Synthesis of heteroannular mercury derivatives of acetoxy- and methoxyferrocene

Conclusions The synthesis of 1,1-(acetoxy)chloromercuryferrocene, di-1(1-acetoxyferrocenyl)mercury, 1,1-(methoxy)chloromercuryferrocene, and di-1-(1-methoxyferrocenyl)mercury from ferrocenylboric acids was described.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2574–2575, November, 1967.     

Caste and Population Specificity of Termite Cuticule Hydrocarbons

The composition of hydrocarbons from the termites Reticulitermes lucifugus Rossi and Kalotermes flavicollis Fabr. belonging to different castes and populations was determined using GC and mass spectrometry. The role of cuticular hydrocarbons in olfactory recognition of termite caste and population status was demonstrated.__________Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 3–6, January–February, 2005.     

Dynamic equations for time-averaged coordinates at thermal equilibrium

The Hamilton variational principle with coarse variation (over a limited number of parameters introduced into the coordinates) is used to find relations for the time-averages of defined functions of the coordinates and velocities. The dynamic equations for the parameters characterizing the average behavior of the coordinates are then found by orthogonalization of the coordinates. It is shown that the entropy of the dynamic system is expressed in terms of these averaged parameters, and the dynamic equations and stability conditions may be found by minimization of the defined function of the motion, which is constructed like the thermodynamic potential. A perturbation procedure is suggested for solving the dynamic equations.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 87–94, April, 1991.     

4-Hydroxylindole-acetic acid — The microbiological transformation product of indole-3-acetic acid

Conclusions The isolation of an unknown intermediary in the microbiological transformation of indole-3-acetic acid to 4-hydroxyindole-3-acetic acid may help us to determine the structure of 4-hydroxyindole-3-acetic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1155–1158, May, 1975.The authors express their gratitude to G. K. Skryabin and M. N. Kolosov for assistance in carrying out the present work.     

Arginine-hydrolyzing enzymes for electrochemical biosensors

Since l-Arginine (Arg) is a semi-essential amino acid for humans, its adequate amount must be consumed in the diet to prevent certain negative consequences related to insufficient synthesis of this amino acid under specific physiological conditions. Arg metabolism results in the production of a biochemically diverse range of such products as urea, some amino acids, creatine, polyamines, nitric oxide, etc. Arg, an important biomarker in clinical diagnostics, is also used for prevention/treatment of different diseases, including cancer and COVID-19. Furthermore, it serves as an indicator of food and beverages quality.A variety of optic and electrochemical methods for Arg determination have already been suggested. The biosensor systems based on the enzymes of Arg metabolism were shown to be the most promising tools for Arg assay. This review focuses on the peculiarities of electrochemical biosensors for Arg assay based on the use of Arg-degrading enzymes and on the analysis of their advantages as compared to other approaches.     

Synthesis of new-type 1,3,6-triazocine via intramolecular reactions of iodocyclization and [3+2] azido cycloaddition

Selective iodocyclization of 6-(alkenylamino)-1-allylpyrazolo[3,4-d]pyrimidines provided hydrogenated derivatives of 1-allyl-8(9)-iodomethylimidazo(pyrimido)[1,2-a]pyrazolo[4,3-e]pyrimidines which were further reacted with NaN₃ at 75°С to 80°С to give a series of new-type 1,3,6-triazocines annulated with the pyrazole, pyrimidine, imidazole (or pyrimidine), and 1,2,3-triazole rings. The compounds synthesized were structurally characterized by analytical, spectral (IR, ¹H and ¹³C NMR, HPLC-mass), and X-ray diffraction data.     

Mixed-ligand complexation of iron(III) ethylenediaminetetraacetate with iminodiacetate and ethylenediamine in aqueous solution

The formation of the heteroleptic complexes FeEdtaIda³⁻ and FeEdtaEn⁻(Ida²⁻ is the iminodiacetate anion and En is ethylenediamine) was examined by direct calorimetry, pH potentiometry, and spectrophotometry at 298.15 K and the ionic strength I = 0.5 (KNO₃). A possible way of coordination of the ligands in the heteroleptic complexes was discussed.     

A three-atomic model of crystals with supercritical behavior

In the three-atomic Frenkel model, the intermediate atom is placed in the middle between the two end atoms, where a potential energy minimum is localized for small lengths of the straight-line segment; the intermediate atom is shifted from the midpoint where a potential energy maximum arises toward one of the end atoms as the segment length increases. In the model length-temperature phase diagram, a region of the first-order phase transitions terminated by a critical point lying on the length axis is observed. In the present paper, the three-atomic model with dissimilar end atoms is considered. In this case (for example, in the absence of attraction to one of the end atoms), the potential energy can have only one minimum, and the first-order transitions are absent. According to dynamic theory, the calculated behavior of the middle atom that depends on the temperature for the constant length demonstrates the phenomenon of supercritical transition connected, according to V. K. Semenchenko, with a passage of the stability determinant through a minimum without stability loss. If the force applied to the end atoms is set rather then the model length, equations are solved for the displacement of atoms, rms oscillation amplitude, and deformation by means of expansion in a series in the anharmonicity coefficients, and the result obtained demonstrates a linear temperature dependence of the coefficient of elasticity. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 16–26, March, 2007.