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New stationary phases for hydrophilic chromatography (HILIC) with functional layers formed by the multicomponent Ugi reaction have been obtained. Acetone, glycolic acid, ethyl isocyanacetate, and 3‑aminopropyl silica, which also act as adsorbent matrices, were used as reaction components. The study of the effect of solvent on the reaction yield showed that a high degree of coverage of the matrix was achieved when the reaction was carried out in ethanol. The new adsorbents’ chromatographic properties compared with the initial matrix were assessed using the Tanaka tests for hydrophilic phases and by studying the retention of polar analytes from various classes. The synthesized adsorbents have demonstrated high efficiency and selectivity in separating model mixtures of sugars, amino acids, and water-soluble vitamins in the HILIC mode.

A new efficient method was proposed for the synthesis of (18-crown-6)stilbene; the structure of the product was confirmed by X-ray diffraction analysis. In MeCN, this compound forms pseudodimeric complexes with

Spectral, luminescent, and time-resolved properties of 2,4-dibenzylidenecyclobutanone and its diethylamino, methylthio, methoxy, and dimethoxy derivatives have been studied. The electron-donating substituents shift bathochromically the absorption band maximum by 45–140 nm relative to unsubstituted dienones and the fluorescence maximum by 50–125 nm relative to the methoxy derivative. Upon the laser pulse, dienones convert to the triplet state with a lifetime of 0.15–3.5 μs and a stable photoproduct is formed.

Spectral, luminescent, and time-resolved properties of 2-bezylidene-5-(pyridin-3-ylmethylene)cyclopentanone and its derivatives with electron-donating substituents (diethylamino, methoxy, methylthio, and dimethoxy) on the benzene cycle have been studied in acetonitrile at room temperature. The presence of substituents causes a long-wavelength shift of the absorption band maximum by 26–114 nm in comparison with the unsubstituted dienone and a long-wavelength shift of the fluorescence maximum by 43–125 nm in comparison with the methoxy derivative. Under laser irradiation of oxygen-free dienone solutions, intersystem crossing to the triplet state occurs with a half-life of 0.7–1.5 μs. A stable photoproduct is formed for the methoxy, methylthio, and dimethoxy derivatives of dienone.

Photoprocesses of bis(15-crown-5)-1,4-distyrylbenzene (DSB) and its complexes with barium and lead perchlorates in MeCN were studied by absorption, luminescence, and laser kinetic spectroscopies. Triplet DSB complexes are involved in the degradation of electronic excitation energy along with the trans—cis-isomerization and fluorescence processes. The most effective intersystem crossing was observed for the complex with lead perchlorate. The process is accompanied by a decrease in the quantum yield of DSB fluorescence and no trans—cis-isomerization is observed in this case. Shifts of spectral bands observed in the absorption and fluorescence spectra and the changes in the band intensities as well as the ability of DSB to form the 2: 2 bisandwich complex with barium perchlorate were explained using the results of quantum chemical calculations.

Photoprocesses in bis(18-crown-6)-1,4-distyrylbenzene (DSB) and its complexes with potassium, barium, and lead perchlorates have been studied in MeCN solutions by absorption, luminescent, and laser kinetic spectroscopy. The DSB molecules in the triplet state participate in the degradation of electron excitation energy, cis–trans isomerization, and fluorescence. The triplet–triplet absorption spectrum has several maximums in the range of 500–700 nm. The most efficient intersystem crossing to the triplet state is observed for the lead perchlorate complex, which is accompanied by a drop in the fluorescence quantum yield and the absence of trans–cis isomerization.

Spectral, luminescent, and kinetic properties of 2,5-bis(4-diethylaminobenzylidene)cyclopentanone (ketocyanine, A) in air-saturated and oxygen-free acetonitrile have been studied. The ns-Laser and continuous photoexcitation of A results in a product B undergoing in the oxygen-free solution the intersystem crossing into the triplet state with the lifetime of 1 µs. The photoinduced conversion of A into B occurs within a time shorter than 1 µs and is manifested in a decrease in both the fluorescence intensity of A and absorbance at 457 nm and in the appearance of a new absorption at λ > 535 nm. The product B undergoes photoinduced conversion to the parent A via both the excited singlet and triplet states of B.

Photonics of tetramethoxy-1,4-distyrylbenzene in MeCN was studied by absorption, luminescence, and laser kinetic spectroscopies. Photoinduced transformations of the compound in question involve cis–trans-isomerization, intersystem crossing, fast and delayed fluorescence, and electron transfer. The ground-state structure and vibrational spectrum, as well as the energies and structures of excited singlet and triplet states were calculated by the DFT/PBE and TDDFT/PBE0 methods. The assignment of vibronic bands in the absorption spectra was made and the energies of corresponding transitions were calculated.

The reaction of tetraethyl [1,3-phenylenedi(methylene)]bis(phosphonate) with formyl derivatives of benzocrown-ethers or formyl derivatives of o-dimethoxybenzene lead to high yield formation of the respectful bis(crown ether) containing 1,3-distyrylbenzenes or tetramethoxy-substituted 1,3-distyrenebenzenes. NMR spectra and quantum-chemical calculations showed the prevalence of unsymmetrical syn/anti,(syn,anti),syn/anti-conformations in 1,3-distyrylbenzenes. 1,3-Distyrylbenzenes absorb in shorter wavelength spectral region and have a weaker fluorescence than 1,4-distyrylbenzenes. The difficulty in the electrochemical reduction of 1,3-distyrylbenzenes comparing with 1,4-distyrylbenzenes is due to a less effective conjugation system in the metaderivatives.

Spectral, luminescent and time-resolved characteristics of 2,5-dibenzylidenecyclopentanone and its symmetrical derivatives (bis(N,N-diethylamino-), dimethoxy-, tetramethoxy-, dimethylthio-, and bis-18- crown-6 derivative) have been studied in media of different polarity (cyclohexane, toluene, acetonitrile, DMSO, and methanol) at room temperature. The absorption maximum of dibenzylidenecyclopentanone shifts bathochromically by 15 nm with an increase in polarity of the medium (cyclohexane–methanol). The introduction of electron-donating substituents in the aromatic rings of dibenzylidenecyclopentanone also results in a bathochromic shift of the absorption maximum by 100–130 nm in the media of different polarity and shifts the fluorescence maximum by 130 nm relative to the maximum of the dimethoxy derivative. Upon laser irradiation of oxygen-free solutions of dibenzylidenecyclopentanone and its tetramethoxy- and bis-18-crown-6 derivatives in acetonitrile, the triplet state with a half-life time of 0.3–1 μs is generated. For dimethoxy-, dimethylthio-, tetramethoxy-, and bis-18-crown-6 derivatives of dibenzylidenecyclopentanone, the isomers with a lifetime of ~50 ms are formed.

Photoprocesses in bis(15-crown-5)-1,3-distyrylbenzene (DSB) and its complexes with barium and lead perchloatewere studied in MeCN by absorption, luminescence, and laser kinetic spectroscopy. The triplet DSB molecules are involved in the degradation of electronic excitation energy, together with fluorescence processes. The most efficient intersystem crossing accompanied by a decrease in the DSB fluorescence quantum yield, occurs for the lead perchlorate complex. Using quantum chemistry methods (DFT and TDDFT), the geometry, structure, and transition energies to the S1 state were calculated for trans- and cis-isomers of DSB in the gas phase and with allowance for the solvent and for 1:1 and 2:2 DSB complexes with barium cation in the ground and excited states. The orbital structures of the 2:2 complexes were calculated by ab initio method, and conclusions were drawn about the possibility of [2 + 2]- photocycloaddition reaction.

Photoinduced processes in bis(diethylaminobenzylidene)cyclohexanone (CH1) and its bis(aza-18-crown-6) derivative (CH2) in acetonitrile at ambient temperature and 77 K have been studied. The absorption, fluorescence, and phosphorescence spectra of CH1 and CH2 are similar. The probability of the formation of the triplet state is higher for CH2 molecules (λT-Tmax = 660 nm, lifetime τT ~ 20 μs). The lifetime of the CH1 molecule in the triplet state is estimated at τT ~ 2–3 μs. Photoisomers of CH1 and CH2 are formed along with the triplet state. According to DFT calculation results, the formation of trans–cis photoisomers of CH1 and CH2 is the most energetically favorable.

An improved method for the synthesis of two symmetric biscrown-containing and one model tetramethoxy-substituted 1,4-distyrylbenzenes was suggested. The structures of compounds were established by 1H and 13C NMR spectroscopy and X-ray diffraction analysis. Spectrophotometric and fluorescent titration were used to determine spectral properties, stoichiometry, and stability of complexes of biscrown-containing 1,4-distyrylbenzenes with alkali and alkaline-earth metal cations. The stability of the complexes was found to depend on the metal cation size and charge, as well as on the size of the crown ether fragment. The electrochemical oxidation and reduction potentials of the biscrown-containing 1,4-distyrylbenzenes and the model compound in solution were determined and their basic differences from the corresponding characteristics of biscrown-containing stilbenes were identified.

A series of cross-conjugated dienones was synthesized to study the dependence of physicochemical characteristics on the nature of substituents in the aromatic groups of symmetric cyclopentanone dibenzylidene derivatives. The structure of compounds was established by electronic, IR, and NMR spectroscopy and X-ray diffraction study. All the compounds obtained possess the E,E-geometry. In the crystalline state, the arrangement of the dienone molecules is unfavorable for the intermolecular [2+2] photocycloaddition to take place. The low-temperature phases transition for unsubstituted diphenyl derivative of cyclopentanone was detected using variable-temperature X-ray diffraction and differential scanning calorimetry. Oxidation and reduction potentials of the dienones were measured by cyclic voltammetry. Their dependence on the nature and placement of substituents in the benzene rings was demonstrated. A linear correlation (R = 0.9343) between the difference of electrochemical oxidation and reduction potentials and the energy of the long-wavelength absorption maximum was found, that allows us to recommend the use of the data obtained in the correlation analysis of other compounds of this class.

The oxidation of 3,7-disubstituted hexahydroindazoles with potassium hexacyanoferrate(III) afforded previously unknown tetrahydro-2H-indazole derivatives. A novel ring contraction reaction leading to 2,3-diazaspiro[4.4]non-3-en-1-one derivatives was discovered. The product structure was proved by NMR spectroscopy, mass spectrometry, and X-ray analysis.

Photoprocesses of bis(18-crown-6)-1,3-distyrylbenzene (DSB) and its complexes with barium and lead perchlorates in a MeCN–CH2Cl2 (9:1, v/v) mixture were studied by absorption, luminescence, and laser kinetic spectroscopies. Unlike its strongly conjugated 1,4-isomer, 1,3-derivative shows almost independent behavior of its chromophoric subunits and is capable of phototransformations not observed in 1,4-distyrylbenzenes. Triplet DSB complexes are involved in the radiationless deactivation of the excited state along with the fluorescence processes. The most effective intersystem crossing was observed for the complex with lead perchlorate. The process is accompanied by a drastic decrease in the quantum yield of DSB fluorescence. Quantum chemistry (DFT and TDDFT) is used to calculate the geometric structure and absorption spectra of DSB and its complexes with barium and lead cations and to explain the observed results.

Spectral, luminescent, and time-resolved properties of 2,6-dibenzylidene cyclohexanone and its symmetric derivatives in the para-position of benzene ring (dimethoxy, dimethylthio, and bis-N,N-diethylamino groups) have been studied in media of different polarity (cyclohexane, acetonitrile, dimethylsulfoxide, and methanol). Introduction of electro-donating substituents to dibenzylidene cyclohexanone results in the red shift of the absorption maximum by 81–138 nm upon passing from the nonpolar to polar medium. Bis(N,N-diethylamino)dibenzylidene cyclohexanone fluoresces in polar solvents, acetonitrile, dimethylsulfoxide and methanol. The bathofluoric shift on passing from acetonitrile to methanol is 39 nm. The relative quantum yield of fluorescence in acetonitrile is seven times that in methanol. An intermediate species absorbing in the range of 400–560 nm with a maximum at 430–460 nm has been observed under the action of the laser pulse on dibenzylidene cyclohexanone solutions in acetonitrile. The intermediate species has a lifetime of 40, 20, and 7 μs for dibenzylidene cyclohexanone and its dimethylthio and dimethoxy derivatives, respectively.

Dienones (ketocyanine dyes) containing two aza-18-crown-6 ether residues were synthesized. The complex formation of these dyes with the EtNH3+ and +H3N(CH2)nNH3+ ions (n = 2–10, 12) in MeCN was studied by electronic and 1H NMR spectroscopy, including spectrophotometric and 1H NMR titration. It was found that homoditopic bis-azacrown dienones and alkanediammonium ions with a short polymethylene chain form 1:1, 2:2, and 1:2 complexes, whereas alkanediammonium ions with a long polymethylene chain form only pseudocyclic 1:1 complexes. The stability constants of the resulting complexes were determined (logK1:1 varies in the range from 2.74 to 5.62 [M–1], logK2:2 = 2.1 [M–1], and logK1:2 varies in the range from 2.03 to 2.96 [M–1]). The most stable complexes are formed by diammonium ions with a long polymethylene chain owing to simultaneous binding of both NH3+ groups to the azacrown ether residues of the dye. The structure of supramolecular complexes was confirmed by quantum chemical calculations.

The acylation of unsymmetrical N-benzylbispidinols in aromatic solvents without an external base led to the formation of supramolecular gels, which possess different thicknesses and degrees of stability depending on the substituents in para-positions of the benzylic group as well as on the nature of the acylating agent and of the solvent used. Structural features of the native gels as well as of their dried forms were studied by complementary techniques including Fourier-transform infrared (FTIR) and attenuated total reflection (ATR) spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and small-angle X-ray scattering and diffraction (SAXS). Structures of the key crystalline compounds were established by X-ray diffraction. An analysis of the obtained data allowed speculation on the crucial structural and condition factors that governed the gel formation. The most important factors were as follows: (i) absence of base, either external or internal, (ii) presence of HCl, (iii) presence of carbonyl and hydroxyl groups to allow hydrogen bonding, and (iv) presence of two (hetero)aromatic rings at both sides of the molecule. The hydrogen bonding involving amide carbonyl, hydroxyl at position 9, and, very probably, ammonium N-H+ and Cl&minus, anion appears to be responsible for the formation of infinite molecular chains required for the first step of gel formation. Subsequent lateral cooperation of molecular chains into fibers occurred, presumably, due to the aromatic &pi, &minus, &pi, stacking interactions. Supercritical carbon dioxide drying of the organogels gave rise to aerogels with morphologies different from that of air-dried samples.

The acylation of unsymmetrical N-benzylbispidinols in aromatic solvents without an external base led to the formation of supramolecular gels, which possess different thicknesses and degrees of stability depending on the substituents in para-positions of the benzylic group as well as on the nature of the acylating agent and of the solvent used. Structural features of the native gels as well as of their dried forms were studied by complementary techniques including Fourier-transform infrared (FTIR) and attenuated total reflection (ATR) spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and small-angle X-ray scattering and diffraction (SAXS). Structures of the key crystalline compounds were established by X-ray diffraction. An analysis of the obtained data allowed speculation on the crucial structural and condition factors that governed the gel formation. The most important factors were as follows: (i) absence of base, either external or internal; (ii) presence of HCl; (iii) presence of carbonyl and hydroxyl groups to allow hydrogen bonding; and (iv) presence of two (hetero)aromatic rings at both sides of the molecule. The hydrogen bonding involving amide carbonyl, hydroxyl at position 9, and, very probably, ammonium N-H+ and Cl− anion appears to be responsible for the formation of infinite molecular chains required for the first step of gel formation. Subsequent lateral cooperation of molecular chains into fibers occurred, presumably, due to the aromatic π−π-stacking interactions. Supercritical carbon dioxide drying of the organogels gave rise to aerogels with morphologies different from that of air-dried samples.

Photoprocesses in bis(diethylaminobenzylidene)cyclopentanone (D1) and its bis(aza-18-crown-6) derivative (D2) have been studied in acetonitrile. The absorption, fluorescence, and phosphorescence spectra of D1 are similar to those of D2. Laser excitation of oxygen-free solutions of D1 and D2 leads to generation of a triplet state with a lifetime of ∼1 μs and two intermediate species with lifetimes of ∼100 μs and longer than 1 s.

The challenges of the modern society and the growing demand of high-technology sectors of industrial production bring about a new phase in the development of organic synthesis. A cutting edge of modern synthetic methods is introduction of functional groups and more complex structural units into organic molecules with unprecedented control over the course of chemical transformation. Analysis of the state-of-the-art achievements in selective organic synthesis indicates the appearance of a new trend — the synthesis of organic molecules, biologically active compounds, pharmaceutical substances and smart materials with absolute selectivity. Most advanced approaches to organic synthesis anticipated in the near future can be defined as 'atomic precision' in chemical reactions. The present review considers selective methods of organic synthesis suitable for transformation of complex functionalized molecules under mild conditions. Selected key trends in the modern organic synthesis are considered including the preparation of organofluorine compounds, catalytic cross-coupling and oxidative cross-coupling reactions, atom-economic addition reactions, methathesis processes, oxidation and reduction reactions, synthesis of heterocyclic compounds, design of new homogeneous and heterogeneous catalytic systems, application of photocatalysis, scaling up synthetic procedures to industrial level and development of new approaches to investigation of mechanisms of catalytic reactions. The bibliography includes 840 references.

The paper presents the synthesis of a series of adamantyl phosphate esters. Five compounds (oxo and hydroxy substituted adamantyl phosphates) were tested for their inhibitory activity with respect to myo-inositol monophosphatase.

Four (2R,3S)-N-benzoylphenylisoserine esters with substituted bicyclo[3.3.1]nonanes are synthesized. The compounds are found to be unable to promote tubulin polymerization, but cause a weak tubulin aggregation (oligomerization).

2-(endo-7-Hydroxybicyclo[3.3.1]non-exo-3-ylmethyl)propane-1,3-diol was synthesized in seven steps starting from endo-7-hydroxybicyclo[3.3.1]nonane-exo-3-carboxylic acid. The title compound attracts interest as intermediate product for the synthesis of potential tubulin ligands.

The reactions of 5-acylpyrimidine-4-thiones with aliphatic diamines in the presence of NiII and CoII salts were studied. New NiII and CoIII complexes with ligands of the pyrimidinethione series were synthesized. The results of the reactions of 5-acetyl-6-methyl-2-phenylpyrimidine-4-thione and 5-acetyl-2,6-dimethylpyrimidine-4-thione with ethylenediamine or 1,3-diaminopropane in the presence of NiCl2· 6H2O or CoCl2·6H2O depend on (1) the nature of the substituent at position 2 of the pyrimidine ring, (2) the length of the polymethylene bridge between the nitrogen atoms in the diamine molecule, (3) the nature of complex-forming metal, and (4) the pyrimidinethione: diamine ratio. The resulting complexes were studied by electrochemical methods. The mechanism of electrooxidation and electro-reduction of 5-acylpyrimidine-2-thiones and related nickel and cobalt complexes was proposed. The structures of the complexes were investigated by NMR, UV-Vis spectroscopy, and IR spectroscopy and mass spectrometry. The molecular structure of fac-tris(5-acetyl-2,4-dimethylpyrimidine-6-thiolato)cobalt(III) was established by X-ray diffraction. According to semiempirical quantum-chemical calculations by the PM3(tm) method, both the highest occupied and lowest unoccupied molecular orbitals in the molecules of the compounds under study have a π symmetry and are localized predominantly on the ligand fragments.

Published data on the synthesis of azoles containing two pyridine substituents are analyzed in relation to the type of central five-membered ring. The applications of such molecules as ligands in coordination chemistry are discussed.

A tritylated product of 3-hydroxymethylbicyclo[3.3.1]nonan-2-on-7-ol ethylene acetal cyclization, 4-hydroxymethyl-3-[2-(trityloxy)-ethoxy]-2-oxatricyclo[4.3.1.03,8]decane, was found to have a crystal structure comprising close packed molecular layers intersected by infinite tubes filled with solvent molecules.

The synthesis and the results of biological testing of novel N-benzoylphenylisoserine-modified L-lupinine and L-menthol are reported.

A preparation is reported of some previously unknown 1,4-disubstituted adamantane derivatives containing a phenylisoserine fragment.

The synthesis of the title bicyclononane colchicine analogues by Diels—Alder reactions of appropriate dienophiles with dienes proves to be rather difficult.

Aldol condensation of acetylpyridines with aromatic aldehydes was studied. A series of new products of cascade reactions were isolated and characterized.

Novel exo-bidentate ligands containing two γ-pyridyl fragments and their complexes with silver(i) tetrafluoroborate were synthesized.

A new supramolecular synthon, a 2L: 1M complex of bidentate bispidine with transition metal, was suggested. A number of complex compounds of 1,5-dimethylbispidin-9-one with Cu ii , Ni ii , and Co ii salts (perchlorates, chlorides, bromides, nitrates, trifluoroacetates) were synthesized. The structure and composition of complexes obtained were estimated based on the combination of physicochemical methods of analysis (elemental analysis, X-ray diffraction analysis, NMR, IR, and Raman spectroscopy, electron absorption spectroscopy, ESI mass spectrometry, CVA). The composition of most complexes in the solid state corresponds to the formula ML2X2, and in a number of cases the fragment [ML2]2+ is retained in solution, which was shown by NMR spectroscopy for nickel complexes and by mass spectrometry for copper complexes. In the case of copper chloride, the composition of the acetonitrile solutions in the presence of the ligand depends on the ratio of starting compounds and their concentration: an increase in proportion of CuCl2 and concentration shifts the equilibrium to the side of complexes with higher nuclearity. A 2L: 1M complex of bispidine with metal was for the first time structurally characterized using copper(ii) nitrate derivative as an example. The CVA method showed existence of reversible electrochemical reduction of the metal for a number of complexes (the products of the reaction of 1,5-dimethylbispidin-9-one with nickel(ii) and cobalt(ii) chlorides, as well as with nickel(ii) bromide). According to the IR and Raman spectra, chelation of metals with 1,5-dimethylbispidin-9-one leads to the shift of the absorption band of the ligand carbonyl group from 1700 to 1721–1744 cm−1. Nickel(ii) and copper(ii) perchlorates and nitrates were concluded to be the most promising complexation agents for the binding of two NH,NH-bispidine ligands in a coordination polymer.