Shang, E.; Zhang, J.; Bai, J.; Wang, Z.; Li, X.; Zhu, B.; Lei, X.*
Chem. Commun., 2016, 52, 7028
A transition-metal-free oxidative N–N bond formation strategy was
developed to generate various structurally interesting [1,2,4]triazolo[1,5-
a]benzazoles efficiently. The mechanism of the key oxidative N–N bond
formation was investigated by using an intramolecular competition
reaction. Notably, the first single crystal structure was also obtained
to confirm the structure of 2-aryl[1,2,4]triazolo[1,5-a]benzimidazole
A transition-metal-free oxidative N–N bond formation strategy was developed to generate various structurally interesting [1,2,4]triazolo[1,5- a]benzazoles efficiently. The mechanism of the key oxidative N–N bond formation was investigated by using an intramolecular competition reaction. Notably, the first single crystal structure was also obtained to confirm the structure of 2-aryl[1,2,4]triazolo[1,5-a]benzimidazole
The nitrogen–nitrogen (N–N) bond is widely present in natural products and biologically active nitrogen-rich heterocycles (Fig. 1).1 For example, penipanoid A, isolated from the marine sediment-derived fungus Penicillium paneum SD-44, shows significant cytotoxic activity against the SMMC-7721 cell line.2 Many N–N bond containing drugs, such as the anti-inflammatory drug Celebrex and antihyperglycemic drug Januvia are among the top selling medicines.3 Therefore, the study of structurally novel and biologically active N–N bond containing heterocycles has drawn significant attention from both academia and pharmaceutical industry. [1,2,4]Triazolo[1,5-a]benzimidazole is an interesting type of N–N bond containing heterocycle which shows promising biological activities, such as antifungal, anti-inflammatory and analgesic,4 as well as anti-histamine effects.5 Although three methods have been reported for the synthesis of this type of structure, they all suffered either long synthetic routes or harsh reaction conditions and only a handful of substrates were prepared (Scheme 1).6 The lack of efficient synthetic methodology hindered the application of this type of heterocycles in chemical biology and drug discovery