-3-(2'-Cyanophenoxy)-1, 2, 4-triazines and 7-(2'-cyanophenoxy)-6-azalumazines undergo intramolecular Diels-Alder reactions to yield novel polycyclic pyrazines and lumazines. However, the analogous 5-(2'-cyanophenoxy)-1, 2, 4-triazines fail to undergo cycloaddition, preventing access to the unknown benzfuro [2, 3-e]-1, 2, 4-triazine system. Substitution of oxime ethers for nitriles on the dienophilic sidechains of the respective Diels-Alder ...