (0.208 g, 75% yield) with a melting point of 205°C (literature value 67°-69°C). Mass spectrum (positive chemical ionization): m/z 140 ([M + H]+).
References
[1] Patent: US5861401, 1999, A
[2] Patent: US5866568, 1999, A
[3] Patent: US5668137, 1997, A
