The chemistry of azides is a speedily developing research area. The results in azides investigation are important for the creation of new fluorescent tags, bioconjugative techniques, new synthetic methodologies and new compounds with promising biological properties.
Firstly, organic azides are important building blocks for the synthesis of triazoles by Cu-catalyzed azide-alkyne cycloaddition (CuAAC), [1,2] strain-promoted azide-alkyne cycloaddition (SPAAC) [3-4] and organocatalytic interaction with carbonyl compounds [5]. However other types of synthetic transformations such as reduction to amines, Staudinger reaction and nitrene generation followed by different transformations of these highly reactive species should not be forgotten. [6,7] The unique role of azide chemistry is illustrated by applicability of all reaction mentioned above for biosystems that is caused by the bioorthogonality of azide functional group. Following this way, the chemistry of azides is employed in bioconjugation using CuAAC, SPAAC, Staudinger ligation and photoaffinity labeling. [8]
An important area of azides application is using them as fluorogenic probes – molecules, which being bonded to the target, change one of their fluorescence parameters [9]. It should be noted that both the target and the fluorophore must have functional groups which are able to react with each other under mild conditions. During last decade, azido-substituted heterocycles have been broadly studied in this direction. Organic azides can act as fluorogenic labels due to their ability to react with alkynes through 1,3-dipolar cycloaddition affording 1,2,3-triazoles with dissimilar fluorescent properties [10, 11]. Besides, the novel approach to obtain new specific bioactive compound based on 1,2,3-triazoles are able to link promising heterocyclic molecule with natural product. The hybrids may be more active than their parent compounds and be able to overcome drug resistance [12].
In the previous research of Prof. Tsogoeva group, artemisinin-based hybrids were investigated [13-15] in particular artemisinin–(iso)quinolone hybrids [16]. According to our previous research of 4-azidocinnolines [17], we suggested that artemisinin–cinnoline hybrids are promising compounds due to similarity of heterocyclic core. Taking into account that the cinnoline core can be found both in biologically active compound [18-19], the development of a synthetic route towards azidocinnolines its artemisinin hybrids could lead to new biologically active molecules with remarkable properties.