1,6-Diazabicyclo[4.4.4]tetradecane, which was extensively studied by Alder et al. in the 1970–1980 s, exhibits very interesting redox and protonation properties. We intended to synthesize its benzo analog as an extension of our studies on aza cryptands; however, by following Alder’s synthetic route, we obtained only tricyclo[4.4.4.0]tetradecane tribenzo analog. Therefore, the target compound was synthesized from 2,11-diaza[3.3]--cyclophane. The proton-template synthesis of the benzo analog was straightforward and clean. The optimized structures of the products were obtained by DFT calculations since crystal structures were not available. The results showed that the NH proton of the ammonium salt was biased towards the nitrogen atom on one side. This is in contrast to the internally protonated 1,6-diazabicyclo[4.4.4]tetradecaneH, in which the proton is located exactly halfway between two N atoms. Thus, the properties of the tribenzo analog is different from those of their parent aliphatic bicyclic diamine, and the basicity is comparable to that of ordinary amines.

中文翻译：

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三苯并-1,6-二氮杂双环[4.4.4]十四烷的合成

1,6-二氮杂双环[4.4.4]十四烷，Alder等人对其进行了广泛研究。在 1970-1980 年代，表现出非常有趣的氧化还原和质子化特性。我们打算合成其苯并类似物，作为我们对氮杂穴状配体研究的延伸；然而，按照Alder的合成路线，我们只得到了三环[4.4.4.0]十四烷三苯并类似物。因此，以2,11-二氮杂[3.3]-环芳为原料合成了目标化合物。苯并类似物的质子模板合成简单明了。由于晶体结构未知，产品的优化结构是通过DFT计算获得的。结果表明，铵盐的NH质子偏向一侧的氮原子。这与内部质子化的 1,6-二氮杂双环[4.4.4]十四烷 H 形成鲜明对比，其中质子正好位于两个 N 原子之间的中间。因此，三苯并类似物的性质不同于其母体脂肪族双环二胺，并且碱性与普通胺相当。