Aza-2-diènes-1,3 3. Nouvelles voies d'accès à des amino-2-pyrazines substituées

2-Aza-1,3-dienes. A New Approach to Substituted 2-Aminopyrazines Treatment of enamines by tosylated isonitrosomalono derivatives gives access to 5-dialkylamino-1, 1-dicyano 2-aza-1,3-dienes (or 1-methoxycarbonyl analogous) which are precursors of various regiospecific 5,6-substituted 2-amino-3-cyano (or methoxycarbonyl) pyrazines. Some examples of utilisation of these intermediates for synthesis of lumazines, pteridines, and other bicyclic skeletons are described.