77168-85-5

77168-84-4

77168-85-5

The general procedure for the synthesis of methyl 5-chloro-6-methylpyrazine-2-carboxylate from methyl 6-methyl-5-oxo-4,5-dihydropyrazine-2-carboxylate was as follows: a solution of methyl 6-methyl-5-oxo-4,5-dihydropyrazine-2-carboxylate was added to POCl3 (20 mL) in DMF (20 mL). The reaction mixture was refluxed for 0.5 h and subsequently poured into ice water. The aqueous layer was extracted with CHCl3 and the organic phase was dried and concentrated with MgSO4. The residue was purified by silica gel column chromatography (eluent: CHCl3) to afford methyl 5-chloro-6-methylpyrazine-2-carboxylate (2.34 g, 52% yield); melting point 49-50 °C.