3

The purpose of this work is to investigate the thermodynamic properties of the solubility of methyl 6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydro-pyrimidine-5-carboxylate, which exhibits a wide spectrum of biological activity in organic solvents of different polarity and their character of mixing. As you know, the processes of synthesis and purification of solid substances, allmost, occur with the help of individual solvents or their mixture, so optimization of these processes is impossible without determining the thermodynamic parameters of their dissolution.

A green synthetic route for eco-safe and solvent-free preparation of biologically active 3,4-dihydropyrimidin-2-(1H)-ones/thiones derivatives via one-pot, three-component Biginelli condensation reaction of β-keto esters (methyl or ethyl acetoacetate), aromatic aldehyde (benzaldehyde derivatives) and urea or thiourea have been developed using a salicylic acid as a bio-based, natural and versatile catalyst.

The synthesis of new hybrids 1,3,4-oxadiazol-2-thione with acridine 9(10H)-one is carried out. Their structure is confirmed by LC-MS, IR-, 1H and 13C NMR-spectroscopy. The thione-thiol equilibrium was investigated in eight solvents with different relative permittivity with the help of UV-spectroscopy and quantum chemistry methods using DFT/B3LYP and HF bases. The results of the experimental calculations are in agreement with theoretical ones and have shown the prevalence of the thione.

The reaction of azo-bis-cyanuric chloride as strong electrophilic aza-dienophile in Diels-Alder cycloaddition with a number of dienes of different nucleophilicity, namely 2,3-dimethylbutadiene, 2-methylbutadiene and 1-acethoxybutadiene, was carried out and computationally analyzed on B3LYP/6-31G(d,p) level. Local and global reactivity indices, based on FMO theory, as well as TS geometries and activation energies were calculated. Reaction proceeds rapidly with high yields and in mild conditions. Ways of products further modification by chlorine atoms substitution were also studied.

Cyanuric chloride is a valuable starting agent for the direct obtaining of highly structured molecules. The substitution of chlorine atoms in the molecule of cyanuric chloride by various pharmacophores’ fragments provides the obtaining a number of 1,3,5-triazine derivatives, among which the promising biologically active substances showing antimicrobial, anticancer, antimalarial and antiviral activity were detected.

The Diels-Alder reaction is widely used in organic synthesis, since it allows using a variety of dienes and dienophiles to obatin six-membered cycles in one step. Azo compounds, especially with electron deficient substituents, such as the 1,3,5-triazine ring, can interact as active dienophiles in the Diels-Alder reactions.

The derivatives of 6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid are the simplest representatives of Bidzhenelli’s dyhidropirymidynes and are characterized by a wide range of biological activity. It is important to use pure substances at each stage of the synthesis in the pharmaceutical industry. The main method of solid substances purifying is recrystallization using the so-called "classic" solvents, which include acetonitrile.

В результаті взаємодії азо-біс-ціанурхлориду зі стиролом був виділений один з ізомерів інвертованої реакції Дільса-Альдера з високим виходом. Для пояснення селективності реакції були проведені термодинамічні розрахунки на M06-2X/6-31G(d,p) рівні. Протікання реакції досліджувалось по трьох шляхах – з утворенням продукту нормальної ДА та двох регіоізомерів інвертованої ДА реакції.

За температурною залежністю розчинності метилового естеру 6-метил-2-оксо-4-арил-1,2,3,4-тетрагідропіримідин-5-карбонової кислоти в ізопропанолі, етилацетаті та бензолі розраховано ентальпію та ентропію його розчинення. З врахуванням ентальпії плавлення, визначеної за даними диференційно-термічного аналізу та перерахованої на 298К, розраховано ентальпії та ентропії змішування за 298 К. Показано вплив розчинника на розчинність та величини ентальпії і ентропії змішування при 298К.

The joint process of isobutylene oxidation and butene-1 oxidative dehydration is studied on the basis of Fe-Te-Mo-Ox catalyst in the impulse flown plant. The optimal process conditions of products yield (methacrolein, butadiene-1,3) are determined. It is shown that the selectivity by butadiene-1,3 increases with the contact time rising at 633 K and the selectivity by methacrolein at 693 K is maximal at contact time of 0.6 s. The maximal total yield of the target reaction products (68.7 %) is obtained at 693 K and contact time of 3.6 s.