Synthesis and γ-radiolysis of 2′-deoxy-5-fluorouridine and 5-fluorouridine derivatives

Seventeen compounds having a variety of substituents at the 3- and 5′-positions of 2′-deoxy-5-fluorouridine (5-FUdR) and 5-fluorouridine (5-FUR) were synthesized, and their γ-radiolysis in aqueous solutions were studied. The compounds having thioureido (RNHCSNH, R  H, PhCH₂, acyl) and thiocarbonylamino (XCSNH, X  PhCH₂S, PhO) groups at the 3-position of 5-FUdR were efficiently cleaved to give 5-FUdR with high G values upon γ-irradiation of their aqueous solutions. The active species for these cleavage reactions were hydrated electron (e⁻ _aq), H^• and HO^•. However, the compounds having a dimethylsulfoxyimino group at 3-position of 5-FUdR and 5-FUR afforded 5-FUdR and 5-FUR only under the radiolysis conditions where e⁻ _aq becomes a principal active species. The compound having a 2-benzoylthiazoylthiocarbonylamino group at the 3-position of 5-FUdR showed the highest reactivity toward HO^.. The mechanisms of these γ-radiolysis reactions are discussed. The examination of anticellular activities of γ-irradiated compounds having a thiocarbonylamino group at the 3-position of 5-FUdR toward murine Sarcoma 180 cells revealed that these compounds may be utilized as a candidate for a radiation-induced drug (RID).     

Synthesis and Characterization of Spinel‐Type Gallia‐Alumina Solid Solutions

By precipitation with ammonia of ethanolic solutions containing the appropriate proportions of gallium and aluminium nitrate, following by calcination of the resulting gels at 773 K, mixed Ga₂O₃/Al₂O₃ oxides having Ga:Al ratios of 9:1, 4:1, 1:1, 1:4 and 1:9 were obtained. Powder X‐ray diffraction showed that these mixed metal oxides form a series of solid solutions having the spinel‐type structure; also shown by γ‐Al₂O₃ and γ‐Ga₂O₃. The specific surface area (determined by nitrogen adsorption at 77 K) was found to range from 160 m² g^?1 for the mixed oxide having Ga:Al = 9:1 up to 370 m² g^?1 for that having Ga:Al = 1:9. High resolution MAS NMR showed that Ga³⁺ and Al³⁺ ions occur at both tetrahedral and octahedral sites in the spinel‐type structure of the mixed metal oxides, although there is a preferential occupation of tetrahedral sites by Ga³⁺ ions. A proportion of penta‐coordinated Al³⁺ ions was also found. IR spectra of carbon monoxide adsorbed at 77 K showed that the mixed metal oxides have a considerable Lewis acidity, related mainly to tetrahedrally coordinated metal ions exposed at crystal surfaces. The characteristic infrared absorption band of coordinated (adsorbed) CO appears in the range 2205–2190 cm^?1, and its peak wavenumber is nearly independent of Ga:Al ratio in the mixed gallia‐alumina oxides.     

Esr studies on the reactive character of the radical anions,so−2, so−3 and so−4 in aqueous solution

The reactive characteristics of the oxy anion radicals of sulphur, SO^?₂, SO^?₃ and SO^?₄ were investigated by use of the rapid-mixing flow technique coupled with electron spin resonance (ESR) which can detect the radicals having a lifetime of 5–100 msec. The SO^?₂ reduced the aromatic nitro compounds to the corresponding anion radicals, but did not abstract the hydrogen from the saturated compounds nor add to the unsaturated compounds. The SO^?₃ could add to the compounds having CC bond, but did not abstract the hydrogen from the saturated compounds nor reduce the aromatic nitro compounds. The SO^?₄ could abstract the hydrogen from the saturated compounds and also add to the unsaturated compounds having CC bond, but did not reduce the aromatic nitro compounds. These differences of the reactivity towards the organic substrates were discussed on the basis of the difference in the distribution of the unpaired electron density of each radical anion.     

Kinetic-energy spectroscopy of high-rydberg fragments from keV collisions of H2+, D2+, N2+ and C2+ ions with rare-gas atoms

A method for measuring the kinetic-energy spectrum of high-Rydberg fragments from collisions of keV molecular ions with rare-gas atoms is described. The kinetic-energy spectra of high-Rydberg fragments from the collisions between D₂⁺, H₂⁺, N₂⁺ and C₂⁺ ions having 8 keV kinetic energy and thermal He and Xe are reported. Two single-collision processes for the generation of high-Rydberg fragments have been identified.     

Complex of cesium and rubidium fluorides with bromine trifluoride

Vibrational spectra are reported for the new complexes CsF·3BrF₃, RbF·3BrF₃, and RbF·2BrF₃ and the previously known complex CsF·2BrF₃. The spectra suggest that these compounds are salts having general formulas M⁺Br₃F^?₁₀ and M⁺Br₂F^?₇.     

Application of Anodic Stripping Differential Alternative Pulses Voltammetry for Simultaneous Species Quantification

The second order voltammetric technique Differential Alternative Pulses Voltammetry (DAPV) was applied in anodic stripping mode for simultaneous quantification of traces of species having close E_1/2. The potential‐time waveform and the signal processing allowing the DAPV application in stripping mode are presented. The pulses widths and amplitudes were optimized to obtain maximal sensitivity and resolution at traces of In³⁺ and Cd²⁺ (having E_1/2 difference of 45 mV) simultaneous quantification in presence of excess of Pb²⁺. Precise results for both species concentrations were obtained up to In³⁺ to Cd²⁺ concentration ratio as high as 1 to 10 without any sample pre‐treatment in purified industrial waste waters using 0.1 mol L⁻¹ HCl as supporting electrolyte.     

Amidocrownophanes as Anion Receptor

Crownophanes composed of 28-membered ring atoms having two hydroxy groups, two amide groups, and aromatic parts such as naphthalene rings and either pyridine or benzene ring, can bind anions with high affinity and selectivity. The anion-coordination ability of these species has been observed by ¹H NMR techniques. As anion guest molecules, we selected some halides, dihydrogenphosphate and acetate ions. It has been found that amidocrownophanes, 3 and 4, can recognize anions in the order;H₂PO ₄ ⁻ >F⁻>CH₃COO⁻>Cl⁻>>Br⁻ and I⁻, while not only 1, 2, and 5 having no hydroxy group but also 6 having 27-membered ring have no ability for anion recognition under the same conditions. In order to exhibit the recognition ability for anion receptor, plural amide groups, hydroxy groups, and m-phenylene or 1,6-pyridyl rigid part play an important role in this macrocyclic system.     

Two modes of asymmetric polymerization of phenylacetylenes having an L‐amino alcohol residue and two hydroxy groups

Four novel chiral phenylacetylenes having an L ‐amino alcohol residue and two hydroxymethyl groups were synthesized and polymerized by an achiral catalyst ((nbd)Rh⁺[η⁶‐(C₆H₅)B^?(C₆H₅)₃]) or a chiral catalytic system ([Rh(nbd)Cl]₂/(S)‐ or (R)‐phenylethylamine ((S)‐ or (R)‐PEA)). The two resulting polymers having an L ‐valinol or L ‐phenylalaninol residue showed Cotton effects at wavelengths around 430 nm. This observation indicated that they had an excess of one‐handed helical backbones. Positive and negative Cotton effects were observed only for the polymers having an L ‐valinol residue produced by using (R)‐ and (S)‐PEA as a cocatalyst, respectively, although the monomer had the same chirality. Even when the achiral catalyst was used, the two resulting polymers having an L ‐valinol or L ‐phenylalaninol residue showed Cotton effects despite the long distance between the chiral groups and the main chain. We have found the first example of a new type of chiral monomer, that is, a chiral phenylacetylene monomer having an L ‐amino alcohol residue and two hydroxy groups that was suitable for both modes of asymmetric polymerization, that is, the helix‐sense‐selective polymerization ( HSSP ) with the chiral catalytic system and the asymmetric‐induced polymerization ( AIP ) with the achiral catalyst. The other two monomers having L ‐alaninol and L ‐tyrosinol were found to be unsuitable to neither HSSP nor AIP because of their polymers' low solubility. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis of 4,4′-diaminotriphenylmethane derivatives using H3PW12O40 and HZSM5 zeolite under solvent-free conditions

An efficient and very simple method for synthesis of 4,4′-diaminotriphenylmethane and its derivatives has been achieved via reaction of various substituted aromatic aldehydes containing both electron-donating and electron-withdrawing groups with various anilines having electron-withdrawing and electron-donating groups in the presence of catalytic amounts of HZSM5 zeolite and H₃PW₁₂O₄₀ under solvent-free conditions. The reaction proceed with shorter reaction time and higher yield compared to the results obtained in different solvents. Anilines having electron-donating groups in comparison with those having electrondonating group performed this transformation in better yields. Also the results show that the steric hindrance plays an important role in this transformation. Reusability is an advantage of the HZSM5 zeolite, while it showed lesser activity than H₃PW₁₂O₄₀. The one-pot reaction, simple work up, high yields, use of efficient catalytic amount and eco-friendly reagents are the advantages of the proposed method. All products were characterized using ¹H NMR, ¹³C NMR and IR.     

Nonaqueous Liquid-Liquid Extraction. Extraction of Zinc from Methanol-Water Solution of Chloride by Trioctylphosph1Ne Oxide in Decaline

Abstract

The distribution of zinc was studied between the decaline phase having tri-n-octylphosphine oxide (TOPO) and the methanol-water phase (4:1 in molar ratio) having chloride ion, and the stability constants of zinc with chloride in the methanolic solution were calculated from the extraction experiments (K₁ = 2.4 × 10³, K₂ = 1.9 × 10²at 298°K).     

The use of model networks with reptating chains to study extraction efficiencies

It is possible to prepare “model” elastomeric networks having known values of the molecular weight M_c between crosslinks by endlinking functionally terminated polymer chains having number-average molecular weights M_n equal to the desired values of M_c. If chains having chemically inert groups at both ends are intentionally included during the preparation of such a system, they will remain unattached, merely reptating through the subsequently formed network structure. This technique was used to prepare a series of tetrafunctional polydimethylsiloxane (PDMS) networks having essentially the same degree of crosslinking (10^?3M_c = 11.3 g mol^?1) and constant amount of diluent in the form of unattached PDMS chains having molecular weights of 10^?3M_d = 26.4, 18.6, 15.8, 9.8, 6.7, 1.2, and 0.70 g mol^?1. Because of the very high mobility of PDMS, it was also possible to introduce essentially the same amount of the same diluents into already formed PDMS networks having the same M_c. Extractions carried out using tetrahydrofuran at room temperature showed that the diluent (“sol fraction”) introduced by swelling the network is more easily removed than that present during the endlinking, possibly because of less convoluted arrangements within the network structure. Chains with the largest values of M_d which were present during the endlinking were found to be very difficult to remove entirely. It is therefore extremely important to carry out exhaustive extractions to obtain reliable values of network sol fractions, particularly when such data are to be used to estimate extents of reaction in the preparation of end-linked elastomers.     

127I Mössbauer spectra for phenyliodonium ylides

¹²⁷I Mössbauer spectra for the phenyliodonium ylides were measured at 20 K. The valence electron populations (N_s, N_x-z) and the charge number (Z_I) for iodine atom are estimated from the Mössbauer parameters. The obtained populations were very close to those of diphenyliodonium chloride having two I-C primary bonds. To examine the possibility of some double bond character, the electron populations for the case of N_z = 1.90 are estimated. In this case, the Z_I values become larger as 1.2-1.3, and these values were unreasonably large because the values are close to those of PhICl₂, PhI(OAc)₂ having electron withdrawing ligands. Thereby, ¹²⁷I Mössbauer parameters suggest little double bond character for phenyliodonium ylides.     

Gas Permeability of Poly (organophosphazenes)

Abstract

The gas permeability and an oxygen to nitrogen selectivity was determined with some poly (organophosphazenes). It is found from the data that the membrance having the highest gas permeability was [NP(NHPrⁿ) (NHEt)]_n, and had 1.5x10^?6 cm^3. cm/cm³ sec.cmHg to oxgen or 2.2x10^?6cm³.cm/cm³.sec.cm.Hg to nitrogen. On the other hand, the membrance having the highest oxgen to nitrogen selectivity of about 3, had the formular of [NP(OC₆H₄Cl-p)₂]_n. Also, the selectivity does not depend on the glass transition temperature of the membrances. The membrance prepared from [NP(OC₆H₄CH₃-p)₂]_n has a negative activation energy to oxgen and nitrogen permeability.     

BATHOPRODUCTS and CONFORMERS OF ALL-trans-AND 13-ds BACTERIORHODOPSIN AT 90 K*

Abstract– At 90 K the photoproduct of the primary light reaction of (rani-bacteriorhodopsin, the bathoproduct K¹ consists of a mixture of at least three spectrally different species, K¹_I, K¹_II, and K¹_III having maxima in the difference absorption spectra at 645, 635 and 625 nm, respectively. The bathoproducts differ in their long wavelength absorption bands and in their rate constants for photo-conversion to trans-bacteriorhodopsin under far red light irradiation (λ > 720 nm). The bathoproducts are formed from different precursors–conformers of trans-bacteriorhodopsin, which are stable at 90 K, but are in equilibrium with each other at 213 K. We suggest that the bathoproducts may initiate parallel conversion cycles of trans-bacteriorhodopsin at low temperatures. The primary photoreaction of 13-cis-bacteriorhodopsin also yields three bathoproducts, K^c_I, K^c_II and K^c_III having maxima in the difference absorption spectra at 615, 605 and 595 nm, respectively.     

Na+ ion-specific binding and extraction by lipophilic armed cyclens via octadentate encapsulation

1,4,7,10-Tetraazacyclododecane derivatives having ester- and amide-functionalized sidearms predominantly extracted Na⁺ ion from an aqueous mixture of Li⁺, Na⁺ and K⁺ ions into a CH₂Cl₂ via specific octadentate complexation.     

Analytical energy gradient of high-spin multiplet state calculated by the SAC-CI method

A method of calculating analytical energy gradient of high-spin multiplet state by the SAC-CI (symmetry-adapted-cluster configuration-interaction) method is developed and implemented. This method is expected to be a powerful tool in studying the dynamics and properties of molecules having high spin-multiplicities. Good performance of this method is shown for the quartet states of BH⁺ and C₂⁺ and for the quintet states of C₂. The SAC-CI general-R method is also extended to the high-spin states, and proved to be useful especially for calculating accurate adiabatic excitation energies of the systems having quasi-degenerate orbital structure.     

Cobalt(II)-8-mercaptoquinolines complexing in cobalt(II) hexacyanoferrate(II) gelatin-immobilized matrix materials

Complexing processes between Co^II and 8-mercaptoquinoline, or its various alkyl- and aryl-substituted derivatives, in contact with Co₂[Fe(CN)₆]-gelatin-immobilized matrix materials, with aqueous solutions of corresponding ligands, have been studied. When R² = Me or Ph, formation of Co^II chelates having a 1:2 metal ion/singly deprotonated ligand is observed, whereas when R² = H, formation of Co^III chelates having metal ion/singly deprotonated ligand 1:3 ratios occur.     

Paramagnetic transition metal carbonyls : IV. ESR study of anions derived from (CO)5MnPbPh3 and (CO)4CoPbPh3 by high energy radiation

Exposure of (CO)₅MnPbPh₃ to ⁶⁰Co γ-ray at 77 K gave one major paramagnetic species detectable by ESR spectroscopy. This exhibited an anisotropic hyperfine interaction with ⁵⁵Mn, near free-spin g-values, and a small, almost isotropic coupling to ²⁰⁷Pb. The form of the A(⁵⁵Mn) and g-tensor components suggest an orbital of d_z² symmetry on manganese for the unpaired electron, but this cannot be directed along the MnPb bond since the ²⁰⁷Pb hyperfine coupling indicates a very low spin-density on lead. We suggest that the centre is formed by electron addition to manganese to give a formal d⁷ centre, with concomitant loss of one equatorial carbonyl ligand. We defind z as the direction of the lost ligand. A second centre, detected at high gain, having a large hyperfine coupling to ²⁰⁷Pb and a 31 G coupling to ⁵⁵Mn is tentatively identified as the parent cation.In marked contrast, the molecule (CO)₄CoPbPh₃ gave a single centre having comparable ⁵⁹Co hyperfine and g-tensor components, but also a very large hyperfine coupling to ²⁰⁷Pb (ca. 3300 G). Thus, in this case, an electron gain centre (d⁹) has been formed, the electron being accomodated in the highest MO having a large d_z² component on cobalt (z being now the CoPb direction).Reasons for the adoption of these different structures are discussed.     

Preparation of high surface area ZrO2 and ZrO2-Y2O3 from the alkoxide

In order to obtain a catalyst support with a high surface area, ZrO₂ and ZrO₂-Y₂O₃ were prepared by the hydrolytic decomposition of the corresponding isopropoxide dissolved in benzene. The hydrolysis was carried out at 80°C using an excess amount of distilled water in flowing dry nitrogen. The precipitates thus obtained were dried at 100°C followed by calcination at 500°C in air or nitrogen for 1 h. The specific surface areas for both of the ZrO₂ and ZrO₂-Y₂O₃ increased with increasing amount of water added for hydrolysis, and the surface areas for ZrO₂-Y₂O₃ increased with increasing yttrium content. A ZrO₂ having a surface area of 130 m²/g was produced, and a stabilized tetragonal ZrO₂ with 15 mol% Y³⁺ having a surface area of 200 m²/g was produced. Furthermore, despite the difference in the ZrO₂ and ZrO₂-Y₂O₃ crystal structures, the lattice-strain of ZrO₂ has been unequivocally related to the surface area.     

Investigations of TsVM zeolite acidities with different degrees of exchange of Na+ by H+

The method of programmed thermal desorption of ammonia has been used to establish that on the surface of the sodium form of type TsVM zeolite having a modulus SiO₂/Al₂O₃= 34.5 there are two types of acidic centers having ammonia desorption activation energies E_d equal to 40–45 and 80–100 kJ/mole. Replacement of Na⁺ by H⁺ leads to the appearance of a third type of center with a value E_D=130–150 kJ/mole. In this case in the IR spectra of specimens saturated with ammonia a band appears at 1410 cm_–1, which is evidence for the presence of NH ₄ ⁺ ions. Increasing the degree of Na⁺ replacement by H⁺ leads to a nonproportional rapid increase in the concentration of highly energetic centers, which may be explained by the partial transfer of aluminum into cationic positions with the formation of additional acidic centers.Translated from Teoreticheskie i Éksperimental'naya Khimiya, Vol. 22, No. 6, pp. 752–755, November–December, 1986.