Quinoxalinediones. I. Synthesis of 6-methyl-5,8-quinoxalinediones (original) (raw)

1964, Journal of Heterocyclic Chemistry

Various synthetic routes were investigated as potential methods of preparation of 6methyl-5, 8-quinoxalinediones which could be useful a s antimetabolites of vitamin K. The preparation of 2,3-dimethyl-5,Bquinoxalinedione (II) was achieved by the condensation of 2,3-diamino-l,4-dimethoxybenzene with diacetyl. Demethylation was accomplished by the use of aluminum chloride in benzene and the resulting hydroquinone (l) was oxidized with dry silver oxide to the quinone (II). An analogous synthetic route could not be used to prepare 2,3,6-trimethy1-5,8-quinoxalinedione (VII). 6-Methyl-5,8-quinoxalinediones were prepared from 2,3-dinitro-4-methoxy-6-methylacetanilide (III) which was reduced and condensed with appropriate carbonyl compounds. Acid hydrolysis yielded aminophenols which were oxidized to (VII) and (VIII) with chromic acid. The ultraviolet and infrared spectra of the compounds prepared a r e recorded.