Synthesis of phenyl analog of retinoic acid methyl ester proceeding from 3-(bromomethyl)but-3-enal diethylacetal

Aromatic analog of retinoic acid methyl ester was prepared using a convenient prenylating agent, 3-(bromomethyl)but-3-enal diethylacetal, and Barbier reaction in the key stage of building up the carbon chain of target molecules. A version is offered of the synthesis of methylidene analog of aromatic retinoic acid.     

New asymmetric synthesis of a pheromone component of the shield bug Cantao Parentum

A novel procedure has been developed for the synthesis of (2S,4R,6R,8S)-2,4,8-trimethyl-1,7-dioxaspiro[5.5]undecane, a pheromone component of the shield bug Cantao Parentum, through intermediate cyclopropanol derivatives in the key stages of carbon chain construction and introduction of functional groups.     

EPR studies on the di-nitrogen centers with nonequivalent atoms in a reddish-brown plastically deformed diamond

Two new di-nitrogen centers, which were labeled M2 and M3, were found together with known W7 and N4 centers in an unusual reddish-brown natural diamond. The following magnetic hyperfine interaction parameters (expressed in MHz) were determined for the two nitrogen atoms:A ₁ ⁽¹⁾ =117.95(5),A ₁ ⁽²⁾ =A ₁ ⁽³⁾ =84.48(5),A ₂ ⁽¹⁾ =7.1(1),A ₂ ⁽²⁾ =A ₂ ⁽³⁾ =6.6(1) for M2 andA ₁ ⁽¹⁾ =121.55(5),A ₁ ⁽²⁾ =A ₁ ⁽³⁾ =85.90(5),A ₂ ⁽¹⁾ =6.0(1),A ₂ ⁽²⁾ =5.4(1),A ₂ ⁽³⁾ =5.1(1) for M3. Hyperfine interaction tensors for the nitrogen atom N₁ with a larger interaction have axial symmetry about the <111> direction, but those for the other nitrogen atom, N₂, appear to be small, almost isotropic. Probable models of the M2 and M3 centers are suggested and discussed.     

Ternary copolymers of acrylic acid, <Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide,and butyl acrylate: Synthesis and aggregative behavior in dilute solutions

Narrowly dispersed hydrophilic block and random copolymers of acrylic acid and N-isopropylacrylamide of various compositions and molecular masses are synthesized for the first time by controlled radical polymerization via the reversible addition-fragmentation chain-transfer mechanism. The copolymers are used for the synthesis of ternary copolymers with n-butyl acrylate. As shown by dynamic light scattering, the resulting amphiphilic copolymers can form stable dispersions in diluted aqueous solutions. It is found that the effective hydrodynamic radii of dispersion particles may be controlled via variation both in the primary structure of the ternary copolymer, i.e., the amount and sequence of hydrophilic and hydrophobic units, and in the external stimuli, i.e., the temperature and pH of a solution.     

(3<Emphasis Type="Italic">S</Emphasis>)-4-[(4<Emphasis Type="Italic">R</Emphasis>)-2,2-dimethyl-1,3-dioxolan-4-yl]-3-methylbutan-1-ol—A universal building block for the synthesis of principal fragments of amphidinolides G and H

A new scheme has been proposed for the synthesis of cytotoxic macrocyclic lactones, amphidinolides G and H. Synthetic analogs of the C₇?C₁₄, C₁₅?C₁₉, and C₂₀?C₂₆ fragments of amphidinolides G and H have been prepared from the same starting compound, (3S)-4-[(4R)-2,2-dimethyl-1,3-dioxolan-4-yl]-3-methylbutan-1-ol. The developed procedures and obtained products may be used in the synthesis of related compounds containing similar structural fragments.     

Diastereoselective Allylation of α-Hydroxy Schiff Bases with 2-Substituted Functionalized Allyl Bromides

Russian Journal of Organic Chemistry - The allylation of α-hydroxy Schiff bases with 2-substituted functionalized allyl bromides such as methyl 3-(bromomethyl)but-3-enoate,...     

Computer simulation of the dynamics of crosslinked epoxidized oligobutadienes with different microstructures

The influence of the type of crosslinks and oligomer microstructure on the local mobility of crosslinked epoxidized 1,4-oligobutadienes was studied by molecular dynamics simulation. Distribution histograms and time autocorrelation functions of distances between oxygen and carbon atoms from different chains were examined. The chain microstructure has a substantial effect on all types of molecular motion. After crosslinking via double bonds, crosslinked oligomer molecules with the trans configuration of the double bonds turn out to be more flexible than their cis counterparts.