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Many heterocyclic compounds can be synthetized using diaza-1,3-butadienes (DADs) as key structural precursors. Isolated and in situ diaza-1,3-butadienes, produced from their respective precursors (typically imines and hydrazones) under a variety of conditions, can both react with a wide range of substrates in many kinds of reactions. Most of these reactions discussed here include nucleophilic additions, Michael-type reactions, cycloadditions, Diels–Alder, inverse electron demand Diels–Alder, and aza-Diels–Alder reactions. This review focuses on the reports during the last 10 years employing 1,2-diaza-, 1,3-diaza-, 2,3-diaza-, and 1,4-diaza-1,3-butadienes as intermediates to synthesize heterocycles such as indole, pyrazole, 1,2,3-triazole, imidazoline, pyrimidinone, pyrazoline, -lactam, and imidazolidine, among others. Fused heterocycles, such as quinazoline, isoquinoline, and dihydroquinoxaline derivatives, are also included in the review.

A series of 2-(haloalkyl)-3-azidomethyl and 6-azido chromones has been synthetized, characterized and studied by theoretical (DFT calculations) and spectroscopic methods (UV-Vis, NMR). The crystal structure of 3-azidomethyl-2-difluoromethyl chromone, determined by X-ray diffraction methods, shows a planar framework due to extended π-bond delocalization. Its molecular packing is stabilized by F···H, N···H and O···H hydrogen bonds, π···π stacking and C–O···π intermolecular interactions. Moreover, AIM, NCI and Hirshfeld analysis evidenced that azido moiety has a significant role in the stabilization of crystal packing through weak intermolecular interactions, where analysis of electronic density suggested closed-shell (CS) interatomic interactions.

The work seeks to identify molecules with inhibitory activity against the DNA gyrase of Gram-negative microorganisms resistant to fluoroquinolones. Previously designed compounds were used to study antimicrobial potential in silico. Molecular docking was performed with nine new ciprofloxacin analog molecules, optimized through the PM6/ZDO theory level, in GyrA wild type (WT) and mutant type (MT) of C. jejuni, E. coli (6RKU PDB ID), N. gonorrhoeae, P. aeruginosa, S. enteritidis, and S. typhi. The molecule with the highest affinity for GyrA was selected based on its binding free energy and inhibition constant. In addition, a retrospective docking was carried out, to guarantee the correct affinity of the ligand to the receptor at the defined binding site. The results show a molecule with greater affinity for GyrA in five microorganisms, showing a binding free energy of less than −7.0 kcal/mol, suggesting a good antibacterial activity in silico.