Cyclization of crotyl phenyl sulfide in the presence of acid catalysts

Crotyl phenyl sulfide is converted to 2-ethyl-2,3-dihydrobenzothiophene and 2- and 4-methylthiochromans in the presence of -Al₂O₃ and 5, 10, and 20% ZnCl₂/Al₂O₃ at 300°C and is also isomerized to 1-butenyl- and 3-butenyl phenyl sulfides and cleaved to thiophenol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1337–1339, October, 1973.     

Comparing the geomagnetic thresholds of cosmic rays for two empirical models of the magnetosphere during the period of an extreme geomagnetic storm in November 2003

The accuracy of determining the geomagnetic cutoff rigidity (the geomagnetic threshold) is closely related to that of describing the magnetic field of the magnetosphere with the model used for calculations. Geomagnetic thresholds are calculated for two empirical models of the magnetosphere, Ts0l and Ts04, constructed on the basis of the same initial experimental data. The Ts01 model describes the average magnetosphere for certain conditions in the solar wind and interplanetary field. The Ts01 model focuses on describing the large-scale evolution of magnetospheric currents during a storm. A comparison of the geomagnetic thresholds for Ts0l and Ts04 with experimental thresholds calculated by the Spectrographic Global Survey from data of the CR global network stations shows that the Ts01 model describes the magnetic field of the magnetosphere more realistically. Our study was conducted for the period of a strong geomagnetic storm in November 2003.     

Microwave absorption spectra and the problem of the crystal field in tetragonal compounds HoBa2Cu3O x (x = 6.0, 6.3)

The resonance microwave absorption at wavelengths 871, 406, 305, and 118 μm in tetragonal layered perovskites HoBa₂Cu₃O _x (x = 6.0, 6.3) in pulsed magnetic fields up to 40 T has been detected. This absorption is caused by the electronic transitions between low lying levels of the Ho³⁺ ion in the crystal field. The positions and intensities of the basic resonance absorption lines for the crystal with x = 6.0 in the magnetic field oriented along the tetragonal axes are adequately described in terms of the tetragonal crystal field with known interaction parameters. To explain the weaker absorption lines, it is necessary to take into account the effect of the inhomogeneous orthorhombic and monoclinic components of the crystal field, which are due to disorder in the oxygen subsystem. This effect is more pronounced in the absorption spectra of the crystal with x = 6.3 for which the oxygen disorder is more pronounced.     

Characteristics optimization of activated alumina desiccants based on product of a centrifugal thermal activation of gibbsite

Activated alumina desiccants modified with NaOH and KOH were synthesized from the product of a centrifugal thermal activation of gibbsite, with the subsequent hydration in an acid or alkaline medium, and their properties were studied. It was shown that the modification makes it possible to raise the dynamic capacity of desiccants produced from pseudoboehmite by up to a factor of 2 via formation of new super-strong basic centers the concentration of which grows with increasing content of an alkaline oxide. A correlation was found between the total concentration of basic centers on the surface of the desiccants and their dynamic capacity in drying of both dry and humid air. Use of the modified desiccants with high static and dynamic capacity will make it possible to improve the drying efficiency.     

Synthesis,Structure, and Biological Activity of Products of Reactions of 3,4-Dioxohexane-1,6-dioic Acid Esters with 2-Aminophenol

Bioactive derivatives of 1,4-benzoxazine have been prepared via reactions of 3,4-dioxohexane-1,6- dioic (ketipic) acid esters with 2-aminophenol. (2'Z)-2,2'-(2-Hydroxy-2H-1,4-benzoxazin-2-yl-3-ilidene)diacetic acid esters or (2Z)-[2-oxo-2H-1,4-benzoxazin-3(4H)-ylidene]acetic acid esters can be formed depending on the conditions. The structures of the products of dialkyl ketipate esters reactions with 2-aminophenol were determined by means of X-ray diffraction. It has been demonstrated that the prepared compounds exhibit antimycotic activity against test cultures of plant pathogenic fungi (Fusauium sp., Alternarium sp., and Bipolaris soraciniana).     

Synthon-Based Approach to the Design of Macroheterocyclic Compounds Using Diaminothiadiazoles and Diamonotriazoles

Russian Journal of General Chemistry - Synthesis and properties of 2,5-diamino-1,3,4-thiadiazole, 3,5-diamino-1,2,4-thiadiazole, 3,5-diamino-1H-1,2,4-triazole,...     

The structure of a thiadiazole-containing expanded heteroazaporphyrinoid determined by gas electron diffraction and density functional theory calculations

The molecular structure of a macrocycle with a 24-membered ring, a thiadiazole-containing expanded heteroazaporphyrinoid, has been, for the first time, directly characterised by a synchronous gas electron diffraction and mass spectrometric experiment and DFT calculations; the molecule has the equilibrium structure of C(3h) symmetry with a planar macrocycle.