Synthesis
GENERAL METHOD: 2-Pyrazinecarboxylic acid (5.5 mmol) was dissolved in 90 mL of ethanol, 15 mL of concentrated H2SO4 was added and heated at reflux for 3 hours. After completion of the reaction, the reaction solution was neutralized with saturated Na2CO3 solution and filtered to remove insoluble material. The filtrate was concentrated under reduced pressure and subsequently extracted with four 30 mL dichloromethane. The organic phases were combined, washed with 10 mL of water and dried over anhydrous MgSO4. Dichloromethane was evaporated under reduced pressure to give ethyl pyrazine-2-carboxylate (8b) with a melting point of 46-47 °C (literature value 48-49 °C, Yoshino et al.)
References
[1] Medicinal Chemistry Research, 2015, vol. 24, # 6, p. 2529 - 2550
[2] Journal of Organic Chemistry, 1994, vol. 59, # 24, p. 7284 - 7291
[3] Journal of the Chemical Society, Dalton Transactions, 2002, # 21, p. 4048 - 4054
[4] ChemMedChem, 2017, vol. 12, # 12, p. 972 - 985
