Oxidative metabolism of 1-(2-chloroethyl)-3-alkyl-3- (methylcarbamoyl)triazenes: formation of chloroacetaldehyde and relevance to biological activity

In vitro multitarget activity of sulfadiazine substituted triazenes as antimicrobial, cytotoxic, and larvicidal agents

Multidrug resistance (MDR) causes difficulties in the treatment of infections and cancer. Research and development studies have become increasingly important for the strategy of preventing MDR. There is a need for new multitarget drug research and advancement to reduce the development of drug resistance in drug-drug interactions and reduce cost and toxic effects. This study aimed to determine the effects of multi-target triazene compounds on antibacterial, antifungal, antiviral, cytotoxic, and larvicidal activities were investigated in vitro. A series of 12 novel of 1,3-diaryltriazene-substituted sulfadiazine (SDZ) derivatives were synthesized, and the obtained pure products characterized in detail by spectroscopic and analytic methods (FT-IR, 1 H-NMR, 13 C-NMR, and melting points). The antibacterial and antifungal activities of these derivatives (AH1-12) were determined by broth microdilution method. All derivatives have been evaluated in cell-based assays for cytotoxic and antiviral activities against Modified Vaccinia Virus Ankara. The larvicidal efficacy of these chemical compounds was also investigated by using Lucilia sericata (L. sericata) larvae. Twelve 1,3-diaryltriazene-substituted SDZ derivatives (AH1-12) were designed and developed as potent multitargeted compounds. Among them, the AH1 derivative showed the most antibacterial and antifungal activity. Besides, synthesized derivatives AH2, AH3, AH5, and AH7 showed higher antiviral activity than SDZ. All synthesized derivatives showed higher cytotoxic activity than SDZ. Also, they showed larvicidal activity at 72 h of the experiment. As a result, these compounds might be great leads for the development of next-generation multitargeted agents.

Syntheses and crystal structure of 4-[(pyridin-3-yl)diazen-yl]morpholine and 1-[(pyridin-3-yl)diazen-yl]-1,2,3,4-tetra-hydro-quinoline

Two new heterocyclic 1,2,3-triazenes were synthesized by diazo-tation of 3-amino-pyridine following respectively by coupling with morpholine or 1,2,3,4-tetra-hydro-quinoline. 4-[(Pyridin-3-yl)diazen-yl]morpholine (I), C₉H₁₂N₄O, has monoclinic P2₁/c symmetry at 100 K, while 1-[(pyridin-3-yl)diazen-yl]-1,2,3,4-tetra-hydro-quinoline (II), C₁₄H₁₄N₄, has monoclinic P2₁/n symmetry at 100 K. These 1,2,3-triazene derivatives were synthesized by the organic medium method by coupling reactions of 3-amino-pyridine with morpholine and 1,2,3,4-tetra-hydro-quinoline, respectively, and characterized by ¹H NMR, ¹³C NMR, IR, mass spectrometry, and single-crystal X-ray diffraction. The mol-ecule of compound I consists of pyridine and morpholine rings connected by an azo moiety (-N=N-). In the mol-ecule of II, the pyridine ring and the 1,2,3,4-tetra-hydro-quinoline unit are also connected by an azo moiety. The double- and single-bond distances in the triazene chain are comparable for the two compounds. In both crystal structures, the mol-ecules are connected by C-H⋯N inter-actions, forming infinite chains for I and layers parallel to the bc plane for II.

Crystal structure and spectroscopic properties of (E)-1,3-dimethyl-2-[3-(4-nitrophenyl)triaz-2-enylidene]-2,3-dihydro-1H-imidazole

The title compound (E)-1,3-dimethyl-2-[3-(4-nitrophenyl)triaz-2-enylidene]-2,3-dihydro-1H-imidazole, C11H12N6O2, has monoclinic (C2/c) symmetry at 100 K. This triazene derivative was synthesized by the coupling reaction of 1,3-dimethylimidazolium iodide with 1-azido-4-nitro benzene in the presence of sodium hydride (60% in mineral oil) and characterized by 1H NMR, 13C NMR, IR, mass spectrometry, and single-crystal X-ray diffraction. The molecule consists of six-membered and five-membered rings, which are connected by a triazene moiety (–N=N—N–). In the solid-state, the molecule is found to be planar due to conjugation throughout the molecule. The extended structure shows two layers of molecules, which present weak intermolecular interactions that facilitate the stacked arrangement of the molecules forming the extended structure. Furthermore, there are several weak pseudo-cyclical interactions between the nitro oxygen atoms and symmetry-adjacent H atoms, which help to arrange the molecules.

Properties and Promise of Catenated Nitrogen Systems As High-Energy-Density Materials

The properties of catenated nitrogen molecules, molecules containing internal chains of bonded nitrogen atoms, is of fundamental scientific interest in chemical structure and bonding, as nitrogen is uniquely situated in the periodic table to form kinetically stable compounds often with chemically stable N-N bonds but which are thermodynamically unstable in that the formation of stable multiply bonded N₂ is usually thermodynamically preferable. This unique placement in the periodic table makes catenated nitrogen compounds of interest for development of high-energy-density materials, including explosives for defense and construction purposes, as well as propellants for missile propulsion and for space exploration. This review, designed for a chemical audience, describes foundational subjects, methods, and metrics relevant to the energetic materials community and provides an overview of important classes of catenated nitrogen compounds ranging from theoretical investigation of hypothetical molecules to the practical application of real-world energetic materials. The review is intended to provide detailed chemical insight into the synthesis and decomposition of such materials as well as foundational knowledge of energetic science new to most chemists.

Anticancer Triazenes: from Bioprecursors to Hybrid Molecules

Triazenes are a very useful and diverse class of compounds that have been studied for their potential in the treatment of many tumors including brain tumor, leukemia and melanoma. Novel compounds of this class continue to be developed as either anticancer compounds or even with other therapeutic applications. This review focused on several types of triazenes from the simplest ones like 1,3-dialkyl-3-acyltriazenes to the more complex ones like combi-triazenes with an emphasis on how triazenes have been developed as effective antitumor agents.

Syntheses, structures, electrochemical and optical properties of four transition metal complexes based on the 1-triazolyl-3-benzimidazolyltriazene ligand

The crystal structures, electrochemical and optical properties of four transition metal complexes based on 1-triazolyl-3-benzimidazolyltriazene (H₃TBIT) ligand have been reported.

Crystal structure of (E)-1,3-dimethyl-2-[3-(3-nitro-phen-yl)triaz-2-en-1-yl-idene]-2,3-di-hydro-1H-imidazole

The title compound, C11H12N6O2, a π-conjugated triazene, crystallized with two independent mol-ecules (A and B) in the asymmetric unit. Both mol-ecules have an E conformation about the -N=N- bond and have slightly twisted overall conformations. In mol-ecule A, the imidazole ring is inclined to the benzene ring by 8.12 (4)°, while in mol-ecule B the two rings are inclined to one another by 7.73 (4)°. In the crystal, the independent mol-ecules are linked to each other by C-H⋯O hydrogen bonds, forming -A-A-A- and -B-B-B- chains along [100]. The chains are linked by C-H⋯O and C-H⋯N hydrogen bonds, forming sheets lying parallel to (001). The sheets are linked by further C-H⋯N hydrogen bonds and π-π inter-actions [centroid-centroid distance = 3.5243 (5) Å; involving the imidazole ring of mol-ecule A and the benzene ring of mol-ecule B], forming a three-dimensional framework structure.

Donor-acceptor triazenes: synthesis, characterization, and study of their electronic and thermal properties

A new class of 1,3-disubstituted-triazenes were synthesized by coupling functionalized benzimidazol-2-ylidenes, as their free N-heterocyclic carbenes or generated in situ from their respective benzimidazolium precursors, to various aryl azides in modest to excellent isolated yields (36-99%). Electron delocalization between the two coupled components was studied using UV-vis spectroscopy, NMR spectroscopy, and X-ray crystallography. Depending on the complementarity of the functional groups on the N-heterocyclic carbenes and the organic azides, the respective triazenes were found to exhibit lambda(max) values ranging between 364 and 450 nm. X-ray crystallography revealed bond alteration patterns in a series of triazenes characteristic of donor-acceptor compounds. Triazene thermal stabilities were studied using thermogravimetric analysis and found to be strongly dependent on the sterics of the benzimidazol-2-ylidene component and the electronics of the azide component. Triazenes possessing bulky N-substituents (e.g., neo-pentyl, tert-butyl, etc.) were stable in the solid-state to temperatures exceeding 150 degrees C, whereas analogues with small N-substituents (e.g., methyl) were found to slowly decompose at room temperature. Triazenes featuring electron-rich phenyl azide components decomposed at higher temperatures than their electron-deficient analogues. Products of the thermally induced triazene decomposition reaction were identified as molecular nitrogen and the respective guanidine. Using an isotopically labeled triazene, the mechanism of the decomposition reaction was found to be analogous to the Staudinger reaction.

DFT and ab initio calculations of the vibrational frequencies and visible spectra of triazenes derived from cyclic amines

We present a detailed analysis of the structural, infrared spectra and visible spectra of the 4-substituted aminoazo-benzenesulfonyl azides. The preparation of 4-sulfonyl azide benzenediazonium chloride with cyclic amines of various ring sizes (pyrrolidine, piperidine, 4-methylpiperidine, N-methylpiperazine, morpholine and hexamethyleneimine) have been investigated theoretically by performing HF and DFT levels of theory using the standard 6-31G* basis set. The optimized geometries and calculated vibrational frequencies are evaluated via comparison with experimental values. The vibrational spectral data obtained from solid phase FT-IR spectra are assigned modes based on the results of the theoretical calculations. The observed spectra are found to be in good agreement with the calculations.

Differential inhibition of cellular glutathione reductase activity by isocyanates generated from the antitumor prodrugs Cloretazine™ and BCNU

The antitumor, DNA-alkylating agent 1,3-bis[2-chloroethyl]-2-nitrosourea (BCNU; Carmustine), which generates 2-chloroethyl isocyanate upon decomposition in situ, inhibits cellular glutathione reductase (GR; EC 1.8.1.7) activity by up to 90% at pharmacological doses. GR is susceptible to attack from exogenous electrophiles, particularly carbamoylation from alkyl isocyanates, rendering the enzyme unable to catalyze the reduction of oxidized glutathione. Evidence implicates inhibition of GR as a cause of the pulmonary toxicity often seen in high-dose BCNU-treated animals and human cancer patients. Herein we demonstrate that the prodrug Cloretazine (1,2-bis[methylsulfonyl]-1-[2-chloroethyl]-2-[(methylamino)carbonyl]hydrazine; VNP40101M), which yields methyl isocyanate and chloroethylating species upon activation, did not produce similar inhibition of cellular GR activity, despite BCNU and Cloretazine being equally potent inhibitors of purified human GR (IC(50) values of 55.5 microM and 54.6 microM, respectively). Human erythrocytes, following exposure to 50 microM BCNU for 1h at 37 degrees C, had an 84% decrease in GR activity, whereas 50 microM Cloretazine caused less than 1% inhibition under the same conditions. Similar results were found using L1210 murine leukemia cells. The disparity between these compounds remained when cells were lysed prior to drug exposure and were partially recapitulated using purified enzyme when 1mM reduced glutathione was included during the drug exposure. The superior antineoplastic potential of Cloretazine compared to BCNU in animal models could be attributed in part to the contribution of the methyl isocyanate, which is synergistic with the co-generated cytotoxic alkylating species, while at the same time unable to significantly inhibit cellular GR.

Triazene formation via reaction of imidazol-2-ylidenes with azides

Treatment of N-heterocyclic carbenes (as their free carbenes or generated in situ) with alkyl, aryl, acyl or tosyl azides afforded the respective substituted triazenes in excellent yields.