Nonglycoside analogs of nucleotides

Conclusions We synthesized nine analogs of dinucleoside monophosphates that contain 9-(2-hydroxyethyl)adenine, 9-(3-hydroxypropyl)adenine, and 9-(4-hydroxybutyl)adenine as the 3 residue, and the natural nucleosides: uridine, cytidine, adenosine, guanosine, and inosine as the 5 residue.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 915–916, April, 1975.     

Chemical biology of protein lipidation: semi-synthesis and structure elucidation of prenylated RabGTPases

Rab/Ypt guanosine triphosphatases (GTPases) represent a family of key membrane traffic regulators in eukaryotic cells. For their function Rab/Ypt proteins require double modification with two covalently bound geranylgeranyl lipid moieties at the C-terminus. Generally, prenylated proteins are very difficult to obtain by recombinant or enzymatic methods. We generated prenylated RabGTPases using a combination of chemical synthesis and protein engineering. This semi-synthesis depends largely on the availability of functionalized prenylated peptides corresponding to the proteins' native structure or modifications. We developed solution phase and solid phase strategies for the generation of peptides corresponding to the prenylated C-terminus of Rab7 GTPase in preparative amounts enabling us to crystallize the mono-prenylated Ypt1:RabGDI complex. The structure of the complex provides a structural basis for the ability of RabGDI to inhibit the release of nucleotide by Rab proteins and a molecular basis for understanding a RabGDI mutant that causes mental retardation in humans.     

Reaction of aromatic amines with vinyl alkyl ethers

Summary Aromatic amines such as aniline, p-anisidine, and p-bromoaniline in the presence of BF₃ etherate react with vinyl alkyl ethers to form 1-alkoxy-tetrahydroquinaldine derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12 p. 2221–2222, December, 1964     

Fluctuations and dynamics of chemical reactions near neutral steady-state

The effect of fluctuations on the behavior of a simple kinetic model of catalytic reactions allowing a neutral steady-state, is analyzed.

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Conformational analysis of 3-borabicyclo[3.3.1]nonane derivatives

Conformations of 3-borabicyclo[3.3.1]nonane derivatives have been studied by means of ¹H and ¹³C NMR spectroscopy. With the aid of the coupling constants ³J(HH) and ¹³C chemical shifts it has been shown that all the derivatives of 3-borabicyclo[3.3.1]nonane with the trigonal boron atom studied are in a flattened double-chair conformation. In 3-borabicyclo[3.3.1]nonane derivatives with the tetra-coordinated boron atom and substituents at the 7α-position, the chair-boat conformation predominates, the boat conformation being characteristic of the cyclohexane ring; exceptions are the compounds with the internal donor—acceptor bond between the boron atom an 7α-substituent.     

Impurity and “surface” states in linear molecular systems

Within the approximation of strongly bound electrons the Green's functions in a lattice point representation are found for various linear chains and for a simple cubic lattice. These functions are subsequently used to calculate the impurity and surface states in semi-infinite and finite chains. The spectrum of the simplest model of a monodispersed polymer is calculated.     

Effect of epitaxial growth on the formation of the cobalt catalysts of the Fischer-Tropsch synthesis

Mixed oxides Co_xAl_yO₄ with different Al/Co ratios applied as supports for the catalysts of the Fischer-Tropsch synthesis were prepared using the solid-state chemical reaction. The Co_xAl_yO₄ supports were prepared by modifying gibbsite with various cobalt salts (acetate, nitrate, and basic carbonate). The use of basic cobalt carbonate gives the Co(20%)/Co_xAl_yO₄ catalyst, which provides an increased yield of hydrocarbons C₅₊ and a decreased methane content compared to the impregnation catalyst Co(30%)/Al₂O₃. The introduction of small amounts of rhenium additives makes it possible to enhance the yield of hydrocarbons C₅₊ (179 g m⁻³) and also to increase the selectivity with respect to the C₅–C₁₈ fraction. The introduction of basic cobalt carbonate into the support, most likely, creates favorable conditions for the epitaxial growth of the precursor of the active phase. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1856–1860, September, 2007.     

Convenient synthesis of 5′-methyl-2′-desoxyuridines

A convenient method has been developed for the synthesis of 5-methyl-2-desoxyuridines. Chlorination of 5-O-benzoyl-5-methyluridines with a mixture of Ph₃P and CCl₄ in DMF affords the 2-desoxy-2-chloro-derivatives, which are then reduced with tributyltin hydride. The crystalline 5-O-benzoyl-5-methyl-2-desoxyuridines were obtained in overall yields of 40–60%. In a similar way, 5-O-benzoyluridine has given 5-O-benzoyl-2-desoxyuridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 246–248, February, 1989.     

Two mechanisms of the interaction between atoms and solids

The chemical action of atoms on solids can be due to both direct reactions with the structural units of solids and heterogeneous recombination energy transfer to the crystal lattice.

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The Crystal Structures of Rubidium and 4-Amino-1,2,4-Triazolium Tetrafluoroantimonates(III)

The crystal structures of complex antimony(III) fluorides RbSbF₄ (I) and (C₂N₄H₅)SbF₄ (II) were determined. The crystals of I and II are monoclinic; for I: a = 4.628(1) Å, b = 6.167(1) Å, c = 7.922(1) Å, = 100.582(3)°, V = 222.24(7) ų, Z = 2, (calcd.) = 4.23 g/cm³, (exp.) = 4.25 g/cm³, F(000) = 248, space group P2₁/m, R = 0.0395; for II: a = 4.678(1) Å, b = 7.339(4) Å, c = 10.185(1) Å, = 90.88(2)°, V = 349.6(2) ų, Z = 2, (calcd.) = 2.69 g/cm³, (exp.) = 2.70 g/cm³, F(000) = 264, space group P2₁. The structure of I is formed by Rb⁺ cations and [SbF₄] ^n– _n anionic chains composed of SbF₅E octahedra with two bridging fluorine atoms. The structure of IIis formed by (C₂N₄H₅)⁺ cations and isolated [SbF₄]^– anions in which the antimony polyhedra are SbF₄E trigonal bipyramids. The relationship between the crystal structures and electrophysical and biological properties of single-charged cation tetrafluoroantimonates(III) was studied.