Reaction of dibromoalkanes with silyl phosphites. Synthesis and properties of mono-and diphosphonoalkanes

Reactions of dibromoethane and dibromopropane with silyl phosphites are studied. Mono-and diphosphonoalkanes of various structures were prepared, and their chemical properties were studied.     

Solvophobically Driven Complexation of Adamantyl Mannoside with β-Cyclodextrin in Water and Structured Organic Solvents

The effects of solvent and temperature on the complexation of adamantyl mannoside with β-cyclodextrin and 6-O-monotosyl-6-deoxy-β-cyclodextrin were explored experimentally and by means of molecular dynamics simulations. Efficient binding was observed only in hydrogen-bonded solvents, which indicated solvophobically driven complexation. The stability of the inclusion complex was considerably higher in aqueous media. A pronounced temperature dependence of Δ_rH^○ and Δ_rS^○, resulting in perfect enthalpy–entropy compensation, was observed in water. The complexation thermodynamics was in line with classical rationale for the hydrophobic effect at lower temperatures and the nonclassical explanation at higher temperatures. This finding linked cyclodextrin complexation thermodynamics with insights regarding the effect of temperature on the hydration water structure. The complexation enthalpies and entropies were weakly dependent on temperature in organic media. The signs of Δ_rH^○ and Δ_rS^○ were in accordance with the nonclassical hydrophobic (solvophobic) effect. The structures of the optimized product corresponded to those deduced spectroscopically, and the calculated and experimentally obtained values of Δ_rG^○ were in very good agreement. This investigation clearly demonstrated that solvophobically driven formation of cyclodextrin complexes could be anticipated in structured solvents in general. However, unlike in water, adamantane and the host cavity behaved solely as structure breakers in the organic media explored so far.     

2-[(Diallyl)hydroxymethyl]pyrrolidine in radical (co)polymerization reactions

The feasibility of the free-radical (co)polymerization of 2-[(diallyl)hydroxymethyl]pyrrolidine is studied. It is found that, under radical-initiation conditions, this monomer is not involved in homopolymerization and copolymerization with vinyl monomers; however, it exhibits high activity during copolymerization with sulfur dioxide. Copolymerization proceeds to yield alternating copolymers of an equimolar composition. The main polymer chain contains both linear fragments formed via opening of one double bond of 2-[(diallyl)hydroxymethyl]pyrrolidine and cyclolinear structures resulting from the participation of two double bonds in the reaction. It is demonstrated that the copolymers obtained are optically active.     

Study of nitrogen- and sulfur-containing heterocycles. 54. Properties and conversions of pyrimido[4,5-<Emphasis Type="Italic">b</Emphasis>]-1,4-benzothiazepines. Synthesis of a novel heterocyclic system: Pyrimido[5,4-<Emphasis Type="Italic">c</Emphasis>]isoquinoline

We have studied some properties and conversions of pyrimido[4,5-b]-1,4-benzothiazepines: reduction, oxidation, reactions with nucleophilic reagents (methanol, hydrazine, hydroxylamine, o-methylhydroxylamine, and thiosemicarbazide). We have synthesized derivatives of a novel heterocyclic system: pyrimido[5,4-c]isoquinoline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1863–1872, December, 2004.For Communication 53, see [1].     

Synthesis of 2-quinolinecarboxamide derivatives as potential HDAC inhibitors

Inhibition of histone deacetylase activity appears as an original and effective approach for the treatment of cancer. A series of novel quinoline-containing derivatives has been synthesized and found that some of these compounds possess nanomolar histone deacetylase inhibitory activity.     

Electrically Conductive Composites Based on Chitosan and Graphene Stabilized by Pluronic F-108

Highly concentrated dispersions of few-layer graphene stabilized by amphiphilic block copolymer Pluronic F-108 are obtained. According to transmission electron and atomic force microscopy, the thickness of the graphene particles is on average from one to ten layers and their lateral sizes vary from 150 nm to 1 μm. Using these dispersions, new chitosan-based film composites with the filler content up to 5 wt % are obtained; the electrical conductivity of these composites reaches 4.3 × 10^–1 S/cm.     

Electrosurface characteristics of bulk titanium dioxide in solutions of simple electrolytes. III. Effect of multiply charged cations on adsorption and electrokinetic parameters of TiO<Subscript>2</Subscript>

The electrosurface characteristics of titanium oxide nanoparticles synthesized by the sol-gel method are studied in relation to the pH and concentration of solutions of sodium, potassium, barium, and lanthanum chlorides. The surface charges and electrokinetic potentials are found, and the positions of the points of zero charge are analyzed as depending on the type and concentration of cations. The absence of a negative region of the electrokinetic potential, which results from the superequivalent adsorption in the Stern layer, is revealed for BaCl₂ and LaCl₃ solutions.     

(Mg,Ni)Ga2O4 Solid Solution with a Spinel Structure

Doklady Chemistry - The boundaries of Mg1&nbsp;–&nbsp;xNixGa2O4 solid solutions (0 ≤ х ≤ 0.5) with a spinel structure synthesized by the gel combustion method,...     

Methods for the detection of sulfur mustard metabolites in biological materials: An analytical review

This review surveys published data to generalize methods for the determination of sulfur mustard and its metabolites in various media. Attention is focused on biological materials. Data on the toxicokinetics and metabolism of sulfur mustard are cited, and the problem of choosing a biomarker for the indication of sulfur mustard poisoning is considered.