Abstract The reaction of o-phenylenediamine with a β-ketoacid, leads in most cases to quinoxalinones. Their structure has been determined as well as that of their corresponding hydrazones. The reaction of hydrazine with these quinoxalinones gives dihydropyridazino [3, 4-b] quinoxalines, the structure of which has been ascertained. It has been shown that among the six possible formulas, the only 1, 2-dihydro structure fits with the spectroscopic ...
![10-methyl-3-phenyl-5H-pyridazino[4,3-b]quinoxaline Structure](https://image.chemsrc.com/caspic/434/105689-07-4.png)
