Multicomponent reactions are modern methods of obtaining biologically active compounds. An example of such a reaction is the well-known pyrimidine ring construction reaction - the Biginelli reaction. Biginelli reaction products attract the attention of researchers as a class of organic substances with a broad spectrum of biological activity and as highly effective key compounds for modifying existing active biological matrices. According to the literature, so far, among the substances of this class, substances with anti-viral, anti-fungal activities have been discovered. The general and topic-specific objectives are: to develop methods for the synthesis of substituted dihydropyrimidine-5-carboxylates and their use to obtain biologically active polifunctional organic compounds. Performing the synthesis of substituted dihydropyrimidine-5-carboxylates in the presence of biodegradable and renewable catalysts. Given a considerable practical interest in these heterocyclic compounds, it should be noted that in this reaction the obtaining of "eutectic solvents" based on native components (tartaric acid, choline chloride, dihydroabytic acid, urea, etc.) and the research of the catalytic properties of "eutectic solvents" ”In order to obtain substituted dihydropyrimidine-5-carboxylates is very important. In recent years, the direction of green solvents, called "eutectic solvents", has been investigated. The first efforts of the chemists were directed towards the development of green solvents. There is a class of natural eutectic solvents, which have liquid supermolecules, consisting of natural primary metabolites (ex. organic acids, carbohydrates, alcohols, amines and amino acids) linked together by intermolecular interactions, especially hydrogen bonds. They are used in the fields of human health, in the manufacture of pharmaceuticals and food. They are also used in various metabolic extraction processes, in enzymatic reactions. Natural eutectic solvents occur in almost all organisms. They are found around membranes, cells and are involved in the biosynthesis, solubilization and storage of various poorly soluble metabolites in water and unstable compounds in cells. At the same time, the new concept of "green chemistry" has emerged, which promotes the production of chemicals that are free of toxicity to humans and the environment and the use of renewable and biodegradable organic raw materials. Ionic liquids, a class of green solvents, have found applications in various fields of human activity, due to their specific physicochemical properties. But some studies have shown the negative side of ionic liquids, such as toxicity, low biodegradability, high cost. Ionic liquids can be used in biocatalysis, offering many advantages compared to the same reactions performed with organic solvents, which are widely used.