Synthesis of Derivatives of Pyrazino(1,2-a)pyrimidin-4-ones.

3-Alkoxy-2-aminopyrazines have been condensed with ethyl ethoxymethylenemalonate and isopropylidene methoxymethylenemalonate to afford 9-alkoxypyrazino[1,2-a]pyrimidin-4-ones substituted in the first case by an ethoxycarbonyl group at 3 position.