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A convenient procedure has been developed for the synthesis of 3β,28-diacetoxylup-20(29)-en-30-oic acid via oxidation of 3β,28-di-O-acetylbetulin with selenium dioxide in aqueous ethanol on heating, followed by oxidation of 3β,28-diacetoxylup-20(29)-en-30-al thus formed with sodium chlorite in tert-butyl alcohol. The alkylation of 3β,28-diacetoxylup-20(29)-en-30-oic acid with 1,3-dibrompropane and 1,5-dibromopentane in boiling acetonitrile in the presence of potassium carbonate afforded the corresponding ω-bromoalkyl esters in high yields.

A water-soluble thiacalix[4]arene derivative containing four diethylenetriamine fragments in 1,3-alternate stereoisomeric form has been obtained for the first time. Using ethidium bromide, it has been found that the macrocycle can interact with calf thymus DNA. The macrocycle has been found to interact with DNA via groove binding. The presence of four diethylenetriamine fragments on the calixarene platform leads to multivalent interactions with DNA, resulting in an increase in the binding constant by two orders of magnitude compared to individual diethylenetriamine.

A procedure for the chloromethylation of lipophilic distally di-O-substituted calix[4]arene derivatives has been developed to prepare dichloromethyl derivatives of calix[4]arenes with long-chain alkyl fragments in cone configuration in high yields. From the chloromethylated derivatives, ammonium/imidazolium salts containing azidopropyl moieties have been synthesized in high yields. The structure of all obtained compounds has been established by 1D and 2D NMR, IR spectroscopy, and MALDI spectrometry. They can be further used as precursors of polytriazole/polyimidazole polymer species as promising carriers for metal-complex catalysis.

The attack of the thiol sulfur atom (P–SMe) on the methine carbon as the main route of the new reaction of dichloromethylarenes with S-methyl diethylthiophosphinate has been predicted and experimentally confirmed on the basis of the electronic structure of the S-alkyl esters of P(IV) acids. The processes of the mono- and di(dechloromethylthioylation) of dichloromethyl group have been realized. A new approach to the synthesis of the arenecarbaldehyde dimethyl dithioacetals has been developed avoiding the use of gaseous highly toxic methyl mercaptan.

A new strategy of synthesis of thiacalix[4]monothiacrown ethers in 1,3-alternate stereoisomeric form has been suggested and implemented through macrocyclization of the lower rim of 3-bromopropoxy-substituted thiacalixarenes by dithiols.

Amphiphilic calixarene derivatives with different lipophilicities and containing four 4,5-dicarboxytriazolyl fragments on the upper rim in a cone stereoisomeric form are obtained via azide-alkyne addition reaction. We showed that the amphiphilic macrocycles substituted with four octyl and tetradecyl groups on the lower rim form the monodisperse nanoaggregates in aqueous solutions. We found that the macrocycles possess fluorescence in the blue region. When concentration increases, there is a bathofloric shift of the emission maximum, which is due to aggregates. The resulting macrocycles were successfully used as a micellar medium for the Suzuki coupling reaction to show quantitative yields of iodine and bromoarenes in aqueous medium at room temperature.

A copper-palladium catalyst supported on amino-modified silica has been synthesized by chemical reduction. It has been found that submicron particles of a copper-palladium alloy are formed on the silica surface. Unlike commercially available palladium catalysts (Pd/Al2O3, Pd/C, Pd/BaSO4), the synthesized copper-palladium catalyst makes it possible to selectively reduce the nitro group in 3-nitrobenzaldehyde and 1-chloro-4-nitrobenzene.

Aromatic azido derivatives of p-tert-butylcalix[4]arene have been obtained for the first time using copper-catalyzed nucleophilic aromatic substitution of azide anion for bromide in 5,11,17,23-tetrabromo- 25,26,27,28-tetrabuthoxycalix[4]arene in a dioxane–water (3: 1) solvent mixture with N,N-dimethylethylenediamine as a stabilizing ligand for copper(I). When the reaction is carried out under with microwave heating, partial substitution products (mono-, distally di-, proximally di-, and trisubstituted) can be isolated in satisfactory yields.

Trends of cesium-137 and americium-241 extraction from carbonate–alkaline media with p-tert-butylcalix[n]arenes with macrocycles of different size (n = 4, 6, 8), including monofunctional derivatives with lipophilic substituents for increasing their solubility in organic media, were studied. It was demonstrated that O-n-octyl ethers of p-tert-butylcalix[6]arene appeared to be the most efficient extractants for Cs(I) cations, while it was p-tert-butylthiacalix[4]arene for and americium(III) cations.

This review is devoted to the scientific achievements of the departments of organic chemistry in higher schools of Russia within the past decade.

An approach to molecular nanotubes of a new type based on bisthiacalix[4]arene with ethylene sulfide bridges in cone stereoisomeric form has been suggested and implemented. This ligand has shown selective liquid-phase extraction of Ag+.

Successive functionalization of p-tert-butylcalix[4]arene afforded a bifunctional derivative containing photopolymerizable pentacosa-10,12-diynoic acid fragments on the upper rim and propargyl groups on the lower rim of the macrocycle having a cone structure. The functionalization can be readily accomplished via copper-catalyzed azide–alkyne cycloaddition under mild conditions.

The review describes the history of development of organic chemistry in higher schools of Russia over a period of 170 years, since the emergence of organic chemistry in our country till now.

MALDI mass spectrometry is used for the first time for the rapid assessment of the binding of thiacalix[4]arene-monocrown-ethers with metal cations (Li, Na, K, Cs, Cu, Ag). The work is performed on examples of thiacalix[4]arene-monocrown-ethers in 1,3-alternate conformation with various numbers (m) of ethylene oxide units and various substituents in phenol groups. It is shown that thiacalix[4]arene-monocrown- ethers with m = 3, 4, 5, and 6 bind lithium, sodium, potassium, and cesium cations, respectively; in addition, the binding of cesium cations is stronger in the presence of aromatic substituents in the lower rim of thiacalix[4]arene-monocrown-ethers. Silver cations bind with calixarenes under study more intensely than copper ions. When aromatic substituents are present, the binding of silver cations is stronger than that of alkali metal ions with the studied thiacalix[4]arene-monocrown-ethers.

Previously unknown isononylcalix[8]arene was synthesized from commercially available isononylphenol. The properties of the product (solubility, extraction ability, tendency to aggregation) were compared with those of the known tert-butylcalix[8]arene. The extraction of 137Cs, 99m Tc, and 241Am from alkaline carbonate solutions with solutions of p-alkylcalix[8]arenes (alkyl = tert-butyl, isononyl) in tetrachloroethylene was studied. The dependence of the distribution ratios on pH of the aqueous phase in the interval from 11 to 13.9 and on the nature of functional groups in the calixarene core was determined. The composition of extractable solvates of cesium and americium with calix[8]arenes was found. Calix[8]arenes extract cesium from alkaline solutions more efficiently than p-tert-butylphenol, their nonmacrocyclic analog, does. tert-Butylcalix[8]arene exhibits the highest performance, which may be due to formation of aggregates 5.7 ± 0.8 nm in diameter in the organic phase at pH 13.5 of the aqueous phase. The isononyl derivative exists in the monomeric form (particle diameter 1.9 ± 0.5 nm).

Surface modification of the luminescent silica nanoparticles doped with Tb(III)–p-sulfonatothiacalix[ 4]arene complex was carried out using a series of nitrogen/oxygen-containing trialkoxysilanes. It was found that groups capable of nonspecific interactions on the surface of the nanoparticles cause a significant decrease in their colloidal stability. The chromophore moieties in the modifiers were found to quench the luminescence of the nanoparticles. The surface modification of the nanoparticles is responsible for the change in the mechanism of luminescence quenching in the presence of copper(II) ions due to decreased accessibility of luminophores to the quencher.

A new method of synthesis of functionally substituted benzaldehydes by catalytic debromometoxylation of dibromomethylarenes with benzaldehyde dimethyl acetal has been suggested. Anhydrous zinc chloride has been used as a catalyst. Being soft Lewis acid, it formed no strong complex with aldehyde group and other functional groups. The initial acetal has been readily recovered by the treatment of benzaldehyde isolated from the reaction mixture with trimethyl orthoformate.

Lower-rim substituted bis- and tetrakis(alkynyloxy)thiacalix[4]arenes in cone and 1,3-alternate configurations were synthesized by the Mitsunobu reaction, and their structure was determined using homoand heteronuclear one- and two-dimensional NMR techniques. Bis(prop-2-yn-1-yloxy)thiacalix[4]arene was found to exist in conformational equilibrium whose position depends on the temperature and reaction conditions.

First 1,3-alternate p-tert-butylthiacalix[4]arenes containing N-acylamide fragments have been synthesized by reaction of thiacalix[4]arene carboxylic acid chlorides with 2-substituted 4,5-dihydro-1,3-oxazoles, and their aggregation properties have been studied.

This paper reports a predictive model for the rate constant of the bimolecular nucleophilic substitution involving the azide moiety. It predicts reaction rate constants in different solvents, including organic mixtures, and with different organic and inorganic azides as reactants. The optimal descriptors describing solvent effects and a cation type in the azide salt were suggested. A reasonably good predictive performance of the model in cross-validation has been demonstrated. The model was applied to predict the rates of the reactions between sodium azide with two conformers of calixarenes as well as 3-bromopropyl phenyl ester. For sterically non-hindered molecules, a good agreement between predicted and experimental reaction rates was observed. On the other hand, the model poorly reproduces the results for sterically hindered molecules.

The aggregation of amphiphilic oxyethylated calix[4]arene is studied in the absence and presence of polyethyleneimine. At low calixarene concentrations, large ensembles with a hydrodynamic diameter of about 100 nm are formed and coexist with small (smaller than 10 nm) aggregates, which are observed in the entire concentration range. It is established that calixarene-based systems catalyze the neutral hydrolysis of bis(chloromethyl)phosphinic acid p-nitrophenyl ester, with the catalytic effect being as high as two orders of magnitude in the presence of La(III) ions. The rate of hydrolysis of phosphonates depends on the composition of the supramolecular system. The maximum acceleration exceeds three orders of magnitude in comparison with alkaline hydrolysis of the substrates.

The rate of carboxylic ester cleavage by amphiphilic low-molecular-weight and polymeric amines in the presence of polyoxyethylated calix[4]arenes with different degrees of oxyethylation is determined by the formation of mixed aggregates, by the shift of pK a of the amine, and the character of the distribution of the reactants in functional micelles. All of the systems show a high substrate specificity. In the case of octyl- and decylamines, the reaction of p-nitrophenyl acetate is catalyzed and the reaction of more hydrophobic p-nitrophenyl laurate is inhibited. An opposite situation is observed in the systems based on branched polyethyleneimine: the reaction of p-nitrophenyl acetate is inhibited and the process involving p-nitrophenyl laurate is accelerated.

170 Nowadays, one of the intensively developed areas in organic chemistry focuses on design, synthesis, and studying the properties of nanoscale molecular sys tems containing several structural blocks capable of fulfilling different functions, for example, receptor and sensor functions. Such molecules can serve the basis for design of “smart” materials in various areas of nanoengineering and materials science. The most effi cient strategy of obtaining such nanosystems involves combination of appropriate structural fragments. In particular, combination of a calixarene and crown ether moieties in one molecule led to the appearance of a new class of receptors, calix crown ethers 1a, which exhibit extremely high alkali metal ion bind ing selectivities [1–9]. Polyether bridged calix[4]arenes 1b [1, 2] exhibit a high Cs+/Na+ selectivity (more than 30 000) in solution. They are widely used as iono phores and carriers in liquid membranes [3, 4]. However, no attempts to fix them onto a solid sub strate for creating ion selective electrodes and sen sors have been described so far, since no efficient ways of synthesis have been developed for calix crown ethers in which the acyclic substituent R contains functional groups capable of fixing the molecule onto a solid surface and forming regularly arranged nanolayers and films. In this context, it is of definite interest to introduce thiol groups into such structures, since they can be efficiently fixed on the gold and silver surface [10]. CHEMISTRY

The methods of cyclic voltammetry, electrolysis, and spectrophotometry were used to study electrochemical properties of (TCAS + Fe3+ + dipy), (CCAS + Fe3+ + dipy), and (CCAS + Fe3+ + [Co(dipy)3]3+) triple systems (where TCAS is n-sulfonatothiacalix[4]arene, CCAS is tetracarboxylate n-sulfonatocalix[4]arene, and dipy = α,α′-dipyridyl) in an aqueous solution. One-electron reduction of Fe(III) in the (TCAS + Fe3+ + dipy) system at pH 2.5 results in electroswitching of iron ions from the lower TCAS ring to the upper ([Fe(dipy)3]2+). Reverse electrochemical switching of the system is impossible due to mediator ([Fe(dipy)3]2+/3+) oxidation of TCAS. Reverse electroswitching of Fe(III) ions from unbound to bound state as ([Fe(dipy)3]2+) with CCAS has been revealed in the system (CCAS + Fe3+ + dipy) (pH 1.7) upon single-electron transfer, whereas reversible electroswitching by the upper rim of CCAS from one complex ion ([Co(dipy)3]3+) to another ([Fe(dipy)3]2+) has been demonstrated in the system ([Co(dipy)3]3+ + CCAS + Fe3+ upon double-electron transfer. In all systems, electric switching was accompanied by synchronous color switching.

The magnetic properties of new bifunctional molecular magnets based on nitrosyl complexes of ruthenium and thiacalix[4]arenes of rare-earth ions (Gd3+, Dy3+) have been investigated. A photoinduced decrease in the magnetization of the molecular magnet with rare-earth ions Gd3+ and the absence of a photomagnetic effect in crystals with rare-earth ions Dy3+ have been revealed at a temperature of 2 K. It has been found that, in the sample containing Dy3+ ions, the magnetization deviates by 6% from the calculated value for noninteracting ions. A comparison of the results obtained for two groups of isostructural samples, which differ only in the type of rare-earth ions, has demonstrated that the observed deviation of the magnetization is caused by the interaction of the orbital moment of the Dy3+ ions with the crystal field.

Structures of 5,11,17,23-tetra-tert-butyl-25,26,27-trihydroxy-28- and 5,11,17,23-tetra-tert-butyl-25,26-dihydroxy-27,28-[N-(4′-nitrophenyl)aminocarbonylmethoxy]thiacalix[4]arenes (I, II) (solutions in CDCl3) were studied by 1H and 13C 1D and 2D (NOESY) NMR spectroscopy combined with the use of computational simulation (semiempirical quantum-chemical calculations, method PM3). Compound I was found to exists in the cone conformation, and the bulky substituent OCH2C(O)NHPhNO2, in contrast to the crystalline state, was located in the exo position to the macrocycle cavity; for compound II the cone conformation was observed, where the substituents are turned to the inside of the cavity of the macrocycle (endo position).

The structure of three isomers of 5,11,17,23-tetra-t-butyl-25,26,27,28-tetrakis[(morpholidocarbonyl) methoxy]-2,8,14,20-tetrathiacalix[4]arene in conformations of partial cone, 1,3-alternant and cone was studied by the methods of 1D and 2D (NOESY) 1H and 13C NMR spectroscopy in conjunction with computational modeling (semiempirical quantum-chemical PM3 calculations). Characteristic cross-peaks for each conformer in the two-dimensional NOESY spectra were established. It is found that unsymmetrical conformation of partial cone is more “flattened” as compared with highly symmetrical 1,3-alternant and cone conformations, while OCH2C(O)NC4H8O substituent is located in the exo-position. Theoretical modeling is found to be more consistent with the experimental data for highly symmetrical conformations.

The extraction of gadolinium(III) and lanthanum(III) ions at the cloud point is studied in Triton X100 micellar solutions in a wide range of pH. In the absence of chelating agents, lanthanum(III) and gadolinium(III) ions are unselectively extracted at pH > 6. It is shown that the use of p-sulfonatothiacalyx[6(8)]arenes as chelating agents noticeably enhances the degree of extraction at pH 2–6. The composition and stability of lanthanum-p-sulfonatothiacalyx[n]arene complexes (n = 4, 6, 8) are estimated in a wide range of pH by pH-potentiometry. The degree of Gd3+ and La3+ ions extraction, which is performed at the cloud points employing calyxarene macrocycles of different sizes, is depended on the acidity of a medium.

According to X ray crystallographic analysis of compounds 1 and 2, both molecules have a chair con formation with the equatorial tert butyl substituent. Comparison of the geometric analysis of the rings of 1,3,2 dioxaphosphepines, phosphorinanes [2], and seven membered tert butylphosphonates with oxirane and thiirane planar fragments [3] indicates that the equatorial tert Bu group has no effect on the internal geometry of the ring. However, the lack of the “fro zen” NMR spectra of compounds 1 and 2 prevented us from drawing firm conclusions about their confor mations in solutions. In this context, of considerable interest is studying the effect of the tert butyl group on the geometry and conformations of the dioxaphosphepine ring, as well as analysis of experimental NMR data with the use of quantum chemical calculations. Quantum chemical calculations were performed by the hybrid B3PW91 density functional theory method [4, 5] with the use of the 6 31G(d) basis set. In all cases, all geometrical parameters of the molecules were optimized. The cor respondence of the found structures to PES minima was proved by all positive Hessian values. The chemi cal shifts and spin–spin coupling constants (SSCCs) were calculated by the GIAO method [6]. Calculations were performed with the Gaussian 09 program package at the Joint Supercomputer Center, Kazan Branch, Russian Academy of Sciences (http://wt.knc.ru).

A comparative study of the texture and adsorption characteristics of newly synthesized composite materials based on 1,4-benzenedicarboxylate metal-organic framework MOF-5 and calix[4]arenes with various structures was performed.