Chemistry

Trifluoroacylation of Benzopirrolimidazolons under Various Conditions

The introduction of the (trifluoro)acetyl moiety into different heterocycles allows one to vary their physicochemical properties, change the nature and magnitude of biological activity, and also to carry out further chemical transformations. At the same time, modern methods of organic chemistry are aimed, inter alia, at increasing the efficiency of known and widely used chemical reactions and the possibility of directing along other paths when conducting syntheses under conditions, which are different from the classical ones.

Catalytic Conversion of Ethyl Alcohol on Zeolite Catalysts

This article describes the possibility of using bioethanol as a substitute for conventional fuel from petroleum feedstocks. Bioethanol obtained by fermentation from biomass is considered not only as an analogue of gasoline or a fuel additive, but also as a source of raw materials for the production of olefins, aromatic hydrocarbons and gasoline range hydrocarbons by means of catalytic conversion. At present, it is believed that the conversion of ethanol on zeolites proceeds in several stages.

Influence of Ascorbic Acid Isoforms on the Hydrodynamic Behavior of Chitosan Ascorbate Macromolecules in Aqueous Solution

The hydrodynamic behavior of chitosan macromolecules in aqueous solutions of ascorbic acid (AscA) diastereomers was studied by means of capillary viscometry. A comparison of these systems with chitosan solutions in such traditional solvent media as hydrochloric and acetic acids, Na-acetate buffer was made. Concentration dependencies of the specific viscosity were plotted, and the intrinsic viscosity and the Huggins constant were evaluated.

Test-Determination of Amoxicillin in Medications

Amoxicillin is a semi-synthetic aminopenicillin β-lactam series with a wide spectrum of antibacterial activity against many gram-positive and gram-negative microorganisms. It is included in the list of essential drugs. Test systems for the detection and identification of amoxicillin are missing. We have obtained indicator papers with immobilized ninhydrin and p-dimethylaminobenzaldehyde for the test determination of amoxicillin. The reaction conditions were selected, depending on the temperature and time. Color scales for visual colorimetric and colorimetric determination were constructed.

Transport Properties of Membranes on the Basis of Tetradecylammonium Associates with Complex Compounds Silver(I)-сefotaxime

Transport properties of the plasticized polyvinylchloride membranes on the basis of tetradecylammonium associates with complex connections silver (I) – cefotaxime in the conditions of a diffusive mass transfer and a direct current are investigated. With variation of concentration of electrode active substances (0.5; 1; 2; 3%), the external solutions contacting with membranes (10-2–10-7 M). It is established that resistance of membranes depends on the content of electrode active substances (EAS) and concentration of perimembrane solutions of a cefotaxime.

Interaction of Maleic Anhydride with 1,2-phenylenediamine under Different Conditions

The reaction of maleic anhydride with 1,2-phenylenediamine when heated in an aprotic solvent, regardless of temperature, proceeds with the initial formation of the primary addition product, namely, 4-[(2-aminophenyl)amino)-4-oxobut-2-enoic acid, which further undergoes heterocyclization within two ways, due to the presence of several electrophilic centers in the molecule, depending on the reaction conditions.

Synthesis and Ways of Formation of Hydroxyphenyl Substituted Triazolohexahydroquinazolines

With three-component condensation of 1,2,4-triazol-3-amine, hydroxy-substituted aromatic aldehyde (2-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 2-naphthalene-carbaldehyde), cyclohexanone, the aldehyde component has a defining impact on the shaping of triazologic hydroquinazolines with different types of rings articulation and the position of the double bond in them (C4a–C5 and C4a–C8a). When salicylic aldehyde is used, the positional isomers of the triazologic hexahydroquinazolines of angular and linear structure are formed in an equimolar ratio.

Exploration of Possibilities for Organic Selenides and Dihydroselenochromilium Salt Interaction with Diphenylpicrylhydrazyl

Higher fungi – basidiomycetes play significant role as food and biological subjects for establishing the regularities of the living systems’ operation, development and response to the different-nature effectors impact. Insufficient activity of the living organisms’ antioxidant system interfering the ability of overcoming the negative consequences of oxidative stress (excessive level of free radicals in cells) is believed to be a reason for the organisms aging and death.

Ionic Aggregation of Macromolecules as the Cause of the Kinetic (Non)Stability of Physicochemical Properties of Chitosan Solutions

Hydrodynamic, optical, colloid-flocculating, film-forming and structural morphological properties of diluted chitosan solutions (50–640 kDa) in acetate buffer (0.33 М СН3СООН + 0.2 М СН3СOONa), both initial ones and stored for ~1,850 days, were studied. It has been established that the decrease in the intrinsic viscosity of solutions over time is manifested for the reprecipitated and high-molecular-weight samples of chitosan to a greater degree. The viscosity drop effect is not affected by the use of untreated or sterile degassed distilled water to dissolve the polymer.

Rare Earth Metal Iminodisuccinates

Iminodisuccinates of several rare earth metals (REM) have been synthesized as a result of reaction between freshly prepared ammonia iminodisuccinate and REM chloride soltuions at pH 3. According to element analysis data, the chemical composition of synthesized salts is MeHC8H7O8N · nH2O, where Ме = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, n = 1–5. Synthesized compounds were further analyzed via X-ray diffraction and thermogravimetric analysis. According to X-ray data, REM iminodissucinates form well-defined crystals in two distinct isostructural groups.

Pages