Gold(I) complexes with 1,3-substituted imidazole-2-ylidene and benzimidazole-2-ylidene ligands of the type NHC-Au-L (NHC = N-heterocyclic carbene L = Cl or 2-mercapto-pyrimidine) have been synthesized and structurally characterized. The compounds were evaluated for their antiproliferative properties in human ovarian cancer cells sensitive and resistant to cisplatin (A2780S/R), as well in the nontumorigenic human embryonic kidney cell line (HEK-293T), showing in some cases important cytotoxic effects. Some of the complexes were comparatively tested as thioredoxin reductase (TrxR) and glutathione reductase (GR) inhibitors, directly against the purified proteins or in cell extracts. The compounds showed potent and selective TrxR inhibition properties in particular in cancer cell lines. Remarkably, the most effective TrxR inhibitors induced extensive oxidation of thioredoxins (Trxs), which was more relevant in the cancerous cells than in HEK-293T cells. Additional biochemical assays on glutathione systems and reactive oxygen species formation evidenced important differences with respect to the classical cytotoxic Au(I)-phosphine compound auranofin.

BackgroundThe enteric glia network may be involved in the pathogenesis of inflammatory bowel disease (IBD). Enteric glia cells (EGCs) are the major source of glial-derived neurotrophic factor (GDNF), which regulates apoptosis of enterocytes. The aim of the study was to determine the distribution of EGCs and GDNF during gut inflammation and to elucidate a possible diminished enteric glia network in IBD.MethodsThe expression of glial fibrillary acidic protein (GFAP) in colonic biopsies of patients with IBD, controls and patients with infectious colitis was detected by immunohistochemistry and Western blot. Tissue GDNF levels were measured by ELISA.ResultsThe expression of GFAP and GDNF in the mucosal plexus is highly increased in the inflamed colon of patients with ulcerative colitis (UC) and infectious colitis. Although the GDNF and GFAP content are increased in Crohn's disease (CD), it is significantly less. Additionally the non-inflamed colon of CD patients showed a reduced GFAP and no GDNF expression compared to controls and the non-inflamed colon of UC patients.ConclusionsGFAP and GDNF as signs of activated EGCs are increased in the inflamed mucosa of patients with UC and infectious colitis, which underline an unspecific role of EGC in the regulation of intestinal inflammation. The reduced GFAP and GDNF content in the colon of CD patients suggest a diminished EGC network in this disease. This might be a part of the pathophysiological puzzle of CD.

In the development of new energetic materials, the main challenge is the combination of high energy content with chemical and mechanical stability, two properties that are often contradictory. In this study, the syntheses and comprehensive characterizations of 4,5-bis(tetrazole-5-yl)-1,2,3-triazole and the novel 4,5-bis(1-hydroxytetrazole-5-yl)-1,2,3-triazole, as well as their energetic properties, are presented, combining the advantages of the more energetic tetrazole and the more stable 1,2,3-triazole rings. Nitrogen-rich salts of both compounds were synthesized to investigate their detonation performances and combustion behavior calculated by computer codes for potential application in erosion-reduced gun propellant mixtures due to their high nitrogen content. The structures of several of the compounds were studied by single-crystal X-ray diffraction and, especially in the case of 4,5-bis(tetrazol-5-yl)-1,2,3-triazole, revealed the site of deprotonation.

There are great demands to develop explosives with higher performance accompanied by reduced sensitivities towards external stimuli, higher thermal stability and improved environmental acceptability. This contribution presents modified nitramines, which were investigated by nucleophilic substitution reactions of potassium salts of 5‐amino‐3‐nitro‐1,2,4‐triazole, 3,5‐dinitro‐1,2,4‐triazole, 3,5‐dinitroimidazole, 2,4‐dinitroimidazole, 4‐amino‐3,5‐dinitropyrazole, 3,5‐dinitropyrazole, 3,4‐dinitropyrazole and 3,4,5‐trinitropyrazole on 1,3‐dichloro‐2‐nitrazapropane. The energetic compounds were comprehensively characterized and their detonation parameters were calculated by the EXPLO5 code. Heats of formation were calculated by the atomization method using CBS‐4M electronic enthalpies. The presented compounds show detonation performances comparable to pentaerythritol tetranitrate (PETN). In addition, they possess high thermal stabilities and low sensitivities, which make them interesting for further investigations and possible applications as insensitive, high‐energy dense materials.

This study presents the preparation of the novel nitrogen-rich compound 5-(5-amino-2H-1,2,3-triazol-4-yl)-1H-tetrazole (5) from commercially available chemicals in a five step synthesis. The more energetic derivatives with azido (6) and nitro (7) groups, as well as a diazene bridge (8) were also successfully prepared. The energetic compounds were comprehensively characterized by various means, including vibrational (IR, Raman) and multinuclear ((1)H, (13)C, (14)N, (15)N) NMR spectroscopy, mass spectrometry and differential thermal analysis. The sensitivities towards important outer stimuli (impact, friction, electrostatic discharge) were determined according to BAM standards. The enthalpies of formation were calculated on the CBS-4M level of theory, revealing highly endothermic values, and were utilized to calculate the detonation parameters using EPXLO5 (6.02).