WorldWideScience

Sample records for aminoethanethiol

  1. Precursors to New Molecular Tube Ligands. 1. Double-Capped Trinuclear Cobalt Complexes of Aminoethanethiol.

    Science.gov (United States)

    Arnold, Alan P.; Bhula, Rajumati; Chen, Xiangna; Geue, Rodney J.; Jackson, W. Gregory

    1999-05-03

    Co(SCH(2)CH(2)NH(2))(3) has been capped on the facial amines through protection of the thiolates by coordination of two such complexes to a central Co(III) ion. The trinuclear species forming the framework is the complex ion [Co{Co(SCH(2)CH(2)NH(2))(3)}(2)](3+), 1, in meso and rac forms which have been chromatographically separated and identified. Hexaimine derivatives of 1, [Co{Co(SCH(2)CH(2)N=CH(2))(3)}(2)](3+), 2, have been synthesized in good yield by reaction with excess paraformaldehyde and base in CH(3)CN. The hexaimines have been reacted with NH(3) to yield dicapped aza species [Co{Co(SCH(2)CH(2)NHCH(2))(3)N}(2)](3+), 3, or reacted with nitromethane to yield the nitro-capped ions [Co{Co(SCH(2)CH(2)NHCH(2)C)(3)CNO(2)}(2)](3+), 4. The reactions are retentive; i.e., meso reactant yields meso product. All of the products have been characterized by (1)H NMR, (13)C NMR, and UV-vis spectroscopy. Electrochemical measurements (CV and dc coulometry) in CH(3)CN indicate that the central Co(III) ion in all of the species is reduced first, followed by the two terminal Co(III) centers. The formal potentials show that the Co(III) oxidation state is stabilized by the six thiolate bridging ligands in comparison to six thioether donor atoms, whereas capping has a destabilizing effect.

  2. A mild one-step process from graphene oxide and Cd2+ to a graphene-CdSe quantum dot nanocomposite with enhanced photoelectric properties.

    Science.gov (United States)

    Yu, Xiao-Yun; Chen, Zhao-He; Kuang, Dai-Bin; Su, Cheng-Yong

    2012-08-06

    Good connections: A graphene-CdSe quantum dot (QD) nanocomposite is prepared through a one-step hydrothermal method using graphene oxide (GO), Cd(CH(3)COO)(2), Na(2) SeSO(3), and aminoethanethiol (AET). The bifunctional AET acts not only as a covalent linker but also as a reductant to transform GO into graphene. The photoactive graphene-QD nanocomposite exhibits a significantly higher photocurrent compared to the QDs, GO or the graphene substrate under illumination. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Synthesis Of Some Novel Silver-Cysteamine Complexes

    Directory of Open Access Journals (Sweden)

    Davood Nematollahi

    2000-12-01

    Full Text Available The aim of this research was to synthesize some new silver-cysteamine complexes of potential biological interest. Reactions were carried out between silver nitrate and cysteamine (2-aminoethanethiol hydrochloride under different conditions of pH and mole ratios of the metal (silver to the ligand (cysteamine. Some novel silver-cysteamine complexes were made, and after characterization of the complexes by cyclic voltammetry, pH measurements, and microanalysis, it is now obvious that the mole ratio of the metal to the ligand in complexes is about four to three.

  4. Interfacial shear stress between single-walled carbon nanotubes and gold surfaces with and without an alkanethiol monolayer.

    Science.gov (United States)

    Pan, Huiyan; Wu, Yu-Chiao; Adams, George G; Miller, Glen P; McGruer, Nicol E

    2013-10-01

    A novel and effective technique is developed to make the first determination of shear stress between dielectrophoretically assembled single-walled carbon nanotubes (SWNTs) and surfaces. The results demonstrate that we can vary the shear stress by a factor of 20 by functionalizing a gold surface with different alkanethiols. The interfacial shear stress between a small bundle of SWNTs and a gold surface with and without self-assembled monolayers of alkanethiol (2-phenylethanethiol or 2-aminoethanethiol) is determined. The measurements are based on simple NEMS cantilever beams, a nanomanipulator, and a scanning electron microscope (SEM). It is emphasized that the measured quantity is the slack in the nanotube (not the shear stress) induced by the nanomanipulation. The shear stress is determined from the slack through a mechanics model. An average shear stress of 87 MPa between SWNTs and gold surfaces is obtained. For the tests on the self-assembled 2-aminoethanethiol surface, an average shear stress of 142 MPa is obtained. For the self-assembled 2-phenylethanethiol surface, the shear stress is determined to be around 7.2 MPa with an estimated work of adhesion of 0.5 J/m(2). Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Fabrication of a multilayer film electrode containing porphyrin and its application as a potentiometric sensor of iodide ion.

    Science.gov (United States)

    Sun, C; Zhao, J; Xu, H; Sun, Y; Zhang, X; Shen, J

    1998-05-01

    A novel iodide ion-selective electrode has been produced based on a molecular deposition technique in which water-soluble porphyrin was alternatively deposited with water-soluble polypyrrole on a 2-aminoethanethiol modified silver electrode. The potentiometric response is independent of pH of the solution between pH 1 and 7, while it is dependent on the nature of the medium. The electrode has a linear dynamic range between 1.6x10(-6) and 0.1 M with a Nernstian slope of 59 mV/decade and a detection limit of 1.0x10(-6) M in acetate buffer (0.1 M, pH 4.6). The electrode has the advantages of low resistance, short conditioning time and fast response.

  6. S-bridged complex of 99mTc with fac (S)-[Rh(aet)3]. Quality control, characterization and biodistribution studies in rats

    International Nuclear Information System (INIS)

    Amir, N.; Roohi, S.; Pervez, S.; Mushtaq, A.; Jehangir, M.; Miyashita, Y.; Okamoto, K.

    2009-01-01

    fac(S)-[Rh(aet) 3 ] (aet = 2-aminoethanethiolate) is N 3 S 3 metalloligand which can coordinate to transition metal ions to form S-bridged polynuclear complexes. The reaction was carried out between 99m TcO 4 Na and fac(S)-[Rh(aet) 3 ] in the presence of SnCl 2 x 2H 2 O. A complex analogous to [Re(Rh(aet 3 )) 2 ] 3+ is formed. A simple method for radiolabeling of fac(S)-[Rh(aet) 3 ] with 99m Tc has been developed and radiolabeling efficiency was higher than 99%. Effect of SnCl 2 x 2H 2 O concentration, electrophoresis, HPLC, UV-Visible absorption spectra and biodistribution studies in rats were performed. Higher uptake by kidneys showed rapid distribution of the labeled fac(S)-[Rh(aet) 3 ]. Liver uptake was significant, stomach, lungs and intestine uptake was high at 4 hours post injection time. (author)

  7. Polymer-Supported Optically Active fac(S)-Tris(thiotato)rhodium(III) Complex for Sulfur-Bridging Reaction With Precious Metal Ions.

    Science.gov (United States)

    Aizawa, Sen-Ichi; Tsubosaka, Soshi

    2016-01-01

    The optically active mixed-ligand fac(S)-tris(thiolato)rhodium(III) complexes, ΔL -fac(S)-[Rh(aet)2 (L-cys-N,S)](-) (aet = 2-aminoethanethiolate, L-cys = L-cysteinate) () and ΔLL -fac(S)-[Rh(aet)(L-cys-N,S)2 ](2-) were newly prepared by the equatorial preference of the carboxyl group in the coordinated L-cys ligand. The amide formation reaction of with 1,10-diaminodecane and polyallylamine gave the diamine-bridged dinuclear Rh(III) complex and the single-chain polymer-supported Rh(III) complex with retention of the ΔL configuration of , respectively. These Rh(III) complexes reacted with Co(III) or Co(II) to give the linear-type trinuclear structure with the S-bridged Co(III) center and the two Δ-Rh(III) terminal moieties. The polymer-supported Rh(III) complex was applied not only to the CD spectropolarimetric detection and determination of a trace of precious metal ions such as Au(III), Pt(II), and Pd(II) but also to concentration and extraction of these metal ions into the solid polymer phase. Chirality 28:85-91, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  8. Synthesis of novel poly(ethylene glycol) derivatives having pendant amino groups and aggregating behavior of its mixture with fatty acid in water.

    Science.gov (United States)

    Koyama, Y; Umehara, M; Mizuno, A; Itaba, M; Yasukouchi, T; Natsume, K; Suginaka, A

    1996-01-01

    Novel poly(ethylene glycol) (PEG) derivatives having pendant amino groups were prepared by copolymerization of allyl glycidyl ether with ethylene oxide followed by chemical modification of the double bond side chains. Dropwise addition of the mixture of monomers to the anionic initiator gave an almost monodisperse (Mw/Mn = 1.05) random copolymer. 1H NMR spectra showed that addition of 2-aminoethanethiol to the pendant allyl groups of the copolymer was completely carried out in methanol without catalyst, and an aminated PEG derivative with a definite structure was obtained. Acetylation of the pendant amino groups was readily performed by acetic anhydride with triethylamine. A gel permeation chromatogram of the acetylated polymer showed a very narrow molecular weight distribution (Mw/Mn = 1.06) of the polyamine. These cationic PEG derivatives make amphiphilic polyion complexes with fatty acids, and then aggregate in water. A fluorescence study using pyrene as a microenvironment probe revealed that the aminated PEG-lauric acid ion complex could take up the hydrophobic fluorescence probe into the lipophilic field inside, and they also had a critical aggregation concentration at [lauric acid] = 0.7 mM. It is much lower than the critical micelle concentration of the corresponding fatty acid sodium salts, indicating high stability of the polymer-fatty acid aggregate.

  9. Synthesis and functionalization of coiled carbon filaments

    Science.gov (United States)

    Hikita, Muneaki

    grown at the higher temperature had smaller fiber size and coil diameter, and longer lifetime of catalyst. For in-depth analysis, growth kinetics of CMCs were studied using an exponential decay model for catalyst poisoning. In the third study, CMCs were functionalized for improvement of water dispersion, optical properties and self-assembly. As-grown CMCs were hydrophobic. To improve water dispersion for biological applications, the surface of as-grown CMCs were oxidized by concentrated nitric acid at room temperature. After the oxidation, the acid-treated CMCs were well dispersed in water. For optical property, CMCs were functionalized with octadecylamine (ODA). Upon photoexcitation, the functionalized CMCs exhibited photoluminescence in the visible region. Similar to carbon based nanoparticles, the photoluminescence of CMCs was attributed to electron-hole radiative recombination after surface passivation. The results suggest that these functionalized CMCs might be used as a new class of optical agents for biological applications. As a primary experiment to study Au-S bonding, aminoethanethiol (HSCH2CH2NH2) was attached to the surface of gold-coated CMCs. Energy dispersive X-ray (EDX) mapping shows gold, sulfur and nitrogen on the surface of CMCs. Then, a thiol-modified ssDNA attachment experiment was performed using a similar functionalization procedure as aminoethanethiol. The existence of phosphorus, nitrogen, oxygen and sulfur on surface of Au-coated CMCs immersed in thiol-modified ssDNA solution was confirmed by the EDX spectrum. The result indicates that ssDNA was fixed on their surface. In the fourth study, the effect of oxidized CMCs on mouse embryonic stem (MES) cells was examined to determine their toxicity. Mouse embryonic stem cells represent a unique cell population with the ability to undergo both self-renewal and differentiation. Results indicate that oxidized CMCs had very little toxicity on stem cell viability. There was no observed loss of alkaline

  10. Understanding human thiol dioxygenase enzymes: structure to function, and biology to pathology.

    Science.gov (United States)

    Sarkar, Bibekananda; Kulharia, Mahesh; Mantha, Anil K

    2017-04-01

    Amino acid metabolism is a significant metabolic activity in humans, especially of sulphur-containing amino acids, methionine and cysteine (Cys). Cys is cytotoxic and neurotoxic in nature; hence, mammalian cells maintain a constant intracellular level of Cys. Metabolism of Cys is mainly regulated by two thiol dioxygenases: cysteine dioxygenase (CDO) and 2-aminoethanethiol dioxygenase (ADO). CDO and ADO are the only human thiol dioxygenases reported with a role in Cys metabolism and localized to mitochondria. This metabolic pathway is important in various human disorders, as it is responsible for the synthesis of antioxidant glutathione and is also for the synthesis of hypotaurine and taurine. CDO is the most extensively studied protein, whose high-resolution crystallographic structures have been solved. As compared to CDO, ADO is less studied, even though it has a key role in cysteamine metabolism. To further understand ADO's structure and function, the three-dimensional structures have been predicted from I-TASSER and SWISS-MODEL servers and validated with PROCHECK software. Structural superimposition approach using iPBA web server further confirmed near-identical structures (including active sites) for the predicted protein models of ADO as compared to CDO. In addition, protein-protein interaction and their association in patho-physiology are crucial in understanding protein functions. Both ADO and CDO interacting partner profiles have been presented using STRING database. In this study, we have predicted a 3D model structure for ADO and summarized the biological roles and the pathological consequences which are associated with the altered expression and functioning of ADO and CDO in case of cancer, neurodegenerative disorders and other human diseases. © 2017 The Authors. International Journal of Experimental Pathology © 2017 International Journal of Experimental Pathology.

  11. Rhemium-186-monoaminemonoamidedithiol-conjugated bisphosphonate derivatives for bone pain palliation

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Kazuma [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Advanced Science Research Center, Kanazawa University, Kanazawa 920-8640 (Japan); Mukai, Takahiro [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Graduate School of Pharmaceutical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582 (Japan); Arano, Yasushi [Graduate School of Pharmaceutical Sciences, Chiba University, Chuo-ku, Chiba 260-8675 (Japan); Otaka, Akira [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Ueda, Masashi [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Uehara, Tomoya [Graduate School of Pharmaceutical Sciences, Chiba University, Chuo-ku, Chiba 260-8675 (Japan); Magata, Yasuhiro [Photon Medical Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192 (Japan); Hashimoto, Kazuyuki [Japan Atomic Energy Research Institute, Tokai-mura, Ibaraki 319-1195 (Japan); Saji, Hideo [Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan)]. E-mail: hsaji@pharm.kyoto-u.ac.jp

    2006-05-15

    To develop a radiopharmaceutical for the palliation of painful bone metastases based on the concept of bifunctional radiopharmaceuticals, we synthesized a bisphosphonate derivative labeled with rhenium-186 ({sup 186}Re) that contains a hydroxyl group at the central carbon of its bisphosphonate structure, we attached a stable {sup 186}Re-MAMA chelate to the amino group of a 4-amino butylidene-bisphosphonate derivative [N-[2-[[4-[(4-hydroxy-4,4-diphosphonobutyl)amino]-4-oxobutyl] -2-thioethylamino]acetyl]-2-aminoethanethiolate] oxorhenium (V) ({sup 186}Re-MAMA-HBP) and we investigated the effect of a hydroxyl group at the central carbon of its bisphosphonate structure on affinity for hydroxyapatite and on biodistribution by conducting a comparative study with [N-[2-[[3-(3,3-diphosphonopropylcarbamoyl)propyl]-2-thioethylamino]acetyl] -2-a minoethanethiolate] oxorhenium (V) ({sup 186}Re-MAMA-BP). The precursor of {sup 186}Re-MAMA-HBP, trityl (Tr)-MAMA-HBP, was obtained by coupling a Tr-MAMA derivative to 4-amino-1-hydroxybutylidene-1,1-bisphosphonate. {sup 186}Re-MAMA-HBP was prepared by a reaction with {sup 186}ReO{sub 4} {sup -} and SnCl{sub 2} in citrate buffer after the deprotection of the Tr groups of Tr-MAMA-HBP. After reversed-phase high-performance liquid chromatography, {sup 186}Re-MAMA-HBP had a radiochemical purity of over 95%. Compared with {sup 186}Re-MAMA-BP, {sup 186}Re-MAMA-HBP showed a greater affinity for hydroxyapatite beads in vitro and accumulated a significantly higher level in the femur in vivo. Thus, the introduction of a hydroxyl group into {sup 186}Re complex-conjugated bisphosphonates would be effective in enhancing accumulation in bones. These findings provide useful information on the design of bone-seeking therapeutic radiopharmaceuticals.

  12. Preparation and animal studies of 99Tcm-TRODAT-1 as a dopamine transporter imaging agent

    International Nuclear Information System (INIS)

    Fang Ping; Wu Chunying; Chen Zhengping; Zhou Xiang; Wan Weixing; Ji Shuren

    1999-01-01

    Objective: To develop 99 Tc m labelled dopamine transporter (DAT) imaging agent 99 Tc m -(2β-[N,N'-bis(2-mercaptoethyl) ethylenediamin] methyl, 3β-(4-chlorophenyl) tropane (TRODAT-1) for evaluating changes of DAT in patients with Parkinson's disease. Methods: TRODAT-1 was synthesized from cocaine by stepwise reactions adding two aminoethanethiol units. Using SnCl 2 as reducing agent, and in the presence of Naglucoheptonate, 99 Tc m -TRODAT-1 was prepared. Animal studies have been performed in rats and normal monkeys. Results: The structure of TRODAT-1 was confirmed by IR, 1 HNMR and MS. Radiochemical purity of 99 Tc m -TRODAT-1 was over 90%, and stable for 24 h at room temperature. The partition coefficient in octanol and buffer was 132 and 154 at pH 7.0 and 7.4 respectively. Biodistribution displayed relatively low uptake in rat brain (0.28 and 0.12% ID/org at 2 min and 60 min post injection, respectively), but high uptake in liver (16.7% ID/organ at 60 min), steady uptake in kidney (maintained 3% ID/organ). The major radioactivity was excreted by hepatobiliary systems. The distribution in rat's brain showed that striatal uptake were 0.193, 0.189, 0.142 and 0.136% ID/g at 2, 30, 60 and 120 min, respectively. The ratios of striatal to cerebellar, striatal to hippocampal and striatal to cortical were 4.45 2.55 and 3.15 at 120 min post injection, respectively. Brain image studies in monkeys indicated that TRODAT was uptake and retained in the basal ganglia, where containing DAT abundantly. Ratio of regional brain uptakes of striatum/cerebellum was 1.56 as measured by SPECT imaging at 120 min. Conclusions: Above results showed the stable, neutral and lipophilic complex 99 Tc m -TRODAT-1 can cross the blood brain barrier, and be selectively concentrated by the striatal area, where containing DAT abundantly. High quality images of monkeys were also obtained. It suggested that 99 Tc m -TRODAT-1 may be a promising agent for clinical application

  13. Phosphopeptide Enrichment by Covalent Chromatography after Derivatization of Protein Digests Immobilized on Reversed-Phase Supports

    Science.gov (United States)

    Nika, Heinz; Nieves, Edward; Hawke, David H.; Angeletti, Ruth Hogue

    2013-01-01

    A rugged sample-preparation method for comprehensive affinity enrichment of phosphopeptides from protein digests has been developed. The method uses a series of chemical reactions to incorporate efficiently and specifically a thiol-functionalized affinity tag into the analyte by barium hydroxide catalyzed β-elimination with Michael addition using 2-aminoethanethiol as nucleophile and subsequent thiolation of the resulting amino group with sulfosuccinimidyl-2-(biotinamido) ethyl-1,3-dithiopropionate. Gentle oxidation of cysteine residues, followed by acetylation of α- and ε-amino groups before these reactions, ensured selectivity of reversible capture of the modified phosphopeptides by covalent chromatography on activated thiol sepharose. The use of C18 reversed-phase supports as a miniaturized reaction bed facilitated optimization of the individual modification steps for throughput and completeness of derivatization. Reagents were exchanged directly on the supports, eliminating sample transfer between the reaction steps and thus, allowing the immobilized analyte to be carried through the multistep reaction scheme with minimal sample loss. The use of this sample-preparation method for phosphopeptide enrichment was demonstrated with low-level amounts of in-gel-digested protein. As applied to tryptic digests of α-S1- and β-casein, the method enabled the enrichment and detection of the phosphorylated peptides contained in the mixture, including the tetraphosphorylated species of β-casein, which has escaped chemical procedures reported previously. The isolates proved highly suitable for mapping the sites of phosphorylation by collisionally induced dissociation. β-Elimination, with consecutive Michael addition, expanded the use of the solid-phase-based enrichment strategy to phosphothreonyl peptides and to phosphoseryl/phosphothreonyl peptides derived from proline-directed kinase substrates and to their O-sulfono- and O-linked β-N-acetylglucosamine (O