The Synthesis and Reactions of Polyazaaromatics

自去年以来，我们一直在研究1，2，3，4-四嗪及其苯并衍生物的合成方法。以评估我们的反应系统的范围和局限性。N-氨基吡唑被不同的氧化剂氧化得到N-硝基衍生物，再重排成相应的1，2，3-三嗪类化合物。由于该反应体系对多种1，2，3-三嗪类化合物都有效，因此我们将该反应应用于N-氨基-L，2，3-三氮唑的氧化反应。因此，1-氨基-三唑并三氮唑氧化得到了三唑-L，2，3，4-四嗪，这是第一个芳香族四嗪类化合物。该反应被认为是有实际用途的，因为有许多三氮唑的衍生物很容易获得。然而，其他四嗪类化合物不是通过该方法获得的。结果表明，1，2，3，4-四嗪是通过逐级自由基分解而不是协同作用分解的，因此合成的化合物是稳定的，因此我们决定研究另一种氧化剂来与N-氨基化合物反应，发现作为一种生物自由基作为多种生理信号传递体的一氧化氮与氨基化合物以不同的方式反应，这取决于分子氧与NO的量。

Since last year, we have been investigating the synthetic method for 1,2,3,4-tetrazines and their benzo derivatives. In order to evaluate the scope and limitation of our reaction system. N-aminopyrazoles were oxidized byy various oxidizing agents to give N-nitrene derivatives, which were rearranged to corresponding 1,2,3-triazines. Since this reaction system was revealed to be effective for diverse 1,2,3-triazine derivatives, we applied the reaction to the oxidation of N-amino-l, 2,3-triazole. Thus, the oxidation of 1-amino-triazolotriazole afforded the triazolo-l, 2,3,4-tetrazine, which is the first aromatic tetrazine derivative. The reaction was thought to be of practical use because there are many triazole derivatives which are readily available. The other tetrazine derivatives were, however, not obtained by this procedure. The cause of this failure was studied using the molecular orbital calculations, and the results showed that 1,2,3,4-tetrazine would be decomposed via stepwise radical processes rather than concerted ones, thus the compound would be stable if it was synthesized Thus we decided to study another oxidizing agents to react with N-amino compounds, and found that nitric oxide, which has attracted much attention as a biological radical to act as diverse physiological signal transmitters, reacted with amino compounds in various manners depending upon the amount of molecular oxygen vs. NO.