SYNTHESIS OF PYRAZINO[2,3-C]ISOQUINOLINECARBOXYLIC ACIDS AND RELATED-COMPOUNDS

1-Methylisoquinoline-3,4-diamine has been synthesized and condensed with alpha-dicarbonyl compounds to give the fused pyrazine ring. Oxidation of methyl groups gives the 3- and 6-carboxylic acids. Nitration occurs in the benzenoid ring to give the single 10-nitro product, and formation of an unusual 6-trinitromethyl compound is also reported.