Reaction of Nitrilimines with 2-Substituted Aza-heterocycles. Synthesis of Pyrrolo [1, 2-a] pyridine and Pyrimido [2, 1-d] 1, 2, 3, 5-tetrazine

The reaction of nitrilimine 6a with ethyl pyridine-2-acetate (7) gave thecorresponding pyrrolo&91;1,2-a&93;pyridine 8, while the reaction of 6b containing an estermoiety afforded the acyclic adduct 9. The reaction of 6a with 2-aminopyrimidine (10)gave the novel unexpected pyrimido&91;2,1-d&93;1,2,3,5-tetrazine 11. Acyclic adducts 16 and17 were obtained from the reaction of 6b with 2-cyanomethylbenzimidazole (14) and 2-aminobenzimidazole (15), respectively