Anticoccidials. VII. Synthesis of 4, 5-Dihydro-5-oxo-2-pyrazinecarboxylic Acid 1-Oxides

Abstract

Hydrolysis of 1, 6-dihydro-6-oxo-2, 3-pyrazinedicarbonitrile (4) gave sodium hydrogen 1, 6-dihydro-6-oxo-2, 3-pyrazinedicarboxylate (6), which was converted to methyl 1, 6-dihydro-6-oxo-2-pyrazinecarboxylate (10) and methyl 4, 5-dihydro-5-oxo-2-pyrazine-carboxylate (12) via a sequence of reactions including decarboxylation and esterification. Although the synthesis of 4, 5-dihydro-5-oxo-2-pyrazinecarboxylic acid 1-oxide (2) from 12 was unsuccessful, its 6-methyl derivative 3 was synthesized from the 5-methyl analog of 4.