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Klika KD, Da Pieve C, Kopka K, Smith G, Makarem A. Synthesis and application of a thiol-reactive HBED-type chelator for development of easy-to-produce Ga-radiopharmaceutical kits and imaging probes. Org Biomol Chem 2021; 19:1722-1726. [PMID: 33527964 DOI: 10.1039/d0ob02513e] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In radiopharmaceutical syntheses, maleimide is commonly used for linking thiol-bearing bioactive molecules to metal-complexing ligands (chelators). However, due to instability of the resulting linkage, phenyloxadiazolyl methylsulfone (PODS) was developed as an alternative to maleimide. This coupling strategy has never been attempted with HBED which is a powerful chelator for gallium-radiolabeling especially at ambient temperature. Here we present HBED-CC-PODS as a bifunctional chelator scaffold for the site-selective conjugation of thiol-bearing vectors and [68Ga]Ga-radiolabeling.
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Affiliation(s)
- Karel D Klika
- German Cancer Research Center (DKFZ), Molecular Structure Analysis, INF 280, 69120 Heidelberg, Germany
| | - Chiara Da Pieve
- The Institute of Cancer Research, Division of Radiotherapy and Imaging, 123 Old Brompton Road, London SW7 3RP, UK
| | - Klaus Kopka
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Graham Smith
- The Institute of Cancer Research, Division of Radiotherapy and Imaging, 123 Old Brompton Road, London SW7 3RP, UK
| | - Ata Makarem
- German Cancer Research Center (DKFZ), Division of Radiopharmaceutical Chemistry, INF 280, 69120 Heidelberg, Germany
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2
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Abstract
Radiometals possess an exceptional breadth of decay properties and have been applied to medicine with great success for several decades. The majority of current clinical use involves diagnostic procedures, which use either positron-emission tomography (PET) or single-photon imaging to detect anatomic abnormalities that are difficult to visualize using conventional imaging techniques (e.g., MRI and X-ray). The potential of therapeutic radiometals has more recently been realized and relies on ionizing radiation to induce irreversible DNA damage, resulting in cell death. In both cases, radiopharmaceutical development has been largely geared toward the field of oncology; thus, selective tumor targeting is often essential for efficacious drug use. To this end, the rational design of four-component radiopharmaceuticals has become popularized. This Review introduces fundamental concepts of drug design and applications, with particular emphasis on bifunctional chelators (BFCs), which ensure secure consolidation of the radiometal and targeting vector and are integral for optimal drug performance. Also presented are detailed accounts of production, chelation chemistry, and biological use of selected main group and rare earth radiometals.
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Affiliation(s)
- Thomas I Kostelnik
- Medicinal Inorganic Chemistry Group, Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Chris Orvig
- Medicinal Inorganic Chemistry Group, Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
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3
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Sattarzadeh E, Amini MM, Kakaei S, Khanchi A. 68Ga-radiolabeled magnetic nanoparticles for PET–MRI imaging. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-6003-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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4
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Price TW, Greenman J, Stasiuk GJ. Current advances in ligand design for inorganic positron emission tomography tracers 68Ga, 64Cu, 89Zr and 44Sc. Dalton Trans 2018; 45:15702-15724. [PMID: 26865360 DOI: 10.1039/c5dt04706d] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A key part of the development of metal based Positron Emission Tomography probes is the chelation of the radiometal. In this review the recent developments in the chelation of four positron emitting radiometals, 68Ga, 64Cu, 89Zr and 44Sc, are explored. The factors that effect the chelation of each radio metal and the ideal ligand system will be discussed with regards to high in vivo stability, complexation conditions, conjugation to targeting motifs and complexation kinetics. A series of cyclic, cross-bridged and acyclic ligands will be discussed, such as CP256 which forms stable complexes with 68Ga under mild conditions and PCB-TE2A which has been shown to form a highly stable complex with 64Cu. 89Zr and 44Sc have seen significant development in recent years with a number of chelates being applied to each metal - eight coordinate di-macrocyclic terephthalamide ligands were found to rapidly produce more stable complexes with 89Zr than the widely used DFO.
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Affiliation(s)
- Thomas W Price
- School of Biological, Biomedical and Environmental Sciences, The University of Hull, HU6 7RX, UK. and Positron Emission Tomography Research Centre, The University of Hull, HU6 7RX, UK
| | - John Greenman
- School of Biological, Biomedical and Environmental Sciences, The University of Hull, HU6 7RX, UK.
| | - Graeme J Stasiuk
- School of Biological, Biomedical and Environmental Sciences, The University of Hull, HU6 7RX, UK. and Positron Emission Tomography Research Centre, The University of Hull, HU6 7RX, UK
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5
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Burke BP, Baghdadi N, Kownacka AE, Nigam S, Clemente GS, Al-Yassiry MM, Domarkas J, Lorch M, Pickles M, Gibbs P, Tripier R, Cawthorne C, Archibald SJ. Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions. NANOSCALE 2015; 7:14889-14896. [PMID: 26292197 DOI: 10.1039/c5nr02753e] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging.
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Affiliation(s)
- Benjamin P Burke
- Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
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Burke BP, Baghdadi N, Clemente GS, Camus N, Guillou A, Kownacka AE, Domarkas J, Halime Z, Tripier R, Archibald SJ. Final step gallium-68 radiolabelling of silica-coated iron oxide nanorods as potential PET/MR multimodal imaging agents. Faraday Discuss 2015; 175:59-71. [PMID: 25325197 DOI: 10.1039/c4fd00137k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The investigation of iron oxide-based positron emission tomography/magnetic resonance (PET/MR) multimodal imaging agents is an expanding field in which a variety of nanoparticle sizes, shapes, surface coatings and radioisotopes are open for exploration. This study develops iron oxide nanorods which are coated with various mixtures of poly(ethylene glycol) (PEG) and macrocyclic ligand (DO3A) via the formation of a silica layer on the surface. Gallium-68 radiolabelling of the nanorods was carried out in high radiochemical yields (RCY) and their stability in human serum was demonstrated for all constructs, even in the absence of the macrocyclic chelating unit. Further studies were carried out in an attempt to determine the appropriate amount of PEG coating to give optimal properties for future in vivo studies.
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Affiliation(s)
- Benjamin P Burke
- Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
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Gregório T, Rüdiger AL, Nunes GG, Soares JF, Hughes DL. Crystal structure of an eight-coordinate terbium(III) ion chelated by N,N'-bis-(2-hy-droxy-benz-yl)-N,N'-bis-(pyridin-2-ylmeth-yl)ethyl-enedi-amine (bbpen(2-)) and nitrate. Acta Crystallogr E Crystallogr Commun 2015; 71:65-8. [PMID: 25705453 PMCID: PMC4331920 DOI: 10.1107/s2056989014026826] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 12/05/2014] [Indexed: 11/25/2022]
Abstract
The reaction of terbium(III) nitrate penta-hydrate in aceto-nitrile with N,N'-bis-(2-hy-droxy-benz-yl)-N,N'-bis-(pyridin-2-ylmeth-yl)ethyl-enedi-amine (H2bbpen), previously deprotonated with tri-ethyl-amine, produced the mononuclear compound [N,N'-bis-(2-oxidobenzyl-κO)-N,N'-bis-(pyridin-2-ylmethyl-κN)ethylenedi-amine-κ(2) N,N'](nitrato-κ(2) O,O')terbium(III), [Tb(C28H28N4O2)(NO3)]. The mol-ecule lies on a twofold rotation axis and the Tb(III) ion is eight-coordinate with a slightly distorted dodeca-hedral coordination geometry. In the symmetry-unique part of the mol-ecule, the pyridine and benzene rings are both essentially planar and form a dihedral angle of 61.42 (7)°. In the mol-ecular structure, the N4O4 coordination environment is defined by the hexa-dentate bbpen ligand and the bidentate nitrate anion. In the crystal, a weak C-H⋯O hydrogen bond links mol-ecules into a two-dimensional network parallel to (001).
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Affiliation(s)
- Thaiane Gregório
- Departamento de Química, Universidade Federal do Paraná, Centro Politécnico, Jardim das Américas, 81530-900 Curitiba-PR, Brazil
| | - André Luis Rüdiger
- Departamento de Química, Universidade Federal do Paraná, Centro Politécnico, Jardim das Américas, 81530-900 Curitiba-PR, Brazil
| | - Giovana G. Nunes
- Departamento de Química, Universidade Federal do Paraná, Centro Politécnico, Jardim das Américas, 81530-900 Curitiba-PR, Brazil
| | - Jaísa F. Soares
- Departamento de Química, Universidade Federal do Paraná, Centro Politécnico, Jardim das Américas, 81530-900 Curitiba-PR, Brazil
| | - David L. Hughes
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, England
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Sharma V, Sivapackiam J, Harpstrite SE, Prior JL, Gu H, Rath NP, Piwnica-Worms D. A generator-produced gallium-68 radiopharmaceutical for PET imaging of myocardial perfusion. PLoS One 2014; 9:e109361. [PMID: 25353349 PMCID: PMC4212944 DOI: 10.1371/journal.pone.0109361] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 08/31/2014] [Indexed: 11/19/2022] Open
Abstract
Lipophilic cationic technetium-99m-complexes are widely used for myocardial perfusion imaging (MPI). However, inherent uncertainties in the supply chain of molybdenum-99, the parent isotope required for manufacturing 99Mo/99mTc generators, intensifies the need for discovery of novel MPI agents incorporating alternative radionuclides. Recently, germanium/gallium (Ge/Ga) generators capable of producing high quality 68Ga, an isotope with excellent emission characteristics for clinical PET imaging, have emerged. Herein, we report a novel 68Ga-complex identified through mechanism-based cell screening that holds promise as a generator-produced radiopharmaceutical for PET MPI.
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Affiliation(s)
- Vijay Sharma
- BRIGHT Institute, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail: (VS); (DPW)
| | - Jothilingam Sivapackiam
- BRIGHT Institute, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Scott E. Harpstrite
- BRIGHT Institute, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Julie L. Prior
- BRIGHT Institute, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Hannah Gu
- BRIGHT Institute, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Nigam P. Rath
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, Missouri, United States of America
| | - David Piwnica-Worms
- BRIGHT Institute, Molecular Imaging Center, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Departments of Cell Biology and Physiology and Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail: (VS); (DPW)
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9
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Burke BP, Clemente GS, Archibald SJ. Recent advances in chelator design and labelling methodology for (68) Ga radiopharmaceuticals. J Labelled Comp Radiopharm 2014; 57:239-43. [PMID: 24497011 DOI: 10.1002/jlcr.3146] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 10/29/2013] [Indexed: 12/28/2022]
Abstract
Gallium-68 has the potential to become the technetium-99m of positron emission tomography with ideal decay characteristics and a long-lived parent isotope for generator production. The work in the area of (68) Ga is focused on two key areas: (1) synthesis of a library of bifunctional chelators, which can be quickly radiolabelled to form kinetically inert complexes under mild conditions compatible with biomolecules and (2) development of radiosynthetic methodologies for clinical use and to facilitate radiolabelling of a wide range of chelators under mild conditions. Recent advances in these areas, with particular focus on the past 3 years, are covered herein.
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Affiliation(s)
- Benjamin P Burke
- Department of Chemistry, University of Hull, Hull, HU6 7RX, UK; Positron Emission Tomography Research Centre, University of Hull, Hull, HU6 7RX, UK
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10
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Abstract
Radiometals comprise many useful radioactive isotopes of various metallic elements. When properly harnessed, these have valuable emission properties that can be used for diagnostic imaging techniques, such as single photon emission computed tomography (SPECT, e.g.(67)Ga, (99m)Tc, (111)In, (177)Lu) and positron emission tomography (PET, e.g.(68)Ga, (64)Cu, (44)Sc, (86)Y, (89)Zr), as well as therapeutic applications (e.g.(47)Sc, (114m)In, (177)Lu, (90)Y, (212/213)Bi, (212)Pb, (225)Ac, (186/188)Re). A fundamental critical component of a radiometal-based radiopharmaceutical is the chelator, the ligand system that binds the radiometal ion in a tight stable coordination complex so that it can be properly directed to a desirable molecular target in vivo. This article is a guide for selecting the optimal match between chelator and radiometal for use in these systems. The article briefly introduces a selection of relevant and high impact radiometals, and their potential utility to the fields of radiochemistry, nuclear medicine, and molecular imaging. A description of radiometal-based radiopharmaceuticals is provided, and several key design considerations are discussed. The experimental methods by which chelators are assessed for their suitability with a variety of radiometal ions is explained, and a large selection of the most common and most promising chelators are evaluated and discussed for their potential use with a variety of radiometals. Comprehensive tables have been assembled to provide a convenient and accessible overview of the field of radiometal chelating agents.
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Affiliation(s)
- Eric W Price
- Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, CanadaV6T 1Z1.
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11
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Bartholomä MD. Recent developments in the design of bifunctional chelators for metal-based radiopharmaceuticals used in Positron Emission Tomography. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2012.01.061] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Wadas TJ, Wong EH, Weisman GR, Anderson CJ. Coordinating radiometals of copper, gallium, indium, yttrium, and zirconium for PET and SPECT imaging of disease. Chem Rev 2010; 110:2858-902. [PMID: 20415480 PMCID: PMC2874951 DOI: 10.1021/cr900325h] [Citation(s) in RCA: 681] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Thaddeus J Wadas
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S. Kingshighway Blvd., Campus Box 8225 St. Louis, Missouri 63110, USA.
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14
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Bartholomä MD, Louie AS, Valliant JF, Zubieta J. Technetium and Gallium Derived Radiopharmaceuticals: Comparing and Contrasting the Chemistry of Two Important Radiometals for the Molecular Imaging Era. Chem Rev 2010; 110:2903-20. [DOI: 10.1021/cr1000755] [Citation(s) in RCA: 250] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Mark D. Bartholomä
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, and Department of Chemistry, McMaster University, Hamilton, Canada ON L8S 4M1
| | - Anika S. Louie
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, and Department of Chemistry, McMaster University, Hamilton, Canada ON L8S 4M1
| | - John F. Valliant
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, and Department of Chemistry, McMaster University, Hamilton, Canada ON L8S 4M1
| | - Jon Zubieta
- Department of Chemistry, Syracuse University, Syracuse, New York 13244, and Department of Chemistry, McMaster University, Hamilton, Canada ON L8S 4M1
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Liu S. Bifunctional coupling agents for radiolabeling of biomolecules and target-specific delivery of metallic radionuclides. Adv Drug Deliv Rev 2008; 60:1347-70. [PMID: 18538888 PMCID: PMC2539110 DOI: 10.1016/j.addr.2008.04.006] [Citation(s) in RCA: 299] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 04/16/2008] [Indexed: 11/23/2022]
Abstract
Receptor-based radiopharmaceuticals are of great current interest in molecular imaging and radiotherapy of cancers, and provide a unique tool for target-specific delivery of radionuclides to the diseased tissues. In general, a target-specific radiopharmaceutical can be divided into four parts: targeting biomolecule (BM), pharmacokinetic modifying (PKM) linker, bifunctional coupling or chelating agent (BFC), and radionuclide. The targeting biomolecule serves as a "carrier" for specific delivery of the radionuclide. PKM linkers are used to modify radiotracer excretion kinetics. BFC is needed for radiolabeling of biomolecules with a metallic radionuclide. Different radiometals have significant difference in their coordination chemistry, and require BFCs with different donor atoms and chelator frameworks. Since the radiometal chelate can have a significant impact on physical and biological properties of the target-specific radiopharmaceutical, its excretion kinetics can be altered by modifying the coordination environment with various chelators or coligand, if needed. This review will focus on the design of BFCs and their coordination chemistry with technetium, copper, gallium, indium, yttrium and lanthanide radiometals.
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Affiliation(s)
- Shuang Liu
- School of Health Sciences, Purdue University, West Lafayette, USA.
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16
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Boghaei DM, Gharagozlou M. Spectral characterization of novel ternary zinc(II) complexes containing 1,10-phenanthroline and Schiff bases derived from amino acids and salicylaldehyde-5-sulfonates. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 67:944-9. [PMID: 17049913 DOI: 10.1016/j.saa.2006.09.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2006] [Revised: 09/02/2006] [Accepted: 09/11/2006] [Indexed: 05/12/2023]
Abstract
A series of new ternary zinc(II) complexes [Zn(L(1-10))(phen)], where phen is 1,10-phenanthroline and H(2)L(1-10)=tridentate Schiff base ligands derived from the condensation of amino acids (glycine, l-phenylalanine, l-valine, l-alanine, and l-leucine) and salicylaldehyde-5-sulfonates (sodium salicylaldehyde-5-sulfonate and sodium 3-methoxy-salicylaldehyde-5-sulfonate), have been synthesized. The complexes were characterized by elemental analysis, IR, UV-vis, (1)H NMR, and (13)C NMR spectra. The IR spectra of the complexes showed large differences between nu(as)(COO) and nu(s)(COO), Deltanu (nu(as)(COO)-nu(s)(COO)) of 191-225 cm(-1), indicating a monodentate coordination of the carboxylate group. Spectral data showed that in these ternary complexes the zinc atom is coordinated with the Schiff base ligand acts as a tridentate ONO moiety, coordinating to the metal through its phenolic oxygen, imine nitrogen, and carboxyl oxygen, and also with the neutral planar chelating ligand, 1,10-phenanthroline, coordinating through nitrogens.
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Affiliation(s)
- Davar M Boghaei
- Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran, Iran.
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17
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Storr T, Merkel M, Song-Zhao GX, Scott LE, Green DE, Bowen ML, Thompson KH, Patrick BO, Schugar HJ, Orvig C. Synthesis, Characterization, and Metal Coordinating Ability of Multifunctional Carbohydrate-Containing Compounds for Alzheimer's Therapy. J Am Chem Soc 2007; 129:7453-63. [PMID: 17511455 DOI: 10.1021/ja068965r] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Dysfunctional interactions of metal ions, especially Cu, Zn, and Fe, with the amyloid-beta (A beta) peptide are hypothesized to play an important role in the etiology of Alzheimer's disease (AD). In addition to direct effects on A beta aggregation, both Cu and Fe catalyze the generation of reactive oxygen species (ROS) in the brain further contributing to neurodegeneration. Disruption of these aberrant metal-peptide interactions via chelation therapy holds considerable promise as a therapeutic strategy to combat this presently incurable disease. To this end, we developed two multifunctional carbohydrate-containing compounds N,N'-bis[(5-beta-D-glucopyranosyloxy-2-hydroxy)benzyl]-N,N'-dimethyl-ethane-1,2-diamine (H2GL1) and N,N'-bis[(5-beta-D-glucopyranosyloxy-3-tert-butyl-2-hydroxy)benzyl]-N,N'-dimethyl-ethane-1,2-diamine (H2GL2) for brain-directed metal chelation and redistribution. Acidity constants were determined by potentiometry aided by UV-vis and 1H NMR measurements to identify the protonation sites of H2GL1,2. Intramolecular H bonding between the amine nitrogen atoms and the H atoms of the hydroxyl groups was determined to have an important stabilizing effect in solution for the H2GL1 and H2GL2 species. Both H2GL1 and H2GL2 were found to have significant antioxidant capacity on the basis of an in vitro antioxidant assay. The neutral metal complexes CuGL1, NiGL1, CuGL2, and NiGL2 were synthesized and fully characterized. A square-planar arrangement of the tetradentate ligand around CuGL2 and NiGL2 was determined by X-ray crystallography with the sugar moieties remaining pendant. The coordination properties of H2GL1,2 were also investigated by potentiometry, and as expected, both ligands displayed a higher affinity for Cu2+ over Zn2+ with H2GL1 displaying better coordinating ability at physiological pH. Both H2GL1 and H2GL2 were found to reduce Zn2+- and Cu2+- induced Abeta1-40 aggregation in vitro, further demonstrating the potential of these multifunctional agents as AD therapeutics.
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Affiliation(s)
- Tim Storr
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada
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Boghaei DM, Gharagozlou M. Synthesis and characterization of novel water-soluble zinc(II) Schiff-base complexes derived from amino acids and salicylaldehyde-5-sulfonates. J COORD CHEM 2007. [DOI: 10.1080/00958970600858449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Davar M. Boghaei
- a Department of Chemistry , Sharif University of Technology , P. O. Box 11365-9516, Tehran, Iran
| | - Mehrnaz Gharagozlou
- a Department of Chemistry , Sharif University of Technology , P. O. Box 11365-9516, Tehran, Iran
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19
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Hill MS, Atwood DA. Synthesis and Reactivity of Five-Coordinate Indium Halides and Alkyls. MAIN GROUP CHEMISTRY 2006. [DOI: 10.1080/10241229812331341359] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Shakya R, Peng F, Liu J, Heeg MJ, Verani CN. Synthesis, Structure, and Anticancer Activity of Gallium(III) Complexes with Asymmetric Tridentate Ligands: Growth Inhibition and Apoptosis Induction of Cisplatin-Resistant Neuroblastoma Cells. Inorg Chem 2006; 45:6263-8. [PMID: 16878935 DOI: 10.1021/ic060106g] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Five gallium(III) complexes described as [Ga(III)(LX)2]ClO4, where (LX)- is the deprotonated form of a series of asymmetric ligands containing pyridine and 4,6-substituted phenol moieties, were synthesized and characterized by spectroscopic and spectrometric methods. Phenol substituents encompass the electron-withdrawing and electron-donating methoxy (1), nitro (2), chloro (3), bromo (4), and iodo (5) groups. Complexes 1 and 3 have had their molecular structure solved by X-ray crystallography and show distinct coordination modes. Complexes 1-5 were tested for growth-inhibition activity on cisplatin-resistant human neuroblastoma cells; those containing halogen substituents on the phenolate rings, i.e., 3-5, showed activity superior to that observed for cisplatin and induced apoptosis of neuroblastoma cells. Nitro-containing 2 suppressed proliferation of the neuroblastoma cells but induced apoptosis less effectively.
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Affiliation(s)
- Rajendra Shakya
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA
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Imbert C, Hratchian HP, Lanznaster M, Heeg MJ, Hryhorczuk LM, McGarvey BR, Schlegel HB, Verani CN. Influence of Ligand Rigidity and Ring Substitution on the Structural and Electronic Behavior of Trivalent Iron and Gallium Complexes with Asymmetric Tridentate Ligands. Inorg Chem 2005; 44:7414-22. [PMID: 16212367 DOI: 10.1021/ic050658j] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Species 1-6 are [M(III)(L)2]ClO4 complexes formed with the PhO--CH=N-CH2-Py imines, (L(I))- and (L(tBuI))-, and PhO--CH2-NH-CH2-Py amines, (L(A))- and (L(tBuA))-, in which PhO- is a phenolate ring and Py is a pyridine ring and the prefix tBu indicates the presence of tertiary butyl groups occupying the positions 4 and 6 of the phenol ring. Monometallic species with d5 high-spin iron (1, 2, 3, 4) and d10 gallium (5, 6) were synthesized and characterized to assess the influence of the ligand rigidity and the presence of tertiary butyl-substituted phenol rings on their steric, electronic, and redox behavior. Characterization by elemental analysis, mass spectrometry, IR, UV-visible, and EPR spectroscopies, and electrochemistry has been performed, and complexes [FeIII(L(tBuI))2]ClO4 (2), [FeIII(L(tBuA))2]ClO4 (4), and [Ga(III)(L(tBuI))2]ClO4 (5) have been characterized by X-ray crystallography. The crystal structures show the imine ligands meridionally coordinated to the metal centers, whereas the amine ligands are coordinate in a facial mode. Cyclic voltammetry shows that the complexes with the ligands (L(tBuI))- and (L(tBuA))- were able to generate ligand-based phenoxyl radicals, whereas unsubstituted ligands displayed ill-defined redox processes. EPR spectroscopy supports high-spin configurations for the iron complexes. UV-visible spectra are dominated by charge-transfer phenomena, and imine compounds exhibit dramatic hyperchromism when compared to equivalent amines. The tertiary butyl groups on the phenolate ring enhance this trend. Detailed B3LYP/6-31G(d)-level calculations have been used to account for the results observed.
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Affiliation(s)
- Camille Imbert
- Department of Chemistry, Wayne State University, 5101 Cass Ave. Detroit, Michigan 48202, USA
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Dutta B, Bag P, Nag K. Mononuclear Aliii, Gaiii and Iniii, and heterodinuclear GaiiiMii(M = Zn, Cu, Ni, Co) complexes of a tetraiminodiphenol macrocyclic ligand. NEW J CHEM 2005. [DOI: 10.1039/b507484c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hsieh WY, Liu S. Synthesis, Characterization, and Structures of Indium In(DTPA-BA2) and Yttrium Y(DTPA-BA2)(CH3OH) Complexes (BA = Benzylamine): Models for111In- and90Y-Labeled DTPA-Biomolecule Conjugates. Inorg Chem 2004; 43:6006-14. [PMID: 15360250 DOI: 10.1021/ic049973g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To explore structural differences in In3+, Y3+, and Lu3+ chelates, we prepared M(DTPA-BA2) complexes (M = In, Y, and Lu; DTPA-BA2 = N,N' '-bis(benzylcarbamoylmethyl)diethylenetriamine-N,N',N' '-triacetic acid) by reacting the trisodium salt of DTPA-BA2 with 1 equiv of metal chloride or nitrate. All three complexes have been characterized by elemental analysis, HPLC, IR, ES-MS, and NMR (1H and 13C) methods. ES-MS spectral and elemental analysis data are consistent with the proposed formula for M(DTPA-BA2) (M = In, Y, and Lu) and have been confirmed by the X-ray crystal structures of both In(DTPA-BA2) x 2H2O and Y(DTPA-BA2)(CH3OH) complexes. By a reversed-phase HPLC method, it was found that In(DTPA-BA2) is more hydrophilic than M(DTPA-BA2) (M = Y and Lu), most likely due to the dissociation of the two carbonyl oxygen donors in solution. The X-ray crystal structure of In(DTPA-BA2) revealed a rare example of an eight-coordinated In3+ complex with DTPA-BA2 bonding to the In3+ in a distorted square antiprism coordination geometry. Both benzylamine groups are in the trans position relative to the acetate-chelating arm that is attached to the central N atom. The Y3+ in Y(DTPA-BA2)(CH3OH) is nine-coordinated with an octadentate DTPA-BA2 and a methanol oxygen. The coordination geometry is best described as a tricapped trigonal prism. One benzylamine group is trans and the other cis to the acetate-chelating arm that is attached to the central N atom. All three M(DTPA-BA2) complexes (M = In, Y, and Lu) exist as at least three isomers in solution (approximately 10 mM), as shown by the presence of 6-8 overlapped 1H NMR signals from the methylene hydrogens of the benzylamine groups. The coordinated DTPA-BA2 remains rigid even at temperatures > 85 degrees C. The exchange rate between different isomers in M(DTPA-BA2) (M = In, Y, and Lu) is relatively slow at high concentrations (> 1.0 mM), but it is fast due to the partial dissociation and rapid interconversion of different isomers at lower concentrations ( approximately 10 mircroM). It is not surprising that M(DTPA-BA2) complexes (M = In, Y, and Lu) appear as a single peak in their respective HPLC chromatogram.
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Affiliation(s)
- Wen-Yuan Hsieh
- Department of Industrial and Physical Pharmacy, School of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, Indiana 47907, USA
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Liu S, He Z, Hsieh WY, Fanwick PE. Synthesis, characterization, and X-ray crystal structure of In(DOTA-AA) (AA = p-aminoanilide): a model for 111In-labeled DOTA-biomolecule conjugates. Inorg Chem 2004; 42:8831-7. [PMID: 14686864 DOI: 10.1021/ic0349914] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This report describes the synthesis and structural characterization of the indium complex of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid mono(p-aminoanilide) (DOTA-AA), a model compound for (111)In-labeled DOTA-biomolecule conjugates. In(DOTA-AA) was prepared by reacting DOTA-AA with 1 equiv of InCl(3) in 0.5 M ammonium acetate buffer (pH approximately 6). It was characterized by spectroscopic methods (IR, ES-MS, and (1)H NMR), elemental analysis, and X-ray crystallography. For comparison purposes, we also prepared the complex Y(DOTA-AA). ES-MS and (1)H NMR data are consistent with the proposed structure. HPLC analysis using a reversed phase method shows that the retention time of In(DOTA-AA) is approximately 2.0 min shorter than that of Y(DOTA-AA), demonstrating that In(DOTA-monoamide) is more hydrophilic than Y(DOTA-monoamide). In the solid state, In(DOTA-AA) has a twisted square antiprismatic coordination geometry with all eight donor atoms (N(4)O(4)) bonded to the In center. The average In-N and In-O distances are almost identical to those of Y-N and Y-O bonds found in Y(DOTA-d-Phe-NH(2)) even though the ionic radius of Y(3+) is much longer than that of In(3+). It seems that In(3+) does not fit the coordination cavity of DOTA-AA perfectly. The (1)H NMR data clearly demonstrated that In(DOTA-AA) becomes fluxional at room temperature, most likely due to dissociation of the acetamide-oxygen, rotation of acetate chelating arms, and inversion of ethylenic groups of the macrocyclic ring. Results from this study and our previous studies (Liu, S.; Pietryka, J.; Ellars C. E.; Edwards D. S. Bioconjugate Chem. 2002, 13, 902-913) suggest that the In(3+) complex of DOTA-monoamide in the solid state might be different from that in solution due to dissociation of the carbonyl-oxygen donor. Although Y(3+) and In(3+) complexes of DOTA-monoamide are both eight-coordinate in the solid state, the difference in their solution structures is most likely responsible for their difference in lipophilicity.
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Affiliation(s)
- Shuang Liu
- Department of Industrial and Physical Pharmacy, School of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, Indiana 47907, USA.
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Ocheskey JA, Polyakov VR, Harpstrite SE, Oksman A, Goldberg DE, Piwnica-Worms D, Sharma V. Synthesis, characterization, and molecular structure of a gallium(III) complex of an amine-phenol ligand with activity against chloroquine-sensitive Plasmodium falciparum strains. J Inorg Biochem 2003; 93:265-70. [PMID: 12576290 DOI: 10.1016/s0162-0134(02)00592-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Emergence of chloroquine-resistant Plasmodium falciparum strains necessitates discovery of novel antimalarial drugs, especially if the agents can be synthesized from commercially available, inexpensive precursors via short synthetic routes. While exploring structure-activity relationships, we found a gallium(III) complex, [(1,12-bis(2-hydroxy-5-methoxybenzyl)-1,5,8,12-tetraazadodecane)-gallium(III)](+) [Ga-5-Madd](+), 1, that possessed antimalarial efficacy. Like previously reported complexes, the crystal structure of 1 revealed gallium(III) in a symmetrical octahedral environment surrounded by four secondary amine nitrogen atoms in equatorial plane and two axial oxygen atoms. In contrast to a previously reported complex, [Ga-3-Madd](+), this novel metallo-antimalarial 1 possessed modest efficacy against chloroquine-sensitive HB3 Plasmodium lines. Thus, slight variation in the positions of methoxy functionalities on the aromatic rings of the organic scaffold dramatically altered specificity thereby suggesting a targeted (e.g., transporter- or receptor-mediated) rather than non-specific (e.g., pH or other gradient-mediated) mechanism of action for these agents.
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Affiliation(s)
- Joseph A Ocheskey
- Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO 63110, USA
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Edder C, Piguet C, Bernardinelli G, Mareda J, Bochet CG, Bünzli JC, Hopfgartner G. Unusual electronic effects of electron-withdrawing sulfonamide groups in optically and magnetically active self-assembled noncovalent heterodimetallic d-f podates. Inorg Chem 2000; 39:5059-73. [PMID: 11233203 DOI: 10.1021/ic000687o] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The segmental ligand 2-(6-(N,N-diethylcarbamoyl)pyridin-2-yl)-1,1'-dimethyl-2'-(5-(N,N-diethylsulfonamido)-pyridin-2-yl)-5,5'-methylenebis[1H-benzimidazole] (L3) is synthesized via a multistep strategy that allows the selective introduction of an electron-withdrawing sulfonamide group into the ligand backbone and its subsequent hydrolysis to the hydrophilic sulfonate group. Compared to that of the methylated analogue L1, the affinity of the bidentate binding unit of L3 for H+ and for trivalent lanthanide ions (LnIII) in [Ln(L3)3]3+ and [Ln2(L3)3]6+ is reduced because the electron-withdrawing sulfonamide substituent weakens sigma-bonding, but improved retro-pi-bonding between the bidentate binding units of L3 and soft 3d-block ions (M(II) = FeII, ZnII) overcomes this effect and leads to homometallic complexes [Mn(L(i))m]2n+ (i = 1, 3) displaying similar stabilities. Theoretical ab initio calculations associate this dual effect with a global decrease in energy of pi and sigma orbitals when the sulfonamide group replaces the methyl group, with an extra stabilization for the LUMO (pi). The reaction of L3 with a mixture of LnIII and M(II) (M = Fe, Ni, Zn) in acetonitrile gives the noncovalent podates [LnM(L3)3]5+ in which LnIII is nine-coordinated by the three wrapped tridentate segments, while the bidentate binding units provide a facial pseudooctahedral site around M(II). The X-ray structure of [EuZn(L3)3](ClO4)4(PF6)(CH3NO2)3(H2O) reveals that the bulky sulfonamide group at the 5-position of the pyridine ring only slightly increases the Zn-N bond distances as a result of sigma/pi compensation effects. The introduction of spectroscopically and magnetically active FeII and NiII into the pseudooctahedral site allows the detailed investigation of the electronic structure of the bidentate segment. Absorption spectra, combined with electrochemical data, experimentally demonstrate the dual effect associated with the attachment of the sulfonamide group (decrease of the sigma-donating ability of the pyridine lone pair and increase of the pi-accepting properties of the coordinated bidentate binding unit). The influences on the ligand field strength and on tunable room-temperature FeII spin-crossover processes occurring in [LnFe(L3)3]5+ are discussed, together with the origin of the entropic control of the critical temperature in these thermal switches.
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Affiliation(s)
- C Edder
- Department of Inorganic, Analytical, and Applied Chemistry, University of Geneva, Switzerland
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Sharma V, Beatty A, Wey SP, Dahlheimer J, Pica CM, Crankshaw CL, Bass L, Green MA, Welch MJ, Piwnica-Worms D. Novel gallium(III) complexes transported by MDR1 P-glycoprotein: potential PET imaging agents for probing P-glycoprotein-mediated transport activity in vivo. CHEMISTRY & BIOLOGY 2000; 7:335-43. [PMID: 10801474 DOI: 10.1016/s1074-5521(00)00111-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Multidrug resistance (MDR) mediated by expression of MDR1 P-glycoprotein (Pgp) represents one of the best characterized barriers to chemotherapy in cancer patients. Positron emission tomography (PET) agents for analysis of Pgp-mediated drug transport activity in vivo would enable noninvasive assessment of chemotherapeutic regimens and MDR gene therapy. RESULTS Candidate Schiff-base phenolic gallium(III) complexes were synthesized from their heptadentate precursors and gallium(III)acetylacetonate. Crystal structures demonstrated a hexacoordinated central gallium with overall trans-pseudo-octahedral geometry. Radiolabeled (67)Ga-complexes were obtained in high purity and screened in drug-sensitive (Pgp(-)) and MDR (Pgp(+)) tumor cells. Compared with control, lead compound 6. demonstrated antagonist-reversible 55-fold lower accumulation in Pgp-expressing MDR cells. Futhermore, compared with wild-type control, quantitative pharmacokinetic analysis showed markedly increased penetration and retention of 6. in brain and liver tissues of mdr1a/b((-/-)) gene disrupted mice, correctly mapping Pgp-mediated transport activity at the capillary blood-brain barrier and hepatocellular biliary cannalicular surface in vivo. CONCLUSIONS These results indicate that gallium(III) complex 6. is recognized by MDR1 Pgp as an avid transport substrate, thereby providing a useful scaffold to generate (68)Ga radiopharmaceuticals for molecular imaging of Pgp transport activity in tumors and tissues in vivo using PET.
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Affiliation(s)
- V Sharma
- Department of Molecular Biology and Pharmacology, Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO 63110, USA
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Xu Z, Read PW, Hibbs DE, Hursthouse MB, Abdul Malik KM, Patrick BO, Rettig SJ, Seid M, Summers DA, Pink M, Thompson RC, Orvig C. Coaggregation of paramagnetic d- and f-block metal ions with a podand-framework amine phenol ligand. Inorg Chem 2000; 39:508-16. [PMID: 11229570 DOI: 10.1021/ic991171b] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This report covers initial studies in the coaggregation of nickel (Ni2+) and lanthanide (Ln3+) metal ions to form complexes with interesting structural and magnetic properties. The tripodal amine phenol ligand H3tam (1,1,1-tris(((2-hydroxybenzyl)amino)methyl)ethane) is shown to be particularly accommodating with respect to the geometric constraints of both transition and lanthanide metal ions, forming isolable complexes with both of these ion types. In the solid-state structure of [Ni(H2tam)(CH3CN)]PF6.2.5CH3CN.0.5CH3OH (1), the Ni(II) center has a distorted octahedral geometry, with an N3O2 donor set from the [H2tam]- ligand and a coordinated solvent (acetonitrile) occupying the sixth site. The reaction of stoichiometric amounts of H3tam with the Ni(II) ion in the presence of lanthanide(III) ions provides [LnNi2(tam)2]+ cationic complexes which contain coaggregated metal ions. These complexes are isolable and have been characterized by a variety of analytical techniques, with mass spectrometry proving to be particularly diagnostic. The solid-state structures of [LaNi2(tam)2(CH3OH)1/2(CH3CH2OH)1/2(H2O)]ClO4.0.5CH3OH.0.5CH3CH2OH.4H2O (2), [DyNi2(tam)2(CH3OH)(H2O)]ClO4.CH3OH. H2O(6), and [YbNi2(tam)2(H2O)]ClO4.2.58H2O(9) have been determined. Each complex contains two octahedral Ni(II) ions, each of which is encapsulated by the ligand tam3- in an N3O3 coordination sphere; each [Ni(tam)]-unit caps the lanthanide(III) ion via bridging phenoxy oxygen donor atoms. In 2, La3+ is eight-coordinated, while in 6, Dy(III) is seven- (to "weakly eight-") coordinated, and Yb(III) in 9 has a six-coordination environment. The complexes are symmetrically different, 2 possessing C2 symmetry and 6 and 9 having C1 symmetry. Magnetic studies of 2, 6, and 9 indicate that antiferromagnetic exchange coupling between the Ni(II) and Ln(III) ions increases with decreasing ionic radius of Ln(III).
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Affiliation(s)
- Z Xu
- Department of Chemistry, University of British Columbia, Vancouver, Canada
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Bhattacharyya P, Parr J, Slawin AM. Novel bimetallic lead(II) complexes of polydentate amine-phenol ligands. INORG CHEM COMMUN 1999. [DOI: 10.1016/s1387-7003(99)00025-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Polyakov VR, Sharma V, Crankshaw CL, Piwnica-Worms D. Synthesis, Molecular Structure, and Properties of a Neutral Schiff Base Phenolic Complex of Magnesium. Inorg Chem 1998; 37:4740-4742. [PMID: 11670631 DOI: 10.1021/ic971466u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Valery R. Polyakov
- Laboratory of Molecular Radiopharmacology, Departments of Radiology and Molecular Biology and Pharmacology, Washington University Medical School, St. Louis, Missouri 63110
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Achour B, Costa J, Delgado R, Garrigues E, Geraldes CFGC, Korber N, Nepveu F, Prata MI. Triethylenetetramine-N,N,N',N",N"',N"'-hexaacetic Acid (TTHA) and TTHA-Bis(butanamide) as Chelating Agents Relevant to Radiopharmaceutical Applications. Inorg Chem 1998; 37:2729-2740. [PMID: 11670409 DOI: 10.1021/ic970921j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The N,N'-bis(butanamide) derivative of TTHA (TTHA = triethylenetetramine-N,N,N',N",N"',N"'-hexaacetic acid), and its Ga(3+) and In(3+) complexes were synthesized and characterized. The crystal X-ray diffraction structure of [Ga(2)(OH)(2)(TTHA)][Na(2)(H(2)O)(6)].2H(2)O was determined. The complex crystallizes in the monoclinic space group P2(1)/n with a = 7.179(2) Å, b = 20.334(3) Å, c = 10.902(5) Å, beta = 101.90(2) degrees, and Z = 2. Each gallium atom is bonded to six donor atoms (N(2)O(4)) in a slightly distorted octahedral geometry. The values of the protonation constants and the protonation sequence were determined by potentiometry and NMR. The stability constants of the Al(3+), Ga(3+), Fe(3+), and In(3+) complexes of TTHA-(BuA)(2) and of the Ga(3+) complex of TTHA were determined by potentiometry. The structures, in solution, of the Al(3+), Ga(3+), and In(3+) complexes of TTHA-(BuA)(2) and TTHA were analyzed by (1)H, (13)C, (27)Al, (71)Ga, and (115)In NMR techniques. Derivatization of two terminal carboxylates by butanamide substituents leads to a significant decrease of the total ligand basicity (5.77 log units) and to a change of the solubility of the resulting complexes. The stability constant of the ML complexes of TTHA-(BuA)(2) with Fe(3+) exhibits the highest value of the series (10(23.92)). The In(3+) complex is more stable than that of Ga(3+) and almost as stable as that of the Fe(3+). However, the decrease in indium and iron complex stability is less drastic going from TTHA to TTHA-(BuA)(2) (about 3 log units) than for Al(3+) or Ga(3+) (about 6 log units). pM values calculated under physiological conditions for DTPA, TTHA, and the bis(butanamide) derivatives have shown that while DTPA remains a ligand of choice to chelate Fe(3+) and In(3+) ions in vivo compared to transferrin as competitor ligand, TTHA, surprisingly, appears to be the best of these four ligands (pM = 22.71) to chelate Ga(3+).
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Affiliation(s)
- Benbrahim Achour
- Laboratoire de Synthèse, Physico-Chimie et Radiobiologie, Université Paul Sabatier, 31062 Toulouse Cedex 4, France, Instituto de Tecnologia Química e Biológica, R. da Quinta Grande, 6, 2780 Oeiras, Portugal, Faculdade de Farmácia de Lisboa, Av. das Forças Armadas, 1600 Lisboa, Portugal, Instituto Superior Técnico, DEQ, 1096 Lisboa Codex, Portugal, Departmento de Bioquímica e Centro de Neurociências, Universidade de Coimbra, Apartado 3126, 3000 Coimbra, Portugal, and Universität Bonn, Anorganische Chemie, Gerhard Domagk-Strasse 1, D-6000 Bonn, Germany
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Extraction behavior of divalent first row transition metal ions with N,N′-bis(2-hydroxyphenylmethyl)-N,N′-bis(2-pyridylmethyl)-1,2-ethanediamine and its derivatives. Talanta 1997; 44:2019-25. [DOI: 10.1016/s0039-9140(96)02200-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/1996] [Revised: 12/03/1996] [Indexed: 11/22/2022]
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Caravan P, Rettig SJ, Orvig C. Effect of Pyridyl Donors in the Chelation of Aluminum(III), Gallium(III), and Indium(III). Inorg Chem 1997; 36:1306-1315. [PMID: 11669706 DOI: 10.1021/ic961230a] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new preparation of N,N'-bis(2-pyridylmethyl)ethylenediamine-N,N'-diacetic acid (H(2)bped) is reported, and its properties of complexation with Al(III), Ga(III), In(III), and Co(III) are investigated. The molecular structure of the cobalt(III) complex [Co(bped)]PF(6).CH(3)CN.H(2)O (C(20)H(25)CoF(6)N(5)O(5)P) has been solved by X-ray methods; the complex crystallizes in the triclinic space group P&onemacr;, with a = 10.611(2) Å, b = 12.720(2) Å, c = 9.868(1) Å, alpha = 102.70(1) degrees, beta =93.60(1) degrees, gamma = 106.96(1) degrees, and Z = 2. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.041 (R(w) = 0.038) for 4312 reflections with I > 3sigma(I). The Co(III) ion is coordinated in a distorted octahedral geometry with an N(4)O(2) donor atom set. The carboxylato oxygen atoms are coordinated trans, while the pyridyl nitrogen atoms are coordinated cis. The largest distortion from octahedral geometry is the N(pyridyl)-Co-N(pyridyl) angle of 107 degrees. Complex formation constants have been measured at 25 degrees C (&mgr; = 0.16 M (NaCl)). log K([M(bped)](+)) (log K([M(bped)(OH)])): M = Al, 10.85 (6.37); M = Ga, 19.89 (15.62); M = In, 22.6 (15.44). A protonated complex was also detected, [Ga(Hbped)](2+), log K = 21.79. The order of stability is In(III) > Ga(III) > Al(III) for the binary species, [M(bped)](+). The solution structures of the complexes have been probed in multinuclear NMR ((1)H, (13)C, (27)Al) studies, and these solution structures are compared with the solid state structure of the cobalt(III) complex. The complexes [In(bped)](+) and [In(bped)(OH)] are proposed to contain 7-coordinate In(III) with water and hydroxide completing the respective coordination spheres. The gallium complexes are proposed to be 6-coordinate: the [Ga(Hbped)](2+) complex contains a nondeprotonated carboxylic acid group which is not coordinated, and [Ga(bped)(OH)] contains a coordinated hydroxide which displaces a carboxylato donor. The [Al(bped)(OH)] complex may be 5-coordinate on the basis of its downfield (27)Al NMR chemical shift, 54 ppm.
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Affiliation(s)
- P. Caravan
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1
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Caravan P, Orvig C. Tripodal Aminophenolate Ligand Complexes of Aluminum(III), Gallium(III), and Indium(III) in Water. Inorg Chem 1997. [DOI: 10.1021/ic961222u] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- P. Caravan
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Chris Orvig
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
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Atwood D, Jegier J. Halide Effects in the Formation of Four-Coordinate, Cationic Aluminum. Inorg Chem 1996; 35:4277-4282. [PMID: 11666642 DOI: 10.1021/ic960344j] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work was conducted as part of a broad-based effort to determine the factors that affect cation formation for organometallic aluminum complexes. In this study the adduct species R(2)AlX.NH(2)(t)Bu (R, X: Me, F (1); Me, Cl (2); Et, Cl (3); Me, Br (4)) and cationic complexes [R(2)Al(NH(2)(t)Bu)(2)]X (R, X: Me, Br (5); Et, Br (6); Me, I (7)) were examined. These complexes demonstrate that the reaction of R(2)AlX with excess NH(2)(t)Bu produces cationic complexes only when X = Br or I. All of the compounds were characterized by melting points, (1)H NMR, IR, elemental analyses, and, in some cases, X-ray crystallography. X-ray data: 2, triclinic, P&onemacr;, a = 6.277(3) Å, b = 8.990(3) Å, c = 10.393(3) Å, alpha = 71.97(1) degrees, beta = 80.25(3) degrees, gamma = 81.97(3) degrees, V = 547.0(4) Å(3), Z = 2, 1032 reflections with F > 4.0 sigma(F), R = 0.0520; 5, monoclinic, P2(1)/c, a = 9.099(1) Å, b = 10.292(1) Å, c = 17.255(2) Å, beta = 104.81(1) degrees, V = 1562.1(3) Å(3), Z = 4, 1464 reflections with F > 4.0 sigmaF, R = 0.0387; 6, monoclinic, P2(1)/c, a = 14.122(2) Å, b = 13.539(2) Å, c = 21.089(2) Å, beta = 107.73(1) degrees, V = 3841.2(9) Å(3), Z = 4, 781 reflections with F > 5.0 sigmaF, R = 0.0873; 7, monoclinic, P2(1)/n, a = 9.071(1) Å, b = 10.529(1) Å, c = 17.714(2) Å, beta = 103.67(1) degrees, V = 1644.0(3) Å(3), Z = 4, 1723 reflections with F > 4.0 sigmaF, R = 0.0451.
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Affiliation(s)
- David Atwood
- Center for Main Group Chemistry, Department of Chemistry, North Dakota State University, Fargo, North Dakota 58105
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Lowe MP, Rettig SJ, Orvig C. Highly Symmetric Group 13 Metal−Phosphinato Complexes: Multinuclear NMR (27Al,31P,71Ga) Determination of Stability Constants at Low pH. J Am Chem Soc 1996. [DOI: 10.1021/ja961633+] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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