Vol 87, No 3 (2017)

Solid-state chemical reactions in the Bi₂O₃–SrO–TiO₂–Fe₂O₃ system have afforded layered perovskitetype oxides with the Aurivillius phases structure: (Bi_1–х,Sr_х)_m–1Bi2Fe_m–3Ti₃O_3m+3–δ (m = 4–7). Special features of their formation and thermal behavior have been studied.

The reactivity of 2,2-diphenyl-1,1,1-trichloroethane toward halide ions in dipolar aprotic solvents has been studied, and the mechanisms of its reactions with nitrite and halide ions have been compared. The results of kinetic and DFT quantum chemical studies suggest a common bimolecular elimination mechanism for both dehydrochlorination reactions.

Alkyl naphthalenecarboxylates and dialkyl naphthalenedicarboxylates have been synthesized by reactions of naphthalene and its derivatives with alcohols and carbon tetrachloride in the presence of iron catalysts.

Fusion 2-(4,6-dimethylpyrimidin-2-yl)-5-methyl-2Н-pyrazol-3-ol with phenols leads to the formation of complexes which exist due to a system of intermolecular N···H–O hydrogen bonds. The complexes are stable at high temperatures: their melting and subsequent thermolysis are accompanied by endothermic effects.

Physicochemical properties of 4,5-(aryl, alkyl)-3-substituted 2-sulfonylaminothiophenes have been studied. The effect of the nature of the substituents in the thiophene ring on acid-base properties, solubility, and chemical stability was investigated.

The data on stereoselective reactions of achiral compounds of trivalent phosphorus with chiral nucleophiles (derivatives of secondary alcohols, amines, and amino acids) are analyzed and discussed. In certain cases, these reactions enable preparation of optically active aminophosphines and phosphinites, precursors in the synthesis of chiral organophosphorus compounds and phosphine ligands. The reactions are suitable for elucidation of mechanism and stereochemistry of nucleophilic substitution at trivalent phosphorus atom.

By adding diethyl hydrogen phosphite to 5-trifluoromethyl-2-furaldehyde (5-trifluoromethylfur-2-yl)(diethoxyphosphoryl)methanol was synthesized. It was oxidized with DMSO-acetic anhydride mixture to diethyl 5-trifluoromethyl-2-furoyl phosphonate. The reaction of the latter with ethoxymethylenetriphenylphosphorane gives ethyl (2E)-3-(diethoxyphosphoryl)-3-(5-trifluoromethylfur-2-yl)propenoate. Analogous reaction of (diethoxyphosphoryl)(5-trifluoromethylfur-2-yl)acetic aldehyde yields ethyl (4E)-4-(diethoxyphosphoryl)-4-(5-trifluoromethylfur-2-yl)-but-3-enoate. The addition of nitromethane to these esters of unsaturated acids in the presence of potassium fluoride gives a mixture of diastereomers of phosphorylated esters of 2-nitromethyl-3-(5-trifluoromethylfur-2-yl)propanoic and 3-nitromethyl-4-(5-trifluoromethylfur-2-yl)butanoic acids respectively. By the reduction of ethyl nitropropanoate with zinc and formic acid in dioxane ethyl 2-aminomethyl-3-(diethoxyphosphoryl)-3-(5-trifluoromethylfur-2-yl)propanoate was prepared in a low yield. It may be considered as the derivative of β-alanine containing additional pharmacophore fragments.

Successive reactions of vanillin with aromatic aldehydes at the phenol group and ferroceneboronic acid at the carbonyl group catalyzed with various N-heterocyclic carbenes afforded the corresponding ferrocenyl esters. In these reactions copper(II) sulfate, cinnamic aldehyde, and air oxygen act as oxidants. The resulting ferrocenyl esters of vanillic acid were tested for cytotoxicity.

New porphyrazine bases containing peripheral benzyloxyphenyl groups have been synthesized by the template method. The procedure includes condensation of aromatic aldehydes with malononitrile, transformation of arylmethylidenemalononitriles to arylethenetricarbonitriles, template assembly of porphyrazine macrocycle on bis(indenyl)ytterbium(II) complex, and removal of the central metal ion. Luminescence properties of the synthesized porphyrazines and their dependence on the viscosity of the medium were studied, and the light and dark toxicities of the porphyrazines have been estimated. The obtained results suggest the possibility of using these porphyrazines as optical theranostic agents of new generation.

Energy profiles are calculated for the reaction of the structural isomer of N-vinylpyrrolidone with maleic anhydride in the gas phase. One of the reaction pathways leads to the formation and regeneration of maleic anhydride, acting as an activator of the process of (co)polymerization and dimerization of N-vinylpyrrolidone. According to calculations, the intermediate, isomer of N-vintlpyrrolidone, is a hybride of the singlet biradical and zwitter-ionic form.

The kinetic performance of strongly acidic sulfonate cation exchange resins towards ions of alkali metals (Li, K, and Na) under static conditions has been examined. Kinetic parameters of the sorption process, in particular, half-time of exchange and maximum possible flow rate of solution through the sorption column in the dynamic mode have been determined. The sorption kinetics mechanism has been explored. Recovery of the elements from model unicomponent solutions on strongly acidic cation exchange resins is satisfactorily described by pseudo-second-order kinetic model.

A series of novel 2-thioxoimidazolidine glycosides were prepared via reaction of the key intermediate 2-(benzylsulfanyl)-5-[4-(3-hydroxypropoxy)-3-(methoxybenzylidene)]-3-phenyl-1H-imidazol-4-one with different sugar aldose or sugar hydrazones to give the corresponding glycosides. The newly synthesized compounds were confirmed by physical and spectral data.

This report describes a new and convenient procedure for heterogenization of L-proline organocatalyst, which is based on non-covalent immobilization of L-proline on the surface of anion-exchange resin amberlite IRA900OH (AmbIRA900OH) as an efficient, cheap, and commercially accessible cationic polymer support. The ion-pair immobilization of L-proline on the surface of amberlite IRA900OH was achieved by treatment of a MeOH/H₂O solution of L-proline with amberlite IRA900OH at 60°C. L-Proline anion was exchanged with hydroxide ion and immobilized via ionic interaction between the carboxylate group of L-prolinate and quaternary ammonium cation of the cationic amberlite support. The prepared heterogeneous organocatalyst was characterized by FTIR, TGA, DTG, XRD, and elemental analysis techniques. The amberlitesupported catalyst was used as an efficient, reusable, and cheap catalyst for the one-pot three-component synthesis of 4H-pyrano[2,3-c]pyrazole derivatives in ethanol. The catalyst can be easily recovered and reused by simple filtration for several successive runs with no significant loss of catalytic activity.

A series of novel 1,3,4-oxadiazole fused pyridine derivatives were synthesized 11a–11f and their structures confirmed by IR, ¹H NMR and Mass spectral data. The compounds were evaluated for their antibacterial and antifungal activities against Gram negative and positive bacterial strains including Escherichia coli (MTCC 443), K. Pneumoniae (MTCC 109), S. Aureus (MTCC 96), B. Subtilis (MTCC 441) and Sclerotium rolfsii, Macrophomina phaseolina. Compounds 11d, 11e, and 11f demonstrated high antibacterial activity.

Frequently, in addition to X-ray and spectroscopic approaches, thermal analysis is the method of choice for comprehensive characterization of precipitated metal complexes. However, thermogravimetry itself is not sufficient enough for explaining complex decomposition or releasing steps. For correct elucidation of the decomposition mechanism of biomimetic Cd(II), Mn(II), and Zn(II) complexes with 1,1-diaminobutane–Schiff base, evolved gas analysis by mass spectrometry (EGA/MS) was used to define the thermally induced steps. Those were synthesized and characterized by hyphenated thermogravimetry-mass spectrometry (TG–MS) that allowed to interpret the decomposition steps.

A new approach to stereoselective synthesis of (4Z)-alkenoates has been developed based on Fecatalyzed cross-coupling of ethyl (4Z)-5-chloropent-4-enoate with the Grignard reagents.

The interaction of 2,3-dimethyl-4-oxo-1,3-benzoxazinium and 2-[β-(4-bromophenylvinyl)]-3-methyl-4-oxo-1,3-benzoxazinium perchlorates with hydrazine hydrate has afforded the corresponding triazoles that have been used as ligands for the synthesis of zinc complexes L₂Zn. Luminescent properties of the prepared complexes have been studied.

The influence of structural phase transitions, features of electronic structure, and magnetic transformation on the temperature dependence of the heat capacity of LnAO₄ (A = P, V, Nb) compounds has been considered. It has been shown that the sum of the contributions to the thermodynamic functions due to the phase transition can vary depending on the lanthanide ion. The contribution to the standard entropy caused by low-temperature phase transitions is the most significant.

Thermodynamic parameters of the inclusion complex formation of native and hydroxypropylated cyclodextrins with pharmacologically active niflumic and nicotinic acids were obtained and analyzed. It was shown that cyclodextrins selectively react with these acids and display a higher binding affinity to niflumic acid which is more hydrophobic and less hydrated compared to nicotinic acid. An influence of the cyclodextrin cavity size and accessibility of the hydroxypropyl substituent on the thermodynamics of the reactions and the binding mode of the acids was revealed and discussed in this work.

Nickel(II) bisnicotinamide sulfate was synthesized, isolated, and studied by means of FTIR spectroscopy, thermogravimetry, and differential scanning calorimetry with simultaneous mass-spectrometry analysis of pyrolysis products. The order the molecules are evolved from the coordination compound during thermal treatment is determined. The total heat effects of the processes involved in pyrolysis are estimated.

The paper focuses on the interaction of two heterocyclic amino acids and hydrophobic benzene with urea, dimethylformamide, and dimethylpropyleneurea in water at 298 and 313 K. The enthalpy and heat capacity parameters of the solute‒amide pair and triplet interactions have been computed via virial expansion technique. The results are discussed in terms of solvation effects in mixed solvents and their influence on the denaturation of globular proteins.

The results from application of calorimetric method for studying the energetics of the interparticle interaction in aqueous solutions of tetrapyridylporphyrin have been discussed. The influence of the nature of functional substitution, isomerism of the molecule on the enthalpies of dissolution and complexation with copper and zinc cations by tetrapyridylporphyrin derivatives has been elucidated. The thermal stability of crystalline samples of tetrapyridylporphyrin compounds under atmospheric oxygen conditions has been evaluated.

The protolytic equilibria in solutions of complexones, derivatives of ethylenediamine-N,N,N',N'-tetraacetic acid, were studied. The standard thermodynamic characteristics of step dissociation of these diamine complexones were calculated and interrelated with the structural features of these compounds.