Konstantinos Skobridis

University of Ioannina, Yannina, Epirus, Greece

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Publications (42)93.84 Total impact

  • Hendrik Klien · Wilhelm Seichter · Konstantinos Skobridis · Edwin Weber
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    ABSTRACT: Having reference to an elongated structural modification of 2,2′-bis(hydroxydiphenylmethyl)biphenyl, (I), the two 1,1′:4′,1′′-terphenyl-based diol hosts 2,2′′-bis(hydroxydiphenylmethyl)-1,1′:4′,1′′-terphenyl, C44H34O2, (II), and 2,2′′-bis[hydroxybis(4-methylphenyl)methyl]-1,1′:4′,1′′-terphenyl, C48H42O2, (III), have been synthesized and studied with regard to their crystal structures involving different inclusions, i.e. (II) with dimethylformamide (DMF), C44H34O2·C2H6NO, denoted (IIa), (III) with DMF, C48H42O2·C2H6NO, denoted (IIIa), and (III) with acetonitrile, C48H42O2·CH3CN, denoted (IIIb). In the solvent-free crystals of (II) and (III), the hydroxy H atoms are involved in intramolecular O—H...π hydrogen bonding, with the central arene ring of the terphenyl unit acting as an acceptor. The corresponding crystal structures are stabilized by intermolecular C—H...π contacts. Due to the distinctive acceptor character of the included DMF solvent species in the crystal structures of (IIa) and (IIIa), the guest molecule is coordinated to the host via O—H...O=C hydrogen bonding. In both crystal structures, infinite strands composed of alternating host and guest molecules represent the basic supramolecular aggregates. Within a given strand, the O atom of the solvent molecule acts as a bifurcated acceptor. Similar to the solvent-free cases, the hydroxy H atoms in inclusion structure (IIIb) are involved in intramolecular hydrogen bonding, and there is thus a lack of host–guest interaction. As a result, the solvent molecules are accommodated as C—H...N hydrogen-bonded inversion-symmetric dimers in the channel-like voids of the host lattice.
    Acta crystallographica. Section C 09/2015; 71(Pt 9). DOI:10.1107/S2053229615014035
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    ABSTRACT: New calixarene-based dendrimers, containing calix[4]arene as the core and different generations of Fréchet-type poly(benzyl ether) dendrons as building blocks, which possess either Br-atoms or COOtBu groups at their surface were synthesized and presented herein for the first time. The new calix[4]arene-cored dendritic macromolecules were fully characterized and found to prefer strictly the cone conformation.
    Helvetica Chimica Acta 05/2015; 98(5):593-603. DOI:10.1002/hlca.201400304 · 1.14 Impact Factor
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    ABSTRACT: Factor-inhibiting hypoxia-inducible factor (HIF)-1 (FIH-1) is an asparaginyl β-hydroxylase enzyme that was initially found to hydroxylate the HIF-α, preventing its transcriptional activity and leading to adaptive responses to hypoxia. More recently, other substrates, such as neurogenic locus notch homolog (Notch), have been found to be alternative FIH targets, but the biologic relevance of this regulation was never investigated. Given the key function of Notch in angiogenesis, we here investigate the role of FIH/Notch signaling in endothelial cells. We report that FIH-1 silencing in HUVECs results in reduced growth and increased apoptosis. The knockdown of FIH is associated with increased Notch2 activity, leading to enhanced expression of the Notch target hairy/enhancer-of-split related with YRPW motif protein 1 (Hey-1). Consistent with recent findings showing that Notch2 suppresses survivin (a key inhibitor of apoptosis), FIH targeting in HUVEC leads to selective repression of survivin in endothelial cells, thus promoting cell apoptosis and growth arrest. Our data support the concept that FIH-1 may interact with Notch2 and repress its activity, thereby playing a critical role in controlling the survival of vascular endothelial cells. These findings might pave the way toward novel, antiangiogenic strategies in disorders that are characterized by excessive vascular growth, such as cancer and rheumatoid arthritis.-Kiriakidis, S., Henze, A.-T., Kruszynska-Ziaja, I., Skobridis, K., Theodorou, V., Paleolog, E. M., Mazzone, M. Factor-inhibiting HIF-1 (FIH-1) is required for human vascular endothelial cell survival. © FASEB.
    The FASEB Journal 04/2015; 29(7). DOI:10.1096/fj.14-252379 · 5.04 Impact Factor
  • ChemInform 01/2015; 46(2). DOI:10.1002/chin.201502250
  • Ingo Knepper · Wilhelm Seichter · Prof. Dr. Konstantinos Skobridis · Edwin Weber · Vassiliki Theodorou
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    ABSTRACT: Four trityl compounds differing both in the functional group (OH, OMe, NH2) at the specific trityl carbon and a para substituent, being bromine or phenyl at one of the phenyl groups, have been prepared and structurally studied by means of single crystal X-ray diffraction and making use of Hirshfeld surface analysis. Compared to the structures of corresponding prototypes and analogues, specific interaction modes and packing motifs including cluster aggregates as well as non-cluster type structures depending on the substitution and involving polymorphism were found, opening potential trend prediction with reference to crystal engineering being useful in this compound class.
    CrystEngComm 01/2015; DOI:10.1039/C5CE00871A · 4.03 Impact Factor
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    ABSTRACT: Imatinib mesylate is the leading compound to treat chronic myeloid leukemia (CML) and other cancers, through its inhibition of Bcr-Abl tyrosine kinases. However, resistance to imatinib develops frequently, particularly in late-stage disease and has necessitated the development of new Bcr-Abl inhibitors. The synthesis of a new series of phenylaminopyrimidines, structurally related to imatinib, showed large interest since the introduction of nilotinib. Here, we compare the protein levels in K562 cells treated with either imatinib or with novel imatinib derivates. Our results revealed that among the 986 quantified proteins, 35 had significantly altered levels of expression by imatinib or its derivates. In a second series of experiments, we directly compared the proteomes of imatinib treated K562 cells with those K562 cells treated with any of the four imatinib derivates. More than 1029 protein were quantified, 80 of which had altered levels of expression. Both experiments pointed to changes in the expression of the ATP-dependent RNA helicase DDX3X and of two mitochondrial coiled-coil-helix-coiled-coil-helix domain-containing proteins.
    07/2014; 2:363-381. DOI:10.3390/proteomes2030363
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    ABSTRACT: This review is a critical survey of the literature that aims to highlight the most significant developments on synthetic strategies involving stable oxygen isotopes ([(17) O] and [(18) O]). The labeling methodologies are categorized in groups, according to the oxygen-containing functional group. Copyright © 2014 John Wiley & Sons, Ltd.
    Journal of Labelled Compounds and Radiopharmaceuticals 06/2014; 57(8). DOI:10.1002/jlcr.3212 · 1.27 Impact Factor
  • Vassiliki Theodorou · Marina Gogou · Aimilia Giannoussi · Konstantinos Skobridis
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    ABSTRACT: During the N-benzoylation reaction for the synthesis of N-substituted aminopyrimidines, an undesired N,N-diacylation reaction took place. The extension of this N-acylation reaction to a series of several 2-aminopyrimidines, aminopyrazines and highly deactivated anilines produced analogous results. The possible mechanism responsible for that behavior is investigated and an advantageous alternative procedure for the clean formation of the desired amides is suggested.
    Archive for organic chemistry 01/2014; · 1.17 Impact Factor
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    ABSTRACT: The asymmetric unit of the title compound, C44H30O2, contains two independent mol-ecules in which the terminal rings of the terphenyl element are inclined at angles of 36.3 (1) and 22.5 (1)° with respect to the central ring and the dihedral angles between the fluorenyl units are 72.3 (1) and 62.8 (1)°. In the crystal, pairs of O-H⋯O hydrogen bonds link the mol-ecules into inversion dimers. The hy-droxy H atoms not involved in these hydrogen bonds form O-H⋯π inter-actions in which the central terphenyl rings act as acceptors. Weak C-H⋯O contacts and π-π [centroid-centroid distance = 4.088 (2) Å] stacking inter-actions also occur. Taking into account directed non-covalent bonding between the molecules, the crystal is constructed of supramolecular strands extending along the a-axis direction.
    Acta Crystallographica Section E Structure Reports Online 10/2013; 69(Pt 10):o1514-o1515. DOI:10.1107/S1600536813024033 · 0.35 Impact Factor
  • Konstantinos Skobridis · Vassiliki Theodorou · Wilhelm Seichter · Edwin Weber
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    ABSTRACT: The diol host compound 2 featuring a structure with two 9-fluorenol moieties attached in 3,3′-position to a biphenyl core unit has been synthesized and is shown to form crystalline inclusion complexes with organic guest molecules. Aside from the single-crystal X-ray structures of unsolvated 2 in two polymorphous forms (2A, 2B), structures of five inclusion compounds with 1,4-dioxane (2a), DMSO (2b), diethylamine (2c), acetic acid (2d), and ethyl acetate (2e) are described and comparatively discussed in the interaction behavior including corresponding host compounds with different attachment mode of the biphenyl unit and the diphenylhydroxymethyl-substituted equivalent.
    Crystal Growth & Design 08/2013; 13(9):3985–3995. DOI:10.1021/cg400707s · 4.89 Impact Factor
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    ABSTRACT: The formation of crystalline host–guest complexes of three constitutionally isomeric host compounds 1–3 featuring two diphenylhydroxymethyl groups attached in different positions to a biphenylylene central moiety is studied. Dependent on the connection mode (2,2′-, 3,3′-, or 4,4′-) with reference to the biphenylylene unit, a distinctly different complex behavior of the host compounds is observed. X-ray crystal structures of the solvent-free hosts are reported including a third polymorph with respect to already known polymorphous structures. The crystal structures of eight host–guest complexes of 1–3, including a pair of complexes differing only in the host/guest stoichiometry, are described and comparatively discussed covering the structures of known complex species of the isomeric hosts. Correlations between the constitutional isomerism of the host molecules and their conformational as well as packing structures in the crystalline state, both in unsolvated and solvent complexed form, are demonstrated providing potential usefulness in the future design of crystalline host–guest complexes.
    Crystal Growth & Design 10/2011; 11(12):5275–5288. DOI:10.1021/cg200750q · 4.89 Impact Factor
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    ABSTRACT: α,β-Unsaturated acids, through their acid chlorides, react with tritylamine in the presence of triethylamine under mild conditions, to afford in high yield and high regioselectivity the corresponding β,γ-unsaturated tritylamides. Detritylation with TFA generates quantitatively β,γ-unsaturated primary amides. An investigation of this deconjugative isomerization was performed.
    Tetrahedron 08/2011; 67(31):5630-5634. DOI:10.1016/j.tet.2011.05.096 · 2.64 Impact Factor
  • Konstantinos Skobridis · Vassiliki Theodorou · Wilhelm Seichter · Edwin Weber
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    ABSTRACT: The X-ray crystallographic structures of four new inclusion compounds of the versatile clathrate host 2,2′-bis(9-hydroxy-9-fluorenyl)biphenyl (1) as well as the crystal structure of the unsolvated host are reported and comparatively discussed with regard to the molecular conformation and the modes of interactions the molecules make use of in the crystal packing. While the inclusion crystals demonstrate full saturation of the hydrogen bond capacity of the host molecule, 1 is only involved in weak intermolecular π-contacts in the solvent-free structure. We draw the conclusion that the well-tried strategy of coordinato-clathration, underlying the present inclusion compounds, should not be regarded as a strict rule with reference to the formation of inclusion crystals but a helpful framework in the search of new efficient clathrate hosts.
    Crystal Growth & Design 12/2009; 10(2). DOI:10.1021/cg901217k · 4.89 Impact Factor
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    ABSTRACT: The ability of a series of crown ether-functionalized dendrimers to function as alkali metal picrate extraction agents is assessed by liquid-liquid extraction and (1)H NMR titration experiments. Crown ether-functionalized dendrimers that contain Frechet-type poly(benzyl ether) dendrons of different generation as building blocks display different extraction characteristics toward alkali metal cations. Positive and negative dendritic effects depending on the generation of the dendrimer are assigned in the complexation behaviour of the dendritic host compounds.
    Tetrahedron Letters 11/2009; 50(44):6019 - 6021. DOI:10.1016/j.tetlet.2009.08.053 · 2.38 Impact Factor
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    ABSTRACT: Imatinib is a clinically important ATP analogue inhibitor that targets the tyrosine kinase domain of the intracellular Abl kinase and the PDGF receptor family. Imatinib has revolutionised the treatment of chronic myeloid leukaemia, which is caused by the oncogene Bcr-Abl and certain solid tumours that harbor oncogenic mutations of the PDGF receptor family. As a leading kinase inhibitor, imatinib also provides an excellent model system to investigate how changes in drug design impact biological activity, which is an important consideration for rational drug design. Herein we report a new series of imatinib derivatives that in general have greater activity against the family of PDGF receptors and poorer activity against Abl, as a result of modifications of the phenyl and N-methylpiperazine rings. These new compounds provide a platform for further drug development against the therapeutically important PDGF receptor family and they also provide insight into the engineering of drugs with altered biological activity.
    ChemMedChem 11/2009; 5(1):130-9. DOI:10.1002/cmdc.200900394 · 2.97 Impact Factor
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    ABSTRACT: A new synthetic route to primary amides via N-tritylamides was developed. The initially formed N-tritylamides, derived from acylation of tritylamine by activated carboxylic acid derivatives, were deprotected with trifluoroacetic acid at room temperature to the desired primary amides in good yields.
    01/2009; 2009(11).
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 02/2008; 39(8). DOI:10.1002/chin.200808052
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    ABSTRACT: A very mild and rapid procedure for the efficient alkaline hydrolysis of esters in non-aqueous conditions has been developed, by the use of dichloromethane/methanol (9:1) as solvent. This method conveniently provides both carboxylic acids and alcohols from the corresponding esters and sodium hydroxide in a few minutes at room temperature. A plausible reaction mechanism is proposed.
    Tetrahedron Letters 11/2007; 48(46):8230-8233. DOI:10.1016/j.tetlet.2007.09.074 · 2.38 Impact Factor
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    ABSTRACT: Four crystalline inclusion compounds of the 2,20-bis( 9hydroxy- 9- fluorenyl) biphenyl host 1, containing diethylene glycol ( 1: 1) ( 1a), bis( 2- aminoethyl) amine ( 1: 1) ( 1b), methacrylic acid ( 1: 1) ( 1c) and 2- cyclopenten- 1- one ( 1: 2) ( 1d), have been studied by X- ray diffraction analysis from single crystals. Departure from the expectation, the multifunctional and conjugate functional guest molecules, potentially being able to offer multiple H donor-/ acceptorships or other modes of polar interaction due to the conjugation, do not result in the formation of infinitely connected networks in the crystal structures. Instead of this, discrete 2: 2 host - guest aggregates ( 1a, 1b), guest dimers ( 1c) and rather conventional host - guest units ( 1d) are found. Hence, inherent shielding effects of the host molecule owing to the fluorenyl moieties and the presence of a strong intramolecular hydrogen bond, impeding multiple intermolecular association, are not overcome by the merits of the guest molecules, showing that the host compound 1 is superior by structural constancy in its crystalline inclusions.
    Supramolecular Chemistry 09/2007; 19(6):373-382. DOI:10.1080/10610270600987895 · 2.39 Impact Factor
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    ABSTRACT: Novel lipophilic dendrimers as host compounds, that is, 7-15, containing crown ether moieties with different sizes as the core, surrounded by first, second or third generation poly(aromatic ether) wedges, were synthesized by the use of bis(bromomethyl)-substituted crown ethers and Frechet-type poly(benzyl ether) dendrons as building blocks. The compounds were fully characterized. (c) 2007 Elsevier Ltd. All rights reserved.
    Tetrahedron Letters 06/2007; 48(23):4091 - 4095. DOI:10.1016/j.tetlet.2007.04.014 · 2.38 Impact Factor

Publication Stats

406 Citations
93.84 Total Impact Points


  • 2003–2015
    • University of Ioannina
      • Department of Chemistry
      Yannina, Epirus, Greece
  • 1994–1997
    • Technische Universität Bergakademie Freiberg
      • Institute of Organic Chemistry
      Freiburg, Saxony, Germany
  • 1993
    • University of Madras
      Chennai, Tamil Nadu, India
    • University of Bonn
      • Kekulé Institute of Organic Chemistry and Biochemistry
      Bonn, North Rhine-Westphalia, Germany
  • 1992
    • University of Cape Town
      Kaapstad, Western Cape, South Africa