Analogs of carbohydrate-metabolism coenzymes

Conclusions We synthesized two analogs of the natural coenzyme adenosine diphosphate glucose: N₆-methyl-ADPG and N₆, N₆-dimethyl-ADPG.For communication 11, see [1].The following abbreviations are used in this article: ADPG) adenosine-5'-diphosphate-a-D-glucopyranose; N₆-methyl-ADPG) N₆-methylamino-9--D-ribofuranosylpurine-5-diphosphate--D-glucopyranose; N₆, N₆-dimethyl-ADPG) N₆, Ng-dimethylamino-9--D-ribofuranosylpurine-5-diphosphate--D-glucopyranose.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2514–2521, November, 1969.     

Chemiluminescence and auto-oscillations in the (S?Cr2O72+?UO22+) system

Quasi-harmonic oscillations of chemiluminescence intensity at certain concentrations of the components for the (S–Cr₂O ₇ ^2– –UO ₂ ²⁺ ) system in concentrated sulfuric acid and chemiluminescence and dark stages with the participation of intermediates Cr(V), U(IV) and sulfur peroxide radicals (HS₂O₆ ^.) have been discovered. Chemiluminescence is attributed to the interaction of HS₂O₆ ^. compounds. The processes of deactivation of the excited states of uranyl involve the participation of Cr(V). A scheme for the oscillation chemiluminescence reactions is suggested.

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(S–Cr₂O ₇ ^2– –UO ₂ ²⁺ ) H₂SO₄ , . Cr(V), U(IV) (HS₂O₆ ^.) HS₂O₆ ^. Cr(V) . .

     

The four main types of some precipitation diagrams determined by tyndallometric technique

Summary By experimental investigation of precipitation systems were found the four different types of precipitation diagrams: A ionic solubility, B formation of ionic pairs and of associates, C neutralization and D unsymmetrical ionic reactivity. It appears to, be very important to distinguish the nature of precipitation systems, because of general view of precipitation diagrams, and because of conclusion about the behaviour of ions in the solutions.

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Zusammenfassung Durch tyndallometrische Messungen wurde die Fällung vonSalien untersucht. Bei der Darstellung des Ergebnisses in Precipitation diagrams PD (lg C_Kation gym lg C_Anion) wurden 4 Haupttypen (A, B, C, D) gefunden. Beispiele sind Hg₂SO₄ (A), Cu(OH)₂ (B), Bi(OH)₃ (C) und AgSCN (D).

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With 4 figures     

Revealing the importance of linkers in K-series oxime reactivators for tabun-inhibited AChE using quantum chemical,docking and SMD studies

Inhibition of acetylcholinesterase (AChE) with organophosphorus compounds has a detrimental effect on human life. Oxime K203 seems to be one of the promising reactivators for tabun-inhibited AChE than (K027, K127, and K628). These reactivators differ only in the linker units between the two pyridinium rings. The conformational analyses performed with quantum chemical RHF/6-31G* level for K027, K127, K203 and K628 showed that the minimum energy conformers have different orientations of the active and peripheral pyridinium rings for these reactivator molecules. K203 with (–CH₂–CH=CH–CH₂–) linker unit possesses more open conformation compared to the other reactivators. Such orientation of K203 experiences favorable interaction with the surrounding residues of catalytic anionic site (CAS) and peripheral anionic site (PAS) of tabun-inhibited AChE. From the steered molecular dynamics simulations, it has been observed that the oxygen atom of the oxime group of K203 reactivator approaches nearest to the P-atom of the SUN203 (3.75 Å) at lower time scales (less than ~1000 ps) as compared to the other reactivators. K203 experiences less number of hydrophobic interaction with the PAS residues which is suggested to be an important factor for the efficient reactivation process. In addition, K203 crates large number of H-bonding with CAS residues SUN203, Phe295, Tyr337, Phe338 and His447. K203 barely changes its conformation during the SMD simulation process and hence the energy penalty to adopt any other conformation is minimal in this case as compared to the other reactivators. The molecular mechanics and Poisson–Boltzmann surface area binding energies obtained for the interaction of K203 inside the gorge of tabun inhibited AChE is substantially higher (?290.2 kcal/mol) than the corresponding K628 reactivator (?260.4 kcal/mol), which also possess unsaturated aromatic linker unit.     

Formation of the fullerene radical anion in the reaction of C60 with phosphorous triamides

Fullerene C₆₀ reacts with phosphorous acid triamides to give the radical anion. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 201–203, January, 2008.     

Mercury methylation in a tropical macrophyte: influence of abiotic parameters

Sediment has been considered to be one of the most important mercury methylation sites, but recent studies have demonstrated a new site that is relevant, i.e. the roots of floating aquatic macrophytes, where high methylation is observed. The effects of temperature, pH and electric conductivity on net mercury methylation were studied in the roots of the water‐hyacinth Eichhornia crassipes of a freshwater coastal lagoon (Lagoinha, RJ, Brazil). Root samples were incubated, over three days, with ²⁰³HgCl₂ addition, at different temperatures (10–90 °C), pH values (3–8) and different electrolytic solutions (KClO₄, KCl and CaCl₂, at 1, 5, 10, 25 and 50 mM , ranging between 18 and 760 µS cm⁻¹). ²⁰³Hg‐labeled methylmercury (Me²⁰³Hg) was extracted in toluene, after acid leaching, and measured by β‐counting. Up to 35% of mercury added was converted to MeHg Methylation increased from 10 to 35 °C, and decreased thereafter. The process was completely inhibited at 90 °C. At pH values of 6 and 7 methylation was stimulated and a significant decrease was verified at pH 8. Increasing KClO₄ concentrations led to a significant decrease in the methylation rates, while for KCl and CaCl₂ solutions only a slight decrease was observed. Copyright © 1999 John Wiley & Sons, Ltd.     

An Amidinate‐Stabilized Germatrisilacyclobutadiene Ylide

The synthesis and characterization of new amidinate‐stabilized germatrisilacyclobutadiene ylides [L₃Si₃GeL′] (L=PhC(NtBu)₂; L′=ËL; Ë=Ge ( 3 ), Si ( 7 )) are described. Compound 3 was prepared by the reaction of [LSi? SiL] ( 1 ) with one equivalent of [LGe? GeL] ( 2 ) in THF. Compound 7 was synthesized by the reaction of 2 with excess 1 in THF. The bisamidinate germylene [L₂Ge:] ( 4 ) is a by‐product in both reactions. Moreover, compound 7 was prepared by the reaction of 3 with one equivalent of 1 in THF. Compounds 3 and 7 have been characterized by NMR spectroscopy, X‐ray crystallography, and theoretical studies. The results show that compounds 3 and 7 are not antiaromatic. The puckered Si₃Ge four‐membered rings in 3 and 7 have a ylide structure, which is stabilized by amidinate ligands and the electron delocalization within the Si₃Ge four‐membered ring.     

Separation and detection of traces of copper,iron and manganese in cotton materials by TLC

Summary A TLC method for the fast detection of copper, iron and managanese ions in cotton materials is described. The optimal solvent system is 812 (v/v), acetone: HCl:H₂O and the locating reagent is rubeanic acid followed by exposure to ammonia vapour. It was found that in cotton materials, metal ions can be detected at a lower limit of 20 g per gram of material.     

Chemical recovery of thallium-203 following production and separation of lead-201

Because of the cost and limited availability of isotopically enriched thallium (>92%²⁰³Tl), its use in the²⁰³Tl(p, 3n)²⁰¹Pb nuclear reaction necessitates chemical recovery. An adaptive method has been developed and evaluated. After the separation of²⁰¹Pb, the²⁰³Tl(I) is oxidized to²⁰³Tl(III) by Cl₂, Br₂ or [Fe(CN)₆]⁻², precipitated as Tl(OH)₃ with NaOH and subsequently converted to Tl₂O₃ by heating. Due to potential loss during recovery, the solubilities of Tl(OH)₃ and Tl₂O₃ in aqueous solution as a function of pH have been studied using the internal tracer²⁰²Tl (T=12.2d), produced during cyclotron irradiation. Effective solubility product constants have been determined to be 5.4·10⁻⁴⁸ and 2.5·10⁻⁴⁷ for Tl(OH)₃ and Tl₂O₃, respectively.     

Synthesis of the metabolites of 4-(2-methyl-1H-imidazol-1-yl)-2,2-diphenylbutanamide (KRP-197/ONO-8025)

We synthesized the six presumed metabolites (2--7) of 4-(2-methyl-1H-imidazol-1-yl)-2,2-diphenylbutanamide [KRP-197/ONO-8025, 1], a urinary incontinence therapeutic agent, in order to confirm the structures of the metabolites. Metabolite (2) was synthesized via glucuronidaion of compound (1) and methyl 2,3,4-tri-O-benzoyl-1-methanesulfonyl-alpha-D-glucopyranuronate. Metabolite (3) was synthesized via 3-(tert-butoxycarbonyl)-2-methyl-1,3-imidazolidine-4,5-dione. Metabolites (4--7) were synthesized via 4-amino-2-diphenylbutanamide, respectively. The structures of the metabolites (2--7) in humans were identified by means of synthesis of the authentic compounds.     

Differential determination of203Hg and14C or35S in double labelled biological samples

The differential determination of²⁰³Hg and¹⁴C or³⁵S in double labelled biological samples is presented. The biological samples were mineralized with 70% HClO₄ and 30% H₂O₂ in minivals MILLI-6. The γ-activity of²⁰³Hg was measured on a well scintillation counter. The total activity, due to²⁰³Hg and¹⁴C or³⁵S, was measured by the liquid scintillation technique after addition of Aquasol into the same vials. The method of external standard channel ratio was used for standardization. Very good recoveries were obtained: 100±0.7% for²⁰³Hg and 94.6–101.0% for¹⁴C and³⁵S. This method could be used for other β, γ and β-active nuclides with similar β-spectra.     

The structure of a new germacranolide — Shonachalin C — FromArtemisia fragrans

The structure of the new germacranolide shoanchalin C (C₁₅H₂₂O₄, mp 203–205°C) isolated fromArtemisia fragans has been established on the basis of spectroscopic (IR,¹H and¹³C NMR) results.     

Exchange of mercury between mercuric ions and methylmercuric nitrate

The rate constant for the exchange between Hg²⁺ and CH₃Hg⁺ ions in a Cl-free 1NH₂SO₄ solution at 25°C was measured with²⁰³Hg as a radiotracer and separation of the two compounds by liquid extraction of the organic species into benzene from a NaCl- or NaI-solution.     

Synthesis of novel [1-aziridinyl-(hydroxyimino)methyl]arenes and their cytotoxic activity

The synthesis has been developed for novel potential anticancer agents whose structures contain an aziridine amidoxime group. The cytotoxic activity of all of the target compounds on different cell lines are given together with the in vitro IC₅₀ and LD₅₀ values found. The most promising anticancer agents were found to be the methyl 4-[1-aziridinyl(hydroxyimino)methyl]benzoate, 1-aziridinyl(2-naphthyl)-methanone oxime, and 1-aziridinyl(2-quinolyl)methanone oxime. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 203–213, February, 2009.     

Die Phase La2U2N5

In the system U–La–N a new phase of composition La₂U₂N₅ was observed. The differaction pattern of this phase can be indexed with a tetragonal unit cell:a=8.43 Å,c=8.50 Å andc/a=1.008. The pseudocubic sub-cell withaca/2 is closely related to the CsCl-type.

Auszug aus der von der Technisch-Naturwissenschaftlichen Fakuktät der TU Wien approbierten Diplomarbait des Herrn Dipl.-Ing.J. Waldhart.     

Fast and high-yield synthesis of radioactive CH3203Hg(II)

A simple and fast synthesis of radioactive methylmercury is presented. It is based on the methylation of inorganic ²⁰³Hg(II) by methylcobalamin and isolation of resulting CH₃²⁰³Hg(II) in a single extraction step. Time required is less than 4 hours and the final yield is ⩾90%. © 1997 John Wiley & Sons, Ltd.     

Authors index to volume 87

Nuclear relaxation times T₁ and T_1p and T₂ of two Tl isotopes, ²⁰³Tl and ²⁰⁵Tl, in solid TINO₂ were measured betwe en 120 and 430 K. The shorter component of the highly non-exponential T₁ decay shows two minima above and below room temperature, which were assigned to Tl⁺ ionic diffusion to NO^-₂ reorientation.     

Motions of Trimethylphosphine Oxide in Carbon Nanotubes as Revealed by Solid‐state NMR

Trimethylphosphine (TMP) has been adsorbed in carbon nanotubes and oxidized to trimethylphosphine oxide (TMPO). ³¹P spin–lattice relaxation T ₁ measurements at temperatures from 203 to 333 K have been employed to investigate the motions of TMPO. The ³¹P T ₁ is found to be monoexponential and isotropic. The activation energy is measured as 4.4 ± 0.3 kcal•mol⁻¹, which is comparable to that of TMP adsorbed on Lewis acid sites in zeolites.     

Thermodynamic,kinetic, and conductivity studies of an order-disorder transition in Li4Zn(PO4)2

Calorimetric measurements by differential scanning calorimetry gave a value of 2.6 kJ/mole for the enthalpy of the order-disorder transition observed in Li₄Zn(PO₄)₂ at 445°C. Conductivity measurements gave activation energies of 109 and 203 kJ/mole, above and below the transition temperature, respectively. The difference, 94 kJ/mole, is attributed to the activation enthalpy for the disordering transition. Li₄Zn(PO₄)₂ has a low Li⁺ ion conductivity, 10⁻⁵ ohm⁻¹ cm⁻¹ at 400°C.     

Vernetzte Gleichgewichte: Verhalten von lod gegenüber Petrolether,Wasser und Kaliumiodid

Because of the formation of KI₃, potassium iodide increases the extraction rate of iodine from petroleum ether into water. Nernst's constant of the distribution of iodine in the system water/petroleum ether (KN = 34.1 ± 4.6) and the equilibrium constant of the formation of KI₃ from iodine and potasium (K_K = 820 ± 203 1 · mol⁻¹) are determined by titration of I₂ or KI₃ in the separated organic and aqueous layers with thiosulfate standard solution. Aspects of environmental protection are an integral part of the experiments,e.g. iodine and petroleum ether are recycled.