Aim: Novel thiazole hybrids were synthesized via thiazolation of 4-phenylthiosemicarbazone (4). Materials & methods: The anticancer activity against the NCI 60 cancer cell line panel. Results: Methyl 2-(2-((1-(naphthalen-2-yl)ethylidene)hydrazineylidene)-4-oxo-3-phenylthiazolidin-5-ylidene)acetate (6a) showed significant anticancer activity at 10 μM with a mean growth inhibition (GI) of 51.18%. It showed the highest cytotoxic activity against the ovarian cancer OVCAR-4 with an IC50 of 1.569 ± 0.06 μM. Compound 6a inhibited PI3Kα with IC50 = 0.225 ± 0.01 μM. Moreover, compound 6a revealed a decrease of Akt and mTOR phosphorylation in OVCAR-4 cells. In addition, antibacterial activity showed that compounds 11 and 12 were the most active against Staphylococcus aureus. Conclusion: Compound 6a is a promising molecule that could be a lead candidate for further studies.
Novel naphthalene-azine-thiazole hybrids 5-12 were synthesized via late-stage thiazolation of the corresponding 4-phenylthiosemicarbazone 4. Compound 6a showed significant anticancer activity at single-dose screening and yielded excellent inhibitory activity with a mean GI of 51.18%. Compound 6a showed the highest cytotoxic activity against OVCAR-4 with an IC50 of 1.569 ± 0.06 μM. Moreover, compound 6a exhibited an IC50 of 31.89 ± 1.19 μM against normal ovarian cell line (OCE1) and a selectivity index of 19.1. Compound 6a inhibited PI3Kα with IC50 = 0.225 ± 0.01 μM compared with alpelisib (IC50 = 0.061 ± 0.003 μM). Moreover, compound 6a revealed a powerful decrease of Akt and mTOR phosphorylation in the OVCAR-4 cell line. The cell cycle analysis showed that compound 6a caused an arrest at the G2/M phase. The compound also increased the total apoptosis by 26.8-fold and raised the level of caspase-3 by 4.34 times in OVCAR-4. In addition, antibacterial activity was estimated against Gram-positive and Gram-negative bacterial strains. Compounds 11 and 12 were the most active derivatives, with MIC value of 256 μg/ml against Staphylococcus aureus. Molecular docking was done and showed that 6a interlocked and fitted well into the ATP binding site of PI3Kα kinase (Protein Data Bank ID: 4JPS) with a fitness value (-119.153 kcal/mol) and forms the key H-bonds with Val851 and Ser854 like the marketed PI3Kα inhibitor alpelisib. Consequently, 6a is the most promising molecule that could be a lead candidate for further studies.

During the last decades, five or six member rings azaheterocycles compounds appear to be an extremely valuable source of antifungal agents. Their use seems to be a very attractive solution in antifungal therapy and to overcome antifungal resistance in agriculture. The present review highlights the main results obtained in the field of hybrid and chimeric azine (especially pyridine, quinoline, phenanthroline, bypyridine, naphthyridine and their fused derivatives) derivatives presented in scientific literature from the last 10 years, with emphasis on antifungal activity of the mentioned compounds. A special attention was played to hybrid and chimeric azole-azine class, having in view the high antifungal potential of azoles.
[Box: see text].

Indenone azines, in which the exocyclic C=C bond in dibenzopentafulvalene is replaced by an azine moiety (C=N-N=C), have been synthesized as novel electron-accepting π-conjugated scaffolds. Structural modulation at the 7,7\'-positions of indenone azines enabled stereoselective syntheses of diastereomers in which the configurations of the two C=N bonds are E,E or Z,Z. X-ray crystallographic analyses revealed that all the indenone azines exhibit high coplanarity in contrast to the twisted frameworks of dibenzopentafulvalene derivatives, resulting in the formation of densely π-stacked structures. Electrochemical measurements and quantum chemical calculations revealed the electron-accepting character of indenone azines comparable to isoindigo dyes. In particular, the intramolecular hydrogen bonds of 7,7\'-dihydroxy-substituted derivatives impart enhanced electron-accepting character and significantly red-shifted photoabsorption. This study demonstrates that indenone azines represent a promising candidate as electron-accepting building blocks for optoelectronic materials.

Most hydrazone compounds prefer the azine tautomeric states. However, oxygen-/sulfur-substituted compounds prefer hydrazone tautomers. In this study, density functional theory at M062X level with the basis set of 6-311 +  + g(2d, 2p), with MP2/cc-pVTZ for reference, was used to investigate the different tautomeric mechanisms between hydrazone and azine forms with oxygen, sulfur, carbon, and nitrogen as negative centers. The energetic stabilities are in the order as oxygen- < sulfur- < imine- < amidino- < carbene-substituted hydrazones with respect to their azine tautomeric structures. Resonance of the molecular structures might be the geometrical basis for their energy stabilities and were estimated based on HOMED indices. Further, the increased proton affinities in the trend as hydroxyl < sulfhydryl < imine terminal groups account for their increasing azine preferences. Proton release was examined for the reversible equilibrium from azine to hydrazone by calculating the transition energy barrier of H transfer. It is favorable to form hydrazone tautomers for oxygen and sulfur containing groups, while it is less favorable for amino-substituted ones. Azine form is the most stable tautomer for methyl substituted.

The field of molecular transition metal complexes with redox-active ligands is dominated by compounds with one or two units of the same redox-active ligand; complexes in which different redox-active ligands are bound to the same metal are uncommon. This work reports the first molecular coordination compounds in which redox-active bisguanidine or urea azine (biguanidine) ligands as well as oxolene ligands are bound to the same cobalt atom. The combination of two different redox-active ligands leads to mono- as well as unprecedented dinuclear cobalt complexes, being multiple (four or six) center redox systems with intriguing electronic structures, all exhibiting radical ligands. By changing the redox potential of the ligands through derivatisation, the electronic structure of the complexes could be altered in a rational way.

Oxidative C-H/C-H coupling reactions of dipyrromethanes with azines in the presence of a heterophase oxidative photocatalytic system (O2/TiO2/visible light irradiation) were carried out. As a result of cyclization of obtained compounds with boron trifluoride etherate, new hetaryl-containing derivatives of 4,4-difluoro-4-boron-3a,4a-diaza-s-indacene were synthesized. For the obtained compounds, absorption and luminescence spectra, quantum yields of luminescence as well as cyclic volt-amperograms were measured.

In this work, we demonstrate that rational decoration of pore walls of the metal-organic frameworks (MOFs) with azine and dihydro-tetrazine functions is a very practical strategy for high capacity removal of both neutral and basic nitrogen-containing compounds (NCCs) from model oil. Its performance is even much better than the MOFs with high surface area, open metal sites, and different functional groups such as amine, hydroxyl, carboxy, and sulfonate. For this aim, a number of isostructure functional MOFs (FMOFs) have been synthesized. Among them, TMU-5 (with formula [Zn(OBA)(BPDH)0.5] n·1.5DMF, where H2OBA = 4,4\'-oxybis(benzoic acid) and BPDH = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene) and TMU-34 (with formula [Zn(OBA)(H2DPT)0.5] n·DMF H2DPT = 3,6-di(pyridin-4-yl)-1,4-dihydro-1,2,4,5-tetrazine) show high affinity toward neutral and basic NCCs, respectively. Dihydro-tetrazine-decorated TMU-34 shows good affinity toward basic NCCs [pyridine (PYD) and quinoline (QUI)] because of hydrogen bonding of dihydro-tetrazine (-NH)···(N) basic NCCs. TMU-34 can adsorb about 619 and 632 mg g-1 PYD and QUI, respectively. On the other hand, azine-methyl-functionalized TMU-5 shows very high affinity to neutral NCCs [pyrrole (PRR) and indole (IND)] owing to strong hydrogen bonding of azine-methyl (Me-C═N-N═C-Me)···(NH) neutral NCCs. TMU-5 can adsorb 518 and 578 mg g-1 PRR and IND, respectively. These numbers are among the best reported data in this area and even reveal higher significance of the host-guest interaction when we consider moderate surface of these FMOFs. These results have been achieved by our \"application-directed cavity functionalization\" approach through decoration of MOF structures by suitable organic functional groups for specific purposes.

Five new mononuclear iron(II) tris-ligand complexes, and four solvatomorphs, have been made from the azine-substituted 1,2,4-triazole ligands (Lazine ): [FeII (Lpyridazine )3 ](BF4 )2 (1), [FeII (Lpyrazine )3 ](BF4 )2 (2), [FeII (Lpyridine )3 ](BF4 )2 (3), [FeII (L2pyrimidine )3 ](BF4 )2 (4), and [FeII (L4pyrimidine )3 ](BF4 )2 (5). Single-crystal XRD and solid-state magnetometry reveal that all of them are low-spin (LS) iron(II), except for solvatomorph 5⋅4 H2 O. Evans method NMR studies in CD2 Cl2 , (CD3 )2 CO and CD3 CN show that all are LS in these solvents, except 5 in CD2 Cl2 (consistent with L4pyrimidine imposing the weakest field). Cyclic voltammetry in CH3 CN vs. Ag/0.01 m AgNO3 reveals an, at best quasi-reversible, FeIII/II redox process, with Epa increasing from 0.69 to 0.99 V as the azine changes: pyridine< pyridazine<2-pyrimidine<4-pyrimidine< pyrazine. The observed Epa values correlate linearly with the DFT calculated HOMO energies for the LS complexes.

Azine based new colorimetric sensor 1 for the detection of gasotransmitter H2S has been reported. Sensor 1 used to detect the H2S with a remarkable red shift of 105 nm in the absorption spectra with a colour change from light yellow to brown red. Importantly, rare example of azine derivative has been used as a colorimetric probe for H2S detection using deprotonation mechanism. H2S induced deprotonation of one of the -OH proton followed by a change in resonance of 1 is responsible for the ratiometric spectral and colour change. The detection response was quick and the LOD calculated as 18.2 μM. Sensor 1 was also explored in the detection of H2S in biological fluids such as human serum and mouse serum. Moreover, for the first time, we have shown the applicability of H2S for the construction of half subtractor molecular logic gate.

Isatin oxamohydrazide (L) reacted with the aqueous solution of silver nitrate at room temperature afforded the polymeric silver(I) nitrato complex, [Ag2L\'(NO3)2] n , (1) of the azine ligand (L\'). Similarly, the reaction of L with silver(I) perchlorate gave the [Ag2L\'2(ClO4)2] n , (2) coordination polymer. Careful inspection of the crystals from the nitrato complex preparation showed the presence of another crystalline product which is found to be [Ag(Isatin-3-hydrazone)NO3], (3) suggesting that the reaction between silver(I) nitrate and L proceeds first by the hydrolysis of L to the isatin hydrazone which attacks another molecule of L to afford L\'. Testing metal salts such as Ni2+, Co2+, Mn2+, Cu2+ and Cd2+ did not undergo any reaction with L either under the same reaction conditions or with heating under reflux up to 24 h. Treatment of the warm alcoholic solution of L with few drops of 1 : 1 (v/v) hydrochloric acid gave the free ligand (L\') in good yield. The [Ag2L\'(NO3)2] n complex forms a two-dimensional infinite coordination polymer, while the [Ag2L\'2(ClO4)2] n forms one-dimensional infinite chains with an alternating silver-azine backbone. Quantitative analysis of the intermolecular interactions in their crystals is made using Hirshfeld surface analysis. Density functional theory studies were performed to investigate the coordination bonding in the studied complexes.