Химия

Approaches to the design of new hybrid polyoxaheterocyclic compounds based on the interaction of 2-(4-carboxybenzylidene)-3,4- dihydronaphthalene-1(2H)-one with methylene active compounds of the 2H-chromen-2-one series – 3 -(1,3-dioxobutan-1-yl)-2H-chromen2-one and 4-hydroxy-2H-chromen-2-one, as well as their carbocyclic analogue – 1,3-indanedione under various conditions have been considered.

In this work, the interaction of diarylmethylidene piperidones with acetylacetone and acetoacetic ester has been studied. It has been shown that the transition to piperidone in the basis of dienone does not allow the selective synthesis of products. It has been found that the direction of the reaction with 1,3-C,C-dinucleophilic reagents is infl uenced by the nature of peripheral ylidene substituents, which allows targeted synthesis of O-heterocyclization products (hexahydropyranopyridines) by introducing an NO2 group into the arylmethylidene fragment.

One of the widely used antibiotics of the penicillin series in medicine are amoxicillin and amoxiclav – the representatives of "protected" penicillins. To control the concentration of these antibiotics, HPLC, spectrophotometry, capillary electrophoresis are applicable, which are long-lasting, require expensive equipment, operators and are not applicable for the express determination of aminopenicillins in biological and medicinal aqueous.

The structural and sorption properties of composite sorbents based on natural bentonite modified with carbon compounds have been investigated. Modification of the initial bentonite by low-temperature (650°C) pyrolysis of sucrose in the presence of metal salts of the iron subgroup leads to a significant increase in the specific surface area of composite sorbents (up to 275 m2/g), this is due to low-temperature catalytic graphitization of the carbon fraction formed during pyrolysis.

This work shows the possibility of synthesizing previously unknown 5-(4-bromophenyl)-3-((6-amino-2-mercaptopyrimidine)-4-amino)) methylidene-3H-furan-2-one containing a pharmacophore pyrimidine fragment by four-component one-pot reaction of malononitrile as the second methylene active component, thiourea, orthoester and 5-(4-bromophenyl)-3H-furan-2-one, which proceeds under mild conditions during thermal activation of the reaction mixture in isopropyl alcohol.

Исследована возможность включения кислотно-основных индикаторов (лакмуса, бромтимолового синего (БТС) и метилового красного (МК)) в структуры «ядро–оболочка», а также в микрокапсулы, сформированные методом полиионной сборки на основе ядер карбоната кальция и гидроксиапатита. Оценено влияние способа иммобилизации индикаторов (сорбция молекул на «ядрах», включение в полиэлектролитные (ПЭ) слои, инкапсулирование в полой ПЭ капсуле) и различных факторов на эффективность связывания.

The viscosity properties of diluted chitosan solutions in 2% and 70% acetic acid and sodium acetate buffer (1.9% CH3COOH + 1.6% СН3СООNа) within 25–70°C were studied. Concentra- tion dependences of the viscosity number were plotted. Intrinsic viscosities, Huggins’ constants and the temperature coefficients of viscosity were estimated. The intrinsic viscosity of solutions of this aminopolysaccharide in acetic acid has been found to be significantly higher than that in acetate buffer.

Показано, что охратоксин А образует в водных и мицеллярных растворах ПАВ с ионами европия (III) и тербия (III) комплексные соединения с переносом энергии, которые могут быть использованы в качестве аналитической формы для флуориметрического определения микотоксина.