- Synthesis, characterisation and speciation studies of heterobimetallic pyridinehydroxamate-bridged Pt(II)/M(II) complexes (M = Cu, Ni, Zn). Crystal structure of a novel heterobimetallic 3-pyridinehydroxamate-bridged Pt(II)/Cu(II) wave-like coordination polymer
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The reaction of cis-[Pt(NH3)2(3-pyhaH) 2]2+ (3-pyhaH = 3-pyridinehydroxamic acid) and cis-[Pt(NH3)2(4-pyhaH)2]2+ (4-pyhaH = 4-pyridinehydroxamic acid) with Cu(II), Ni(II) or Zn(II) in aqueous solution affords novel heterobimetallic pyridinehydroxamate-bridged complexes, {cis-[Pt(NH3)2(μ-3-pyha)M(μ-3-pyha)]·SO 4·xH2O}n and {cis-[Pt(NH 3)2-(μ-4-pyha)M(μ-4-pyha)]·SO 4·xH2O}n respectively. The crystal and molecular structure of one of these, {cis-[Pt-(NH3) 2(μ-3-pyha)Cu(μ-3-pyha)]SO4·8H 2O}n 3a, has been determined and was found to be a novel heterobimetallic wave-like coordination polymer, the structure of which contains interlinked pyridinehydroxamate-bridged repeating units of Pt(II) and Cu(II) ions in slightly distorted square-planar N4 and O4 coordination environments respectively and extensive hydrogen-bonding through the Pt ammines and the deprotonated hydroxamate O and via the O of the SO 42- counterions and the H(N) of the hydroxamate moiety. Spectrophotometric and speciation studies on the other heterobimetallic systems confirm that very similar species are being formed in solution and based on elemental analysis and spectroscopic results analogous complexes are formed in the solid-state. In this paper, we report the first examples of coordination polymers incorporating both Pt(II)/Cu(II), Pt(II)/Ni(II) and Pt(II)/Zn(II) and containing pyridinehydroxamic acids as bridging scaffolds. The Royal Society of Chemistry 2005.
- Mulcahy, Clodagh,Dolgushin, Fedor M.,Krot, Krystyna A.,Griffith, Darren,Marmion, Celine J.
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- Iron(III) tris(pyridinehydroxamate)s and related nickel(II) and zinc(II) complexes: Potential platforms for the design of novel heterodimetallic supramolecular assemblies
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The reaction of 3- and 4-pyhaH (pyhaH = pyridinehydroxamic acid) with hydrated metal salts (FeIII, NiII, ZnII) in aqueous solution affords tris(pyridinehydroxamate)s in the case of Fe III and bis(pyridinehydroxamate)s in the case of ZnII and NiII in both the solid state and in solution. These metal pyridinehydroxamates that have the hydroxamato moiety coordinated in an O,O′-bidentate fashion all contain free pyridine nitrogen donor atoms that might allow them to be used as building blocks in the construction of pyridinehydroxamato-bridged supramolecular assemblies. The crystal and molecular structures of the two novel FeIII tris(pyridinehydroxamate) building blocks [FeIII(3-pyha)3]·5.125H2O (1a) and [FeIII(4-pyha)3]·5.5H2O (2a) are found to have different packing systems despite the similar nature of the two complexes. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Mulcahy, Clodagh,Krot, Krystyna A.,Griffith, Darren M.,Suponitsky, Kyrill Yu.,Starikova, Zoya A.,Marmion, Celine J.
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- Pentacyanoferrate(II) complex of pyridine-4- and pyrazine-2-hydroxamic acid as source of HNO: investigation of anti-tubercular and vasodilation activities
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A pharmacophore design approach, based on the coordination chemistry of an intimate molecular hybrid of active metabolites of pro-drugs, known to release active species upon enzymatic oxidative activation, is devised. This is exemplified by combining two anti-mycobacterial drugs: pyrazinamide (first line) and delamanid (third line) whose active metabolites are pyrazinoic acid (PyzCOOH) and likely nitroxyl (HNO (or NO.)), respectively. Aiming to generate those active species, a hybrid compound was envisaged by coordination of pyrazine-2-hydroxamic acid (PyzCONHOH) with a Na3[FeII(CN)5] moiety. The corresponding pentacyanoferrate(II) complex Na4[FeII(CN)5(PyzCONHO?)] was synthesized and characterized by several spectroscopic techniques, cyclic voltammetry, and DFT calculations. Chemical oxidation of this complex with H2O2 was shown to induce the release of the metabolite PyzCOOH, without the need of the Mycobacterium tuberculosis (Mtb) pyrazinamidase enzyme (PncA). Control experiments show that both H2O2- and N-coordinated pyrazine FeII species are required, ruling out a direct hydrolysis of the hydroxamic acid or an alternative oxidative route through chelation of a metal center by a hydroxamic group. The release of HNO was observed using EPR spectroscopy in the presence of a spin trapping agent. The devised iron metal complex of pyrazine-2-hydroxamic acid was found inactive against an actively growing/non-resistant Mtb strain; however, it showed a strong dose-dependent and reversible vasodilatory activity with mostly lesser toxic effects than the reference drug sodium nitroprussiate, unveiling thus a potential indication for acute or chronic cardiovascular pathology. This is a priori a further indirect evidence of HNO release from this metal complex, standing as a possible pharmacophore model for an alternative vasodilator drug.
- Abbadi, Bruno Lopes,Bernardes-Génisson, Vania,Bizarro, Cristiano Valim,Carvalho, Edinilton Muniz,Chauvin, Remi,Ferreira, Talles Luann Abrantes,Lopes, Luiz Gonzaga Fran?a,Macchi, Fernanda Souza,Saquet, Alix Sournia,Sousa, Eduardo Henrique Silva,de Freitas Paulo, Tercio,de Morais Campos, Rafael,do Nascimento, Nilberto Robson Falc?o
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- Photoinduced one-pot synthesis of hydroxamic acids from aldehydes through in-situ generated silver nanoclusters
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Hydroxamic acids have attracted significant attention due to their widespread use in applied chemistry. In this report, a modified Angeli–Rimini method has been achieved via the visible light-mediated catalytic transformation of a variety of heterocyclic, aromatic and aliphatic aldehydes 1a–j to their corresponding hydroxamic acids 2a–j in 81–93% yield. The unique ability of vitamin K3 as a photoredox catalyst to expedite the development of completely new reaction mechanisms and to enable the construction of challenging carbon–nitrogen bonds has been investigated. It is shown for the first time that the vitamin K3 and aldehyde are largely responsible for rapid in situ reduction of Ag+ ions to catalytic photoluminescent Ag nanoclusters that possess a bandgap energy of 2.87?eV and are less than 2 nm in size. A mechanism for this reaction has been proposed and is supported by UV–Vis, TEM, ESI/MS, FT-IR, 1H NMR and 13C NMR analyses. The investigated method utilizes readily available reagents and produces the hydroxamic acids in high yields without the formation of side products, making it simple, practical and cost-effective.
- Mohamed, Yasser M. A.,Attia, Yasser A.,Solum, Eirik Johansson
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p. 7173 - 7186
(2018/08/17)
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- One-pot synthesis of primary amines from carboxylic acids through rearrangement of in situ generated hydroxamic acid derivatives
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A one-pot synthesis of primary amines from carboxylic acids through a Lossen rearrangement of hydroxamic acid derivatives, which were in situ generated by the reaction of carboxylic acids with O-trimethylsilylhydroxylamine (NH2OTMS) and carbonyl diimidazole (CDI, 1.5 equiv) in dimethyl sulfoxide at room temperature, has been achieved. This one-pot method could be applied to various carboxylic acids such as aromatic, heteroaromatic, aliphatic, and optically active substrates.
- Hoshino, Yujiro,Ohtsuka, Naoya,Okada, Takuya,Honda, Kiyoshi
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supporting information
p. 5304 - 5307
(2016/11/16)
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- SELECTIVE PLACEMENT OF CARBON NANOTUBES VIA COULOMBIC ATTRACTION OF OPPOSITELY CHARGED CARBON NANOTUBES AND SELF-ASSEMBLED MONOLAYERS
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A method of forming a structure having selectively placed carbon nanotubes, a method of making charged carbon nanotubes, a bi-functional precursor, and a structure having a high density carbon nanotube layer with minimal bundling. Carbon nanotubes are selectively placed on a substrate having two regions. The first region has an isoelectric point exceeding the second region's isoelectric point. The substrate is immersed in a solution of a bi-functional precursor having anchoring and charged ends. The anchoring end bonds to the first region to form a self-assembled monolayer having a charged end. The substrate with charged monolayer is immersed in a solution of carbon nanotubes having an opposite charge to form a carbon nanotube layer on the self-assembled monolayer. The charged carbon nanotubes are made by functionalization or coating with an ionic surfactant.
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Paragraph 0056
(2016/06/06)
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- Lossen rearrangements under heck reaction conditions
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The classical Lossen rearrangement converts activated hydroxamic acids to isocyanates that form numerous products upon their reaction with nucleophiles. We report a simple and highly efficient method of using Heck reaction conditions to initiate Lossen rearrangements of hydroxamic acids. In addition, Lossen rearrangements occur in the presence of palladium(II) acetate or triethylamine, components of the Heck reaction, alone. A potential mechanism is provided to explain this reactivity and these results show that Heck reactions and Lossen rearrangements occur under the same conditions and may provide new methods for facile initiation of Lossen rearrangements.
- AbdelHafez, El-Shimaa M.N.,Aly, Omar M.,Abuo-Rahma, Gamal El-Din A.A.,King, S. Bruce
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supporting information
p. 3456 - 3464
(2015/02/05)
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- SELECTIVE PLACEMENT OF CARBON NANOTUBES VIA COULOMBIC ATTRACTION OF OPPOSITELY CHARGED CARBON NANOTUBES AND SELF-ASSEMBLED MONOLAYERS
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A method of forming a structure having selectively placed carbon nanotubes, a method of making charged carbon nanotubes, a bi-functional precursor, and a structure having a high density carbon nanotube layer with minimal bundling. Carbon nanotubes are selectively placed on a substrate having two regions. The first region has an isoelectric point exceeding the second region's isoelectric point. The substrate is immersed in a solution of a bi-functional precursor having anchoring and charged ends. The anchoring end bonds to the first region to form a self-assembled monolayer having a charged end. The substrate with charged monolayer is immersed in a solution of carbon nanotubes having an opposite charge to form a carbon nanotube layer on the self-assembled monolayer. The charged carbon nanotubes are made by functionalization or coating with an ionic surfactant.
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(2013/04/13)
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- HISTONE DEACETYLASE INHIBITORS AND METHODS OF USE THEREOF
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The present invention provides novel compounds for inhibiting histone deacetylases, and pharmaceutically acceptable salts and derivatives thereof. The present invention further provides methods for treating disorders regulated by histone deacetylase activity (e.g., proliferative diseases, cancer, inflammatory diseases, protozoal infections, hair loss, etc.) comprising administering a therapeutically effective amount of a compound of the invention to a subject in need thereof. The present invention also provides methods for preparing compounds of the invention.
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Page/Page column 46
(2012/09/10)
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- Convenient synthesis of a library of discrete hydroxamic acids using the hydroxythiophenol (Marshall) resin
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Several resins have reportedly been used to synthesize hydroxamic acids except for the hydroxythiophenol (Marshall) resin. Herein, we report the use of the Marshall resin to synthesize hydroxamic acids from carboxylic acids and its application to convert a library of 14 discrete aliphatic and aromatic carboxylic acids including N-protected amino acids to their corresponding hydroxamic acids in good yields.
- Choi, Jinil,Park, Jewn Giew,Pang, Yuan-Ping
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p. 1103 - 1106
(2008/09/17)
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- Hydroxamic acid and its derivatives as inhibitors of melanocyte tyrosinase for topical skin lighteners
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Methods, compounds, and formulations are provided to reduce pigmentation in mammalian skin, comprising hydroxamic acid and its derivatives, and especially benzohydroxamic acid and its derivatives. The compounds preferably inhibit pigment synthesis in melanocytes through inhibition of melanocyte tyrosinase. The methods can be used for lightening skin, and for treating uneven skin complexions, which result from hyperpigmentation-related medical conditions such as melasma, age spots, freckles, ochronosis, and lentigo. The compounds can be used medically or cosmetically, and preferably as topical formulations.
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- NOUVEAUX DECONTAMINANTS. DESTRUCTION DU PARAOXON ET D'UN SIMILI DE L'YPERITE PAR QUELQUES ACIDES HYDROXAMIQUES
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A new series of hydroxamic acids 1-4 has been used in the destruction of paraoxon (O,O-diethyl O-paranitrophenylphosphate) and a mustard-related compound (2-chloro 2'-phenyl diethylsulfide).These hydroxamic acids are N-alkyl substituted isonicotinhydroxamic acid 1, and quinolone derivatives 2 norbornyl- and adamantylhydroxamic acids 3 and 4.The latter are very reactive and the addition of certain surfactants enhances the rate of the reaction.Very short half-lives are obtained with these compounds.
- Lion, C.,Hedayatullah, M.,Bauer, P.,Boukou-Poba, J. P.,Charvy, C.,et al.
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p. 617 - 621
(2007/10/02)
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- Cephalosporin antibiotics
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Cephalosporin antibiotics represented by the formula STR1 wherein R is hydrogen, C1 -C4 alkyl or a carboxy substituted alkyl group; R1 is H or C1 -C4 alkyl; n is 0, 1 or 2; and A and A' independently are hydrogen, C1 -C4 alkyl or allyl; and pharmaceutically acceptable salts thereof are broad spectrum antibiotics useful in the treatment of gram positive and gram negative infections of mammals.
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