Two Isomers of C6H6F9O9Tb

Two isomers with empirical formula C₆H₆F₉O₉Tb are synthesized and their structures are studied. Isomerism was found to arise due to different positions of a proton. Crystals of two isomers are isostructural and form continuous series of solid solutions with C₆H₆F₉O₉Eu.     

Synthesis and properties of enamine derivatives of 1-methyl-2-phenyl-5-pyrrolone and 5-thiopyrrolone

The corresponding dimethylaminomethylene derivative, from which a number of similar compounds were synthesized by reaction with amines, was obtained by the reaction of 1-methyl-2-phenyl-2-hydroxy-5-oxotetrahydropyrrole with dimethylformamide in the presence of phosphorous oxychloride. The formyl derivatives of 1-methyl-2-phenyl-5-pyrrolone and 5-thiopyrrolone were obtained, and the UV and IR spectra of the enamines of these compounds were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 791–793, June, 1972.     

Kinetic regularities of erythrocyte hemolysis and hemoglobin oxidation under the action of sulfur-nitrosyl iron complexes as nitric oxide donors

The kinetics of erythrocyte hemolysis and intra-erythrocyte hemoglobin oxidation under the action of synthetic sulfur-nitrosyl iron complexes was studied. The complexes capable of releasing nitric oxide due to spontaneous hydrolytic decomposition was studied. The addition of these complexes to a 0.2% suspension of mouse erythrocytes results in hemolysis. The kinetic curves of hemolysis exhibit an induction period, whose duration is different for each complex. The hemolysis is preceded by hemoglobin oxidation with nitric oxide penetrating into the cell. The oxidation of hemoglobin follows the first-order rate equation. The apparent first-order rate constants characterizing the NO-donating ability of each complex were determined. The hemolytic effect of the studied complexes is suggested to be related to the formation of peroxynitrite inside erythrocytes. Peroxynitrite is the cytotoxic product of interaction of nitric oxide and the superoxide radical anion.     

The Efficiency of the Formation of Singlet Oxygen by a Sensitizer Based on Zinc Phthalocyanine

Using zinc octa(diethoxyphosphenylmethyl)phthalocyanine as an example, we determined experimentally the quantum yield of generation of singlet oxygen () which makes it possible to evaluate quantitatively the efficiency of photogeneration of ¹O₂ and the influence of biomolecules on this parameter. It is shown that the efficiency of generation of singlet oxygen by the sensitizers used in photodynamic therapy depends on their state in a solution and increases with disaggregation of the dye and its interaction with biomolecules. It is established that phthalocyanine in an aqueous buffer solution sensitizes the formation of ¹O₂ with the quantum yield = 0.16 ± 0.02. On introduction of the detergent Triton X100 into the buffer solution of phthalocyanine, increases up to 0.48 ± 0.07. In a microheterogeneous medium (buffer + albumin) = 0.42.     

Salt effects and the mechanism of electrophilic mercuration of unsaturated compounds

The reaction of Hg(OAc)₂ with bornylene in THF-H₂O and CH₃CN-H₂O mixed solvents (75 25, v/v) was studied. The effects of the addition of NaOAc on the reaction rate and the composition of products were investigated. In the CH₃CN-H₂O mixture, the addition of NaOAc decreases the amount of the rearranged product, fundamentally changes the ratio between the regioisomeric solvoadducts, and promotes the formation of products of Hg(OAc)₂ addition. The reaction proceedsvia an ion pair and free mercurinium ion; the cation of the ion pair and the free mercurinium ion have dissimilar structures.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 544–548, March, 1995.     

Photolysis of Phenol and para-Chlorophenol by UV Laser Excitation

The photolysis of phenol and para-chlorophenol by irradiation with the fourth harmonic of a neodymium laser was examined using electronic absorption spectroscopy, fluorescence, and quantum-chemical techniques. It was found that the introduction of a chlorine atom into the phenol molecule increases the efficiency of photolysis of para-chlorophenol by excitation in the long-wavelength absorption band. The O–H and C–Cl bonds in the test compounds are ruptured via a predissociation mechanism in triplet states localized at the breaking bonds.     

Fucoidans from Brown Seaweeds <Emphasis Type="Italic">Sargassum hornery</Emphasis>, <Emphasis Type="Italic">Eclonia cava</Emphasis>, <Emphasis Type="Italic">Costaria costata</Emphasis>: Structural Characteristics and Anticancer Activity

Fucoidans were isolated by water extraction and ion-exchange chromatography from brown algae Eclonia cava, Sargassum hornery, and Costaria costata collected near of Korean coasts. The structures of fucoidans were investigated. Fucoidan from E. cava was mixture of sulfated rhamnogalactofucan and galactofucan. Fucoidan from C. costata was a sulfated galactofucan. Fucoidan isolated from S. hornery was separated into three fractions: a homofucan sulfate, a homofucan but without sulfate groups, and a sulfated rhamnofucan. The results clearly showed that fucoidans play an inhibitory role in colony formation in human melanoma and colon cancer cells and may be effective antitumor agents.