Electrochemical polymerization of <Emphasis Type=Italic>N</Emphasis>,<Emphasis Type=Italic>N</Emphasis>′-bis(3-methoxysalicylidene)-1,3-propylenediamine

The electrochemical oxidation of N,N′-bis(3-methoxysalicylidene)-1,3-propylenediamine leads to the formation of conducting polymer on the electrode surface. The decisive role of phenol oxygen in the formation of the polymeric forms of azomethine bases was elucidated. Optimal conditions for the synthesis of the polymer in the potentiostatic conditions were revealed. The coefficient of the charge diffusion and the activation barrier for the charge transfer in the polymer bulk in the electrolyte medium were determined.     

Facile synthesis and biological evaluation of novel fluorine-containing <Emphasis Type=Italic>N</Emphasis>-nitro-<Emphasis Type=Italic>N</Emphasis>′-substituted phenylurea

Twenty-two novel N-nitro-N′-substituted phenyl-N-(2,6-dibromo-4-fluorophenyl)urea derivatives were designed and synthesized via a simple and convenient BTC ‘one-pot’ procedure using DMAP as the catalyst. The structures of all newly synthesized compounds were confirmed by IR, ¹H NMR, and elemental analysis, and a part has been identified by ¹³C NMR. The preliminary bioassay indicates that the target compounds possesses moderate herbicidal activity against Sorghum sudanense. However, some of the title compounds presented high plant growth regulating activity against rape.     

Activation energy (Δ<Emphasis Type=Italic>G</Emphasis>*), enthalpy (Δ<Emphasis Type=Italic>H</Emphasis>*), and entropy (Δ<Emphasis Type=Italic>S</Emphasis>*) of some indoles and certain of their binary mixtures

Thermodynamic parameters, like, change of activation energy for dipole orientation (ΔG*), enthalpy (ΔH*), and entropy (ΔS*) of activation in the case of binary-, ternary-, etc. mixtures of polar molecules in pure liquid phase or in dilute solution phase in a non polar solvent helps in drawing certain quantitative conclusions regarding their relaxation behavior as to whether a single component is responsible for observed microwave absorption or a cooperative phenomenon (average) by all the dipoles of the mixture contribute to it. Dielectric relaxation behavior of polar molecules in a non-polar solvent, or mixtures of these substances at different microwave frequencies and over a range of temperatures and concentrations give a method of determining these quantities. Such an experimental investigation on verity of systems is necessary to draw quantitative conclusions regarding the system of the molecules which are not studied so as to examine if the results obtained are in favor or against the general conclusions already arrived at, in other systems. With this in view, systematic dielectric measurements in a range of temperatures are carried out at a single microwave frequency on a single weight fraction in benzene of the four substituted indoles, namely, 5-Bromoindole, 5-Fluoroindole, 2,3-Dimethylindole, 2,5-Dimethylindole and on binary (1:1) mixtures of 2,5-Dimethylindole + 5-Bromoindole and 2,3-Dimethylindole + 5-Fluoroindole in benzene as solvent at different temperatures. The results are presented and discussed.     

First example of the synthesis of <Emphasis Type="Italic">S</Emphasis>,<Emphasis Type="Italic">O</Emphasis>-macroheterocycle based on 2(5<Emphasis Type="Italic">H</Emphasis>)-furanone and 2,2´-oxydiethanethiol

A base-catalyzed reaction of 3,4-dichloro-5-methoxy- and 3,4-dichloro-5-ethoxy-2(5H)-furanones with 2,2´-oxydiethanethiol gave thiols and bis-thioethers of 2(5H)-furanone series. A new S,O-macroheterocyclic compound containing a 18-membered oxathiamacrocycle and two 2(5H)-furanone fragments was synthesized based on the thiols in an aqueous solution of potassium hydroxide, which was characterized by X-ray diffraction.     

Synthesis of a chiral block for С<Superscript><Emphasis Type=Italic>1</Emphasis></Superscript>–С<Superscript><Emphasis Type=Italic>5</Emphasis></Superscript> fragment of epothilones

Synthesis was developed of a new chiral block for epothilone analogs from R-(?)-pantolactone.     

A Lemieux–Johnson oxidation of shikimic acid derivatives: facile entry to small library of protected (2<Emphasis Type="Italic">S</Emphasis>,3<Emphasis Type="Italic">S</Emphasis>,4<Emphasis Type="Italic">R</Emphasis>)-2,3,4,7-tetrahydroxy-6-oxoheptanals

The Lemieux–Johnson oxidation was employed for the cleavage of the carbon–carbon double bond of shikimic acid derivatives. Through this procedure, a series of the sixteen novel (2S,3S,4R)-2,3,4,7-tetrahydroxy-6-oxoheptanals bearing three contiguous stereocentres have been synthesized in excellent yields.     

Unusual transformation of (1<Emphasis Type="Italic">R</Emphasis>,1′<Emphasis Type="Italic">S</Emphasis>,2<Emphasis Type="Italic">S</Emphasis>)-1-(3-diisopropylamino-3-oxopropyl)-2-(1-hydroxyethyl)cyclopropane in the course of the cyclopropylcarbinyl rearrangement

The cyclopropylcarbinyl rearrangement of (1R,1′ S,2S)-1-(3-diisopropylamino-3-oxo-propyl)-2-(1-hydroxyethyl)cyclopropane and the participation of the amide moiety in the intramolecular process smoothly affords the (2′ E,5S)- N,N-diisopropyl-N-[5-(but-2′-enyl)tetra-hydrofuran-2-yridene ] ammonium salt.     

Crystal and Molecular Structure of (4′<Emphasis Type="Italic">R</Emphasis>,5′<Emphasis Type="Italic">R</Emphasis>,22<Emphasis Type="Italic">R</Emphasis>)-22-Hydroxy-22-(3′,4′-dimethylisoxazolin-5′-yl)-6β-methoxy-3α,5-cyclo-23,24-dinorcholane

The crystal and molecular structure of (4′R,5′R,22R)-22-hydroxy-22-(3′, 4′-dimethylisoxazolin-5′-yl)-6β-methoxy-3α,5-cyclo-23,24-dinorcholane was studied by single crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group C2; a 19.649(7), b 7.680(2), c 17.254(6) Å; β 101.05(3)°. The only diastereomer formed by the 1,3-dipolar cycloaddition of acetonitriole oxide has the 4′R,5′R stereochemistry of the arising chiral centers. The conformation of the side chain of the molecule is additionally stabilized by an intramolecular hydrogen bond.