Conjugates of polyhedral boron compounds with carbohydrates 6. Synthesis of glycoconjugates of closo-ortho-carborane with β-lactosylamine and β-d-galactopyranosylamine derivatives as galectin bi- and trivalent ligands

Five glycoconjugates were obtained from ortho-carboranylacetic acid and β-actosylamine or β-d-galactopyranosylamine derivatives with the terminal amino group in the spacer. The glycoconjugates have different lengths of the spacer (9 to 15 atoms) and contain two or three βlactosylamine residues or one, two, or three β-d-galactopyranosylamine residues.     

Kinetics and mechanism of nickel reaction with benzyl bromide in dimethylformamide

Abstarct  The reaction of nickel with benzyl bromide in DMF has been studied. The reaction intermediates were investigated by different methods and the kinetic and thermodynamic parameters were determined. The reaction of benzyl bromide with nickel was shown to occur on the metal surface by the Langmuir-Hinshelwood scheme, with the formation of benzyl radicals which are recombined and isomerized in solution to form 1,2-diphenylethane and trace amounts of 4.4′-dimethylbiphenyl. Original Russian Text ? A.M. Egorov, S.A. Matyukhova, I.S. Kocherova, A.A. Novikova, A.V. Anisimov, 2009, published in Zhurnal Obshchei Khimii, 2009, Vol. 79, No. 3, pp. 455–463.     

Structure of KTiOAsO<Subscript>4</Subscript> single crystals at 293 and 30 K

The unit cell parameters of KTiOPO₄ and KTiOAsO₄ single crystals are measured in the temperature range from room temperature to 20 K. It is found that the unit cell volume of the single crystals changes smoothly. With a decrease in temperature, the c parameter remains almost unchanged. In a certain temperature range, the linear temperature dependence of the a and b parameters is violated. An X-ray diffraction study of KTiOAsO₄ single crystals is performed at T = 293 and 30 K. With a decrease in temperature, the electron density in the channels of the structure undergoes a redistribution, suggesting that at room temperature the state of the potassium ions is characterized by the dynamic and static disordering. The nonuniformity of the distribution of the electron density at the junctions of TiO₆ octahedra and AsO₄ tetrahedra is significantly enhanced in relation to that at the corresponding junctions in the KTiOPO₄ structure. It has been experimentally established that the geometry of the tetrahedral anions makes a decisive contribution to the nonlinearity of KTiOAsO₄ single crystals.     

Adducts of Diethyldithiocarbamate Complexes of Zinc(II) and Copper(II) with Piperidine [M(Pip)(Edtc)2] and Their Solvated Forms [M(Pip)(Edtc)2] · L (L = C6H6, C5H5N,C4H9NO): Synthesis,EPR and Solid-State (13C, 15N) CP/MAS NMR Studies

Crystal adducts of diethyldithiocarbamate complexes of zinc(II) and copper(II) with piperidine (Pip) were synthesized, and their solvated forms with the outer-sphere molecules of benzene, pyridine (Py), and morpholine (Mf) were obtained. Adducts with composition [M(Pip)(Edtc)₂] · L (L = Py, Mf) were shown to be able, in principle, to give solvated isomers [M(L)(Edtc)₂] · Pip with the Pip molecule arranged in the outer sphere. The composition, structure, and properties of the obtained adducts were studied by EPR, high-resolution solid-state ¹³C, ¹⁵N NMR spectroscopy. Solvation of all three adducts with Pip, Mf, and Py was found to result in a substantial increase in the contribution of the trigonal–bipyramidal component to the geometry of a copper coordination pentahedron. In addition, for adducts with Mf and Py, a structural unification of two isomeric forms was observed at the molecular level to yield a qualitatively new (rather than intermediate) state. It was shown that in all solvated forms of the copper(II) adducts, the metal polyhedron is mainly a trigonal bipyramid, while the square–pyramidal contribution is insignificant. Results of (¹³C, ¹⁵N) NMR studies revealed a structural inequivalence of the Edtc^–ligands in the zinc adducts under investigation.     

The Design,Synthesis, and Biological Activities of Pyrrole-Based Carboxamides: The Novel Tubulin Inhibitors Targeting the Colchicine-Binding Site

Microtubule targeting agents (MTAs) that interfere with the dynamic state of the mitotic spindle are well-known and effective chemotherapeutic agents. These agents interrupt the microtubule network via polymerization or depolymerization, halting the cell cycle progression and leading to apoptosis. We report two novel pyrrole-based carboxamides (CAs) (CA-61 and -84) as the compounds exhibiting potent anti-cancer properties against a broad spectrum of epithelial cancer cell lines, including breast, lung, and prostate cancer. The anti-cancer activity of CAs is due to their ability to interfere with the microtubules network and inhibit tubulin polymerization. Molecular docking demonstrated an efficient binding between these ligands and the colchicine-binding site on the tubulin. CA-61 formed two hydrogen bond interactions with THR 179 (B) and THR 353 (B), whereas two hydrogen bonds with LYS 254 (B) and 1 with ASN 101 (A) were identified for CA-84. The binding energy for CA-84 and CA-61 was −9.910 kcal/mol and −9.390 kcal/mol. A tubulin polymerization assay revealed a strong inhibition of tubulin polymerization induced by CA-61 and -84. The immunofluorescence data revealed the disruption of the tubulin assembly in CA-treated cancer cells. As an outcome of the tubulin inhibition, these compounds halted the cell cycle progression in the G2/M phase, leading to the accumulation of the mitotic cells, and further induced apoptosis. Lastly, the in vivo study indicated that CAs significantly inhibited the HCC1806 breast cancer xenograft tumor growth in a nude mouse model. Collectively, we identified the novel CAs as potent MTAs, inhibiting tubulin polymerization via binding to the colchicine-binding site, disrupting the microtubule network, and exhibiting potent pro-apoptotic activities against the epithelial cancer cell lines both in vitro and in vivo.     

Perovskite-like modification of Cs3Sb2I9 as a member of theOD family A3B2X9

The structure of the trigonal modification of Cs₃Sb₂I₉was refined by XRD methods (Syntex {ie572-1} diffractometer, λMoK_α at T = 285 K. The structure is ofperovskite type A₃B_3-xX₉ with ordered vacancies in the B-sublattice. The unit cell with pseudo-R-centering has the following parameters: α = 8.435(7), c = 10.390(7) Å, V = 757.5 ų, Z = 1; d_x = 4.67 g/cm₃. The centrosymmetric space group {ie572-2} was chosen based on the laser radiation second harmonic generation test. The parameters of the pseudo-rhombohedron corresponding to the perovskite cell are a’ = 5.976 å, α = 89.78°. The R-lattice of a perovskite structure is disturbed by ordered Sb vacancies in one of the three I₆, octahedra. The structural modifications of the compounds A₃B₂X₉ are analyzed in terms of Dornberger-Schiffs OD theory as the members of the family formed by the two-dimensional periodic fragments ofperovskite type structures.     

Synthesis of Substituted N‐Formylaminomethylenediphosphonates and Their Derivatives

The convenient methods for the synthesis of new trimethylsilyl esters of aminomethylenediphosphonic acids are elaborated. The new substituted N‐formylaminomethylenediphosphonates are obtained via the interaction of trimethylsilyl esters of methylenediphosphonic acids with a mixture of triethyl orthoformate and ethanol. Also boron trifluoride–diethyl etherate as an effective catalyst is used for the interaction of hydrochlorides of ethoxymethylene imines with diethyl trimethylsilyl phosphite. The corresponding aminomethylenediphosphonic acids are presented.     

Synthesis of new functionalized aryl‐substituted methylphosphonic and methylenediphosphonic acids and their derivatives

The convenient syntheses of new aryl‐substituted hydroxymethylphosphonic and methylenediphosphonic acids from the aromatic aldehydes, their derivatives, and phosphorous acid esters in the presence of the effective catalysts (trimethylsilyl trifluoromethanesulfonate, zinc chloride, and cadmium iodide) were developed.