Click chemistry methods are used to synthesize libraries of substances with high chemical diversity, which is important when developing new drugs. These reactions are necessary for introduction of labels (for example, fluorescent ones) into biological macromolecules, proteins, and DNA molecules. This is used in biological and medical research.
The most commonly used click chemistry reaction is the addition of a substance that contains a carbon-carbon triple bond (alkine) to a compound containing a fragment with three nitrogen atoms in a row (azide). The classic version of the reaction involves the use of copper in oxidation state (I) as a catalyst. For this, ions of copper (II) and an excess of a reducing agent are introduced into the reaction, or copper (I) is used and the reaction is conducted with protection against oxygen, which imposes certain restrictions on the application of this reaction.
A chemist from RUDN University Rafael Luque and his colleagues have developed a series of catalysts with copper ions attached to the surface of silica gel particles using cyclic cyclodextrin oligosaccharide. Cyclodextrin consists of seven glucose molecules closed in a cycle. Inside the cycle there is a container that can hold the copper ion and increase its catalytic activity. Ultrasound irradiation was used to facilitate the binding of cyclodextrin to the surface of silica gel.
The effectiveness of the created catalysts was evaluated on a model reaction of phenylacetylene with benzylazide. The researchers managed to achieve a yield of the reaction product of more than 99%. The yield with copper (II) acetate was 14%, and in the case of copper (II) sulfate, the reaction did not occur at all. The method for producing the catalyst is simple, safe for the environment, and cheap; its use does not require to add reducing agents or oxygen-free conditions. The catalysts can find application in the pharmaceutical industry and in biomedical research.
The paper was published in the journal Molecules.
A chemist from RUDN University has developed a catalyst for the production of eugenol acetate, a substance that destroys the larvae of mosquitoes transmitting dangerous diseases, being a safe chemical for human health.
RUDN soil scientists have revealed a direct correlation between the rate of soil formation of carbon dioxide, called CO2 emissions, and the content of microbial biomass in it. It is known that CO2 emission from soil is mainly conditioned by respiration of soil microorganisms and plant roots. The more CO2 soil emits, the more microbial biomass it usually contains. It was shown that CO2 emission by chernozem of different ecosystems (or different types of land use) correlates with the content of microbial biomass, and most closely with the rate of its microbial respiration. And the soil with good microbial properties has the “best quality”, is more fertile, provides the highest yield of crops and other plant biomass.
A RUDN chemist has synthesized a catalyst for the production of gamma-valerolactone — an energy-intensive “green” biofuel. The catalyst based on zirconium dioxide and zeolite has shown high efficiency in converting the waste of wood plant materials — methyl levulinate — to gamma-valerolactone.