Reduction of 4-nitrostyrene to 4-aminostyrene

Reduction of 4-nitrostyrene with Fe⁰, Fe²⁺, and S₂O ₄ ^2? was studied. A new method of 4-aminostyrene synthesis was developed.     

Synthetic transformations of isoquinoline alkaloids. 1-alkynyl-3,6-dimethoxy-N-methyl-4,5α-epoxy-6,18-endoethenobenzo[i]isomorphinans and their transformations

The reaction of thebaine with 2-bromo-6-methyl-1,4-benzoquinone regioselectively afforded 6,18-endo-etheno-9-methyldihydrothebainehydroquinone. Iodination of 6,18-endo-ethenodihydrothebainehydroquinones with N-iodosuccinimide in trifluoroacetic acid was also selective, and the corresponding 1-iodo derivatives were formed. The main reaction pathway in the halogenation of 6,18-endo-ethenodihydrothebainehydroquinone with iodine chloride was chlorination of the fused hydroquinone fragment. The Sonogashira reaction of 1-iodo-6,18-endo-ethenodihydrothebainehydroquinones with trimethylsilylacetylene and subsequent desilylation gave 1-ethynyl-6,18-endo-ethenodihydrothebainehydroquinones. 1-[3-(4-R-Piperazin-1-yl)-propynyl]- and 1-{3-[2-(pyridin-3-yl)piperidin-1-yl]propynyl}-6,18-endo-ethenodihydrothebainehydroquinones were synthesized by the Mannich reaction of acetylenic derivatives of dihydrothebainehydroquinone with piperazine and anabasine in the presence of formaldehyde, catalyzed by copper(I) compounds. The reaction of 1-iodo-6,18-endo-ethenodihydrothebainehydroquinone with N-methylpiperazine and formaldehyde was accompanied by copper-catalyzed oxidative homocoupling.     

Specific features of rubber recovery from a latex with N,N-dimethyl-N,N-diallylammonium chloride under the action of magnetic field

The influence of the magnetic field intensity and treatment time on the efficiency of coagulation of SKS-30 ARK butadiene-styrene latex in the presence of a cationic electrolyte, N,N-dimethyl-N,N-diallylammonium chloride, was examined.     

Preparation of poly(vinylidene fluoride) nanocomposite membranes based on graft polymerization and sol–gel process for polymer electrolyte membrane fuel cells

Proton conducting nanocomposite membranes consisting of poly(vinylidene fluoride-co-chlorotrifluoroethylene)-graft-poly(styrene sulfonic acid), i.e., P(VDF-co-CTFE)-g-PSSA graft copolymer and sulfonated silica and were prepared using a sol–gel reaction and subsequent oxidation of a silica precursor, i.e., (3-mercaptopropyl) trimethoxysilane (MPTMS). The successful formation of amorphous phase nanocomposite membranes was confirmed via FT-IR and wide-angle X-ray scattering. All membranes were semi-transparent and mechanically strong, as characterized by a universal tensile machine. Transmission electron microscopy and small-angle X-ray scattering analysis revealed that silica 5–10 nm in size were homogeneously dispersed in the matrix at up to 5 wt.% of MPTMS. At higher concentrations, the silica grew to more than 50 nm in size, which disrupted the microphase-separated structure of the graft copolymer. As a result, both proton conductivity (0.12 S/cm at 25 °C) and single cell performance (1.0 W/cm² at 75 °C) were maximal at 5 wt.% MPTMS.     

Synthetic transformations of sesquiterpene lactones. V.* Synthesis and cytotoxicity of 13-aryl-substituted tourneforin derivatives

13-Aryl-substituted tourneforin derivatives were synthesized via the Heck reaction with aryliodides. The structure of (E)-13-(3,4-dimethoxybenzyl)-eudesma-4(5),11(13)-dien-6α,12-olide was confirmed by an XSA. A study of the cytotoxicity of the synthesized derivatives for CEM-13, MT-4, and U-937 tumor models showed promise for the modification.     

Synthesis,structure, and luminescent properties of lanthanide coordination compounds with 3-methyl-4-formyl-1-phenylpyrazol-5-one

An exchange reaction of the sodium salt of 3-methyl-1-phenyl-4-formylpyrazol-5-one (HL) with chlorides or nitrates of lanthanides (Ln = La, Nd, Sm, Eu, Gd, Tb, Dy, and Yb) was used to synthesize coordination compounds of composition LnL₃·nSolv (Solv = H₂O or EtOH). According to powder X-ray diffraction data, these compounds constitute two series: one comprises lanthanum and neodymium complexes, and the other, samarium, europium, gadolinium, terbium, dysprosium, and ytterbium complexes. For the complexes of the first series, the structure was solved in a single-crystal diffraction experiment carried out on [La₂(μ-L)₃(L)₃(H₂O)₃]·2MeOH. The lanthanum atoms in the complex are at a distance of 4.222(2) — from each other, and they are structurally nonequivalent and linked by three 5-hydroxy-4-formylpyrazole anions. Solid-phase samples of the coordination compounds under study feature weak luminescence in the spectral regions intrinsic to lanthanide cations.     

Conversion of isopropyl alcohol to acetone in fullerite cavities

Fullerite with cavities containing dichlorobenzene (DCB) and isopropyl alcohol (IPA) molecules was prepared by the addition of IPA to a solution of fullerene C₆₀ in DCB. On heating in vacuo fullerite evolves IPA, and the temperature increase to 200—350 °C results in the evolution of acetone. No products of DCB conversion were observed. Possible products of the interaction of 60 with two IPA molecules were calculated by the quantum chemical method. New data on the fullerite structure were obtained by transmission electron microscopy X-ray powder diffractometry, mass spectrometry, IR spectroscopy, and other methods. One of the possible mechanisms of the reaction IPA → acetone was considered.     

Effect of synthesis conditions on molecular characteristics of acrylamide copolymers with acrylic acid,carriers of cationic biologically active substances

Methods of molecular hydrodynamics and optics were used to study properties of aqueous solutions of acrylamide copolymers with acrylic acid. Dependences of the molecular characteristics of the copolymers on their synthesis conditions were determined and conditions were found in which the process of radical copolymerization of acrylamide with acrylic acid yields water-soluble carboxyl-containing acrylamide copolymers with molecular masses not exceeding 4×10⁴ Da.     

Diels-alder reactions with cyclic sulfones: VIII. Organic catalysis in the synthesis of spiro[1-benzothiophene-4,5′-pyrimidine]-2′,4′,6′-trione 1,1-dioxides and 2′-thioxospiro[1-benzothiophene-4,5′-pyrimidine]-4′,6′-dione 1,1-dioxides

5-Isopropenyl-2,3-dihydrothiophene 1,1-dioxide reacted with 5-methylidenepyrimidine-2,4,6-triones and 5-methylidene-2-thioxopyrimidine-4,6-diones in the presence of chiral amines or amino acids with high regio- and stereoselectivity to give optically active derivatives of barbituric and thiobarbituric acids spirofused at the 5-position to 1-benzothiophene 1,1-dioxide fragment. The reaction of 5-isopropenyl-2,3-dihydrothiophene 1,1-dioxide with 5-(2-methoxybenzylidene)-2-thioxopyrimidine-4,6-dione (generated in situ from 2-methoxybenzaldehyde and thiobarbituric acid) in the presence of (?)-ephedrine or L-4-(tert-butyldimethylsiloxy) proline gave the corresponding 2-thioxospiro[1-benzothiophene-4,5′-pyrimidine]-4′,6′-dione 1,1-dioxide with an enantiomeric excess of 80%.     

Some results of the growth of semiconductor crystals in microgravity conditions (to the 50th anniversary of Yuri Gagarin’s flight into space)

The history of the growth of semiconductor crystals aboard space vehicles and their subsequent investigation has been described shortly. It has been shown using Ge(Ga), GaSb(Si), and GaSb(Te) crystals as an example that the formation of segregation growth striations can be avoided during their recrystallization by the vertical Bridgman method in conditions of physical simulation of microgravity on the Earth, mainly due to the essential weakening of the thermal gravitation convection. By their structure and impurity distribution, they approach the crystals grown in space. The investigation of recrystallization of Te has made it possible to determine the role of the detachment effect characteristic of the microgravity conditions and the features of the microstructure of the samples that crystallize with a free surface. The analysis of the results obtained from experiments in space allows us to better understand the processes occurring during the crystallization of the melts and to improve the crystal growth in terrestrial conditions.