Synthesis of Novel Exocyclic Allenes with a Norbornene Fragment

Russian Journal of Organic Chemistry - N-Substituted amino acids with a norbornene fragment were synthesized by the direct fusion of amino acids with endic anhydride at 150°C. The synthesized...     

The role of copper(II) ions in the oxidation of 5-hydroxy-6-methyluracil in the ground and electronically excited states with molecular oxygen in aqueous solutions

A spectral fluorescence study of photoinduced reactions in aqueous solutions has been carried out in order to examine the mechanisms of the oxidation of 5-hydroxy-6-methyluracil (I) in the ground and electronically excited states by molecular oxygen in the presence of copper(II) chloride. It has been found that 5,5,6-trihydroxy-6-methylpyrimidine-2,4-dione (II) is formed upon the photolysis of I. The spectral parameters (λ_max) and the quantum yields (φ) of fluorescence (FL) of compounds I (φ = 8 × 10^–4; λ_max = 362 nm) and II (φ = 17 × 10^–4; λ_max = 306, 330 nm) have been determined. A reaction scheme was proposed, according to which the photooxidation of I occurs through the steps of the generation of the radical cation I ^?+ and the superoxide anion О ₂ ^?- with the subsequent formation of 5,5,6-trihydroxy-6-methylpyrimidine-2,4-dione. The catalytic and inhibitory effects of Cu(II) ions on the oxidation of 5-hydroxy-6-methyluracil in the ground and electronically excited states, respectively, by the oxygen radical anion О ₂ ^?- have been revealed.     

Synthesis of an Extractant Based on Neodecanoic Acid for Rare Earth Metal Preconcentration and Separation

Russian Journal of Applied Chemistry - N,N'-(Iminodiethane-2,2'-diyl)di(neodecanamide) was synthesized by thermal condensation of diethylenetriamine with neodecanoic acid. The possibility...     

An NMR Spectral Study of the Structure of 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4-(1H,3H)-dione in DMSO-d6

Journal of Applied Spectroscopy - The structure of 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4(1H,3H)-dione (2) was proven using 13C, 1H, and 15N NMR spectroscopy. A new form (2a) was detected...     

Synthesis of 4-[Alkylsulfanyl(sulfonyl)methyl]isoxazoles and -1<Emphasis Type="Italic">H</Emphasis>-pyrazoles from 3-[(Alkylsulfanyl)methyl]- pentane-2,4-diones

New 4-[(alkylsulfanyl)methyl]- and 4-[(alkanesulfonyl)methyl]isoxazoles and -1H-pyrazoles were synthesized by reactions of 3-[(alkylsulfanyl)methyl]- and 3-[(alkanesulfonyl)methyl]pentane-2,4-diones with hydroxylamine and hydrazine, phenylhydrazine, semicarbazide, or thiosemicarbazide, respectively. The heterocyclization of 3-[(alkylsulfanyl)methyl]pentane-2,4-diones with thiosemicarbazide and semicarbazide hydrochloride was accompanied by elimination of amide or thioamide group. 3-[(Alkanesulfonyl)methyl]pentane- 2,4-diones were found to exist in solution as enol tautomers; they were prepared by oxidation of the corresponding 3-[(alkylsulfanyl)methyl]pentane-2,4-diones with hydrogen peroxide in acetic acid in the presence of a catalytic amount of sulfuric acid.     

Palladium(II) Extraction from Hydrochloric Acid Solutions with 4-[(Hexylsulfanyl)methyl]-3,5-Dimethyl-1H-Pyrazole

Palladium(II) extraction from hydrochloric acid solutions with a novel weakly basic complexing reagent, 4-[(hexylsulfanyl)methyl]-3,5-dimethyl-1H-pyrazole, dissolved in chloroform was studied. Palladium(II) was found to be highly efficiently extracted from 0.1–3 mol/L HCl solutions. A coordination mechanism of palladium(II) extraction with a protonated form of the reagent via fast interphase transfer of ion associates was proposed. The composition of the extracted compound, [PdCl₂μ-L]_n (n > 2), was found, and the way of coordination of the reagent to metal ions through N(2) nitrogen atom and thioether sulfur atom was determined. The reagent can be recommended for concentrating palladium(II) and selectively separating it from platinum(IV), copper(II), nickel(II), and iron(III).     

5-Hydroxy-6-methyluracil as an efficient scavenger of peroxy radicals

The reaction of 5-hydroxy-6-methyluracil with peroxy radicals generated by the thermal decomposition of azodiisobutyronitrile was studied at 75 °C in ethanol, propan-2-ol, and dimethyl sulfoxide. The stoichiometry of the reaction is 1: 1. The reaction product is dihydro-6-hydroxy-6-methylpyrimidine-2,4,5-trione in an anhydrous solvent or dihydro-5,5,6-trihy-droxy-6-methylpyrimidine-2,4-dione in the presence of water. The rate constant for the reaction of 5-hydroxy-6-methyluracil with the peroxy radicals is ∼10⁸ L mol⁻¹ s⁻¹.     

Phase transitions and critical phenomena in multiferroic films with orthorhombic magnetic structure

Phase transitions and critical phenomena in materials with strongly correlated magnetic, ferroelectric, and elastic subsystems are studied. A theoretical study of the influence external fields (dc and ac) have on the dynamics of phase transitions in perovskite-type crystals is performed.     

Synthesis and properties of alkylthiomethylated urea derivatives

Novel N,N′-bis[(alkylsulfanyl)methyl]ureas were prepared by three-component condensation of urea with formaldehyde and thiol in a NaOH solution, and alkylthiomethylated polymethyleneureas were prepared by the condensation of the same reactants in the presence of glacial acetic acid and without it. Polymethyleneureas efficiently sorb silver(I) from nitric acid solutions and palladium(II) from hydrochloric acid solutions. Alcoholsoluble N,N′-bis[(alkylsulfanyl)methyl]ureas inhibit carbon dioxide corrosion of St.3 steel.     

Condensation of Propan-2-one with Formaldehyde and Propane-2-thiol

Three-component condensation of propan-2-one with formaldehyde and propane-2-thiol in the presence of sodium hydroxide afforded 3-{[(propan-2-yl)sulfanyl)]methyl}but-3-en-2-one or 4-[(propan-2-yl)sulfanyl]-3-{[(propan-2-yl)sulfanyl]methyl}butan-2-one, depending on the amount of the base. The formation of 4-[(propan-2-yl)sulfanyl]-3-{[(propan-2-yl)sulfanyl]methyl}butan-2-one from 4-[(propan-2-yl)sulfanyl]butan-2-one involved aldol condensation of the latter with formaldehyde and subsequent nucleophilic addition of propane-2-thiol to the C=C double bond of intermediate 3-{[(propan-2-yl)sulfanyl]methyl}but-3-en-2-one in the presence of sodium hydroxide.