Preparation and Ion-Exchange Properties of Mixed Zirconium(IV) Phosphate-Phosphonate Sorbents

Composite sorbents based on Zr(IV) phosphate-hydroxyethylidenediphosphonate with different phosphate-phosphonate ratio were prepared. These sorbents were characterized by elemental analysis, X-ray diffraction, and IR spectroscopy, and their ion-exchange sorption capacity for several transition metals and strontium was studied. The sorption capacity of these sorbents increases with increasing pH.     

Voltammetry of Formaldehyde at Mechanically Renewable Solid Electrodes

The electrochemical behavior of formaldehyde (CH₂O) at solid electrodes made of platinum, gold, silver, cobalt, nickel, copper, and graphite was studied. The working surface of the electrodes was renewed by cutting a thin layer (0.5 m) immediately in the test solution. It was found that, in alkaline solutions, CH₂O was oxidized at all electrodes other than cobalt and graphite ones while scanning the potential to the anode and cathode regions. The peaks of CH₂O oxidation at platinum and gold electrodes using potential scanning in the anode and cathode directions, as well as at nickel, copper, and silver electrodes using potential scanning in the anodic direction, are suitable for analytical purposes.     

Research in the imidazole series. 96. Reaction of 1-methyl-4-nitro-5-chlorimidazole with phenols, naphthols, and 8-hydroxyquinoline

By reactions of 1-methyl-4-nitro-5-chlorimidazole with 4-nitrophenol, - and -naphthols, and 8-hydroxyquinoline, a number of 1-methyl-4-nitro-5-aryl(heteryl)oxyimidazoles have been obtained. With aminophenols, under analogous conditions, 1-methyl-4-nitro-5-hydroxyphenylaminoimidazoles have been obtained.For Communication 95, see [1].Novokuznetsk Scientific-Research Chemical-Pharmaceutical Institute, Novokuznetsk 654034, Russia. Center for Medicinal Chemistry, All-Russian Scientific-Research Chemical-Pharmaceutical Institute, Moscow 119815. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 327–329, March, 1998.     

Thermal decomposition of transition metal carboxylates

Thermal solid-phase decomposition of anhydrous copper(ii) formate has been studied at 120–180 ° The rate of gas evolution during the decomposition depends on the depth of conversion and can be presented as the sum of first-order reaction rates and the rate of the autocatalytic process (a second-order reaction). The evolution of the solid phase during thermolysis has been observed by optical microscopy. The decomposition of copper formate is a complex topochemical process, a combination of homogeneous and heterogeneous transformations and dispersion of large crystals.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. l, pp. 72–76, January, 1996.     

Nucleophilic substitution in the furazan series. Reactions of nitrofurazans with ammonia

The reactions of 3-nitro-4-R-furazans with ammonia were studied. The effect of the substituent R on the specific features of the nucleophilic substitution reaction observed was considered. The nitro group attached to the furazan ring can act as both the leaving group and the activating group facilitating the displacement of the second substituent (for example, OR" or N(NO₂)R").     

X-ray Study of Iron-containing Derivatives of Arabinogalactan

Iron-containing derivatives of arabinogalactan (ferroarabinogalactans) were subjected to X-ray diffraction analysis to determine the form and structure of bound iron. Crystal lattice parameters a of the iron-containing phase were measured and the average crystallite size was determined.     

Preparation and reactivity of metal-containing monomers

The thermal decomposition of iron (III) acrylate, [Fe₃O(CH₂=CHCOO)₆ · 3H₂O]OH (FeAcr), a monomer with a complex cluster cation, has been studied at 200–370 °C. Thermal transformations of FeAcr occur in two temperature regions. The rates of gas evolution in the low temperature region (200–300 °C) and the high temperature region (300–370 °C) are described by first-order equations withk=4.2 · 10²¹exp[−59000/(RT)] s⁻¹ andk=1.3 · 10⁶exp[−30500/(RT)] s⁻¹, respectively. A study of the qualitative and quantitative composition of the products of FeAcr thermolysis was carried out. The thermal transformation of FeAcr is a complex process of dehydration, degradation, and polymerization in the solid phase followed by decarboxylation of the metal-carboxyl groups of the polymer. for part 33 see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1743–1750, October, 1993.     

Redox reactions of arabinogalactan with silver ions and formation of nanocomposites

Formation of silver nanoparticles in the course of chemical reduction of AgNO₃ with arabinogalactan in aqueous alkaline solution was studied by electronic absorption spectroscopy and X-ray diffraction analysis. The pH of the solution was found to be the major factor affecting the degree of reduction of Ag⁺ ions. The probable reaction mechanism was discussed. Composites containing up to 58% Ag, with the metal particle size of 7–16 nm, were prepared. The nanoparticle size can be controlled by varying the reactant ratio AgNO₃: arabinogalactan. Chemical modification of arabinogalactan was confirmed by IR and ¹³C NMR spectroscopy and by TLC.     

Synthesis and some properties of 6-β-oxoalkyl(aralkyl,hetaralkyl, cycloalkyl)thiopurines

The reaction of 6-purinethione with -haloketones has given a series of new 6--oxoalkyl(aralkyl, hetaralkyl, cycloalkyl)thiopurines. Their alkylation in position 9 and acid hydrolysis to hypoxanthine and its 9-alkyl derivatives has been studied. The hydrolysis of the acetals of 6-formylmethylthiopurine and the oxidation of 6-(2,3-dihydroxypropyl)thiopurine leads to 6-formylmethylthiopurine, which shows a ring-chain tautomerism and exists in the form of 7-hydroxy-7,8-dihydrothiazolo[2,3-i]purine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1548–1553, November, 1993.     

Novel functional activities of anti-dna autoantibodies from sera of patients with lymphoproliferative and autoimmune diseases

DNA-hydrolyzing activity of IgG autoantibodies from sera of patients with various types of lymphoproliferative diseases was investigated. The association of DNA-hydrolyzing activity with the antibody (Ab) fraction has been proved by newly developed affinity-capture assay. Study of abzyme incidence in blood tumors and systemic lupus erythematosis (SLE) revealed linkage of anti-DNA Ab catalysts to mature B-cell tumors, and increased probability of DNA-abzymes formation on the background of autoimmune manifestations. These data suggest possible similarity between mechanisms of abzyme formation in SLE and B-cell lymphomas. A new mechanism of formation of DNA-specific catalytic Abs has been proposed based on the increased crossreactivity of polyclonal DNA-abzymes to DNA-depleted nuclear matrix proteins. The possibility of the abzyme production as Ab to the energetically destabilized ground state of the antigen has been discussed. Preliminary results were obtained that indicate the complement-independent cytotoxicity of anti-DNA autoantibodies isolated from blood of patients with SLE and chronic lymphocytic leukemia.