Selective Bromocyclization of 5-Amino-4-Alkenyl-1,2,4-Triazole-3-Thione

Here, we present a study on the regioselectivity cyclization of 5-amino-4-alkenyl-1,2,4-triazole-3-thiones. The presence of various nucleophilic centers causes the possibility of cyclization of an alkenyl fragment on different heteroatoms and the formation of a few alternative structures. Elemental bromine was utilized as an electrophilic agent, and two 6-(bromomethyl)-6-R-5,6-dihydro[1,3]thiazolo[2,3-c][1,2,4]triazol-3-amine hydrobromide salts were obtained as the only products when taking reaction in chloroform, acetic acid, or acetonitrile. The 1H and 13C APT NMR spectra analysis proved the formation of the 1,3-thiazolinium ring upon cyclization reaction. DFT calculations at the ωB97X-D3/6-311G(d,p) level of theory were utilized to analyze molecular electrostatic potential, electron localization function, and Hirshfeld atomic partial charges the intermediate bromonium cation. These theoretical calculations explain the experimentally observed regioselectivity.

Activating Effect of Aluminum Chloride in the Technology of Poly-Sulfides and Materials Based on them

The paper investigates the influence of an electrophilic agent in the inorganic polysulfide technology. A tight contact between the modified silicate filler and sulfur (when heated and then pressed) results in the appearance of new interatomic bonds and interphase interaction forces to ensure the best possible structure formation in a system in the micro and macro level. Cross-linking of silica gel by disulfide fragments shows greater stability. The activation energies were calculated for insertion of diatomic sulfur (singlet and triplet) by an oxygen atom and a silicon atom, with the substitution of OH-group, as well as for addition of diatomic sulfur to the surface of silica gel modified with aluminum chloride. Aluminum chloride acts as an activator for both a silica-containing material and sulfur, and encourages the chemical interaction between the components, and formation of polysulfides and sulfur materials from them, which have high physical mechanical properties.

Technology and Properties of Composite Materials with Modifier of Chloride Aluminum

The paper discusses the important issues concerning recycling of industrial sulfur waste and bottom ash. The process flow diagram was designed to form protective coatings on cement concrete by impregnation with molten sulfur, which featured high strength, performance properties and corrosion resistance. The process parameters were specified. The addition of bottom ash slag to cement concrete not only offers a means for recovering waste from thermal power stations, but also increases the material strength. Besides, the impregnation process provides low thermal conductivity for concrete while giving the material high heat insulation. A higher strength of the samples containing bottom ash slag results from a high dispersity and reactive surface of bottom ash slag. The paper investigates the influence of the electrophilic agent (aluminum chloride) on the properties of sulfur binder. It was shown that addition of aluminum chloride encouraged the formation of a more effective protective coating that gave the samples of cement concrete higher strength, density, water resistance. The electrophilic agent stimulated the synthesis process for inorganic sulfides and composite materials based on them. It was found that addition of the electrophilic agent (aluminum chloride) reduced the viscosity of molten sulfur significantly, which was attributed to the formed short-chain sulfur radicals. Such a melt has a relatively high penetration capability to ensure the formation of a high-quality protective coating.

Absolute Amounts and Status of the Nrf2-Keap1-Cul3 Complex within Cells

The transcription factor Nrf2 (NF-E2-related-factor 2) is essential for the oxidative and electrophilic stress responses. Keap1 (Kelch-like-ECH-associated-protein 1), an adaptor for a cullin-3 (Cul3)-based ubiquitin ligase, regulates Nrf2 activity through proteasomal degradation, and acts as a sensor for oxidative and electrophilic stresses. The Keap1-Cul3 complex is a critical regulator of the cellular Nrf2 level, and yet quantitative information regarding their endogenous intracellular concentrations in homeostatic conditions and during stress responses is unknown. We analyzed the absolute amounts of the Nrf2, Keap1, and Cul3 proteins in five murine cell lines by comparison with serial dilutions of purified recombinant protein standards in combination with quantitative immunoblot analyses. In the basal state, the amount of Nrf2 was maintained at lower levels than those of Keap1 and Cul3 proteins, whereas the electrophilic agent diethylmaleate dramatically increased Nrf2 to a level greater than that of Keap1 and Cul3, resulting in the accumulation of Nrf2 in the nucleus. In contrast, Keap1 and Cul3 did not display any changes in their abundance, subcellular localization, or interaction in response to electrophilic stimuli. Our results demonstrate that the regulation of the Nrf2 protein level during stress responses is mediated by the activity but not the composition of the Nrf2-Keap1-Cul3 complex.