Quinoxalin-3-one-2-carboxylic acid

The condensation of a-ketoacids and o-phenylenediamines gives quinoxalin-2-ones,7 and mesoxalic acid and o-phenylenediamine undergo the expected condensation reaction to give quinoxalin-3-one-2-carboxylic acid (1). With sodium mesoxalate an anomalous reaction occurs, the initial products (1) and l,2-dihydrobenzimidazole-2,2-dicarboxylic acid (2) undergo an intermolecular hydrogen transfer reaction to yield l,2,3,4-tetrahydro-3-oxoquinoxaline-2-carboxylic acid (3) and benzimidazole-2-carboxylic acid (4).8... 

Quinoxalin-4-ones, methylation of, 255 Quinoxalin-3-one 1-oxides, 218, 238-239 Quinoxalin-3-one-2-carboxylic acid, 205, 207... 

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