106967-42-4Relevant academic research and scientific papers
Preparation of n-boc-(2,6-bis-(ethoxycarbonyl)pyridin 4-yl)-L-alanines as tridentate ligands
Schmidt, Boris,Ehlert, Dennis K.
, p. 3999 - 4002 (1998)
The pyridylalanine 7a was synthesised in good yield from serine and 4- bromopyridine 3. The pyridylpropionates 12, 13 were synthesised in good yields by either Heckolefination or palladium catalysed cross coupling.
The Influence of para Substituents in Bis(N-Heterocyclic Carbene) Palladium Pincer Complexes for Electrocatalytic CO2 Reduction
Therrien, Jeffrey A.,Wolf, Michael O.
, p. 1161 - 1172 (2017)
The effect of modifying the pyridyl para position of lutidine-linked bis(N-heterocyclic carbene) Pd pincer complexes is studied both experimentally (R = OMe, H, Br, and COOR) and computationally, showing a strong effect on the first reduction potential of the complex and allowing the reduction potential to be tuned over a wide range in relation to the Hammett σp constant of the para substituent. The effect of the pyridyl para substituent on electron density of the metal center, frontier orbital energies, and dissociation energy of the trans ligand are also investigated in the context of reactivity with CO2 through electrochemical characterization of the complexes under N2 and CO2 and controlled potential electrolysis experiments where CO2 is reduced to CO.
Design, synthesis and structural investigation of a 1-D directional coordination network based on the self-assembly of an unsymmetrical mono-tridentate ligand and cobalt cation
Jouaiti,Hosseini,De Cian
, p. 1863 - 1864 (2000)
Using an exo ligand containing a pyridine unit as a monodentate coordination site and a PyS2 moiety as a tridentate coordination pole, a directional 1-D coordination network has been obtained in the presence of CoCl2 under self-assembly conditions; a single-crystal X-ray study revealed that in the crystalline phase the 1-D networks are packed in a centrosymmetric fashion.
Photocytotoxicity of Oligothienyl-Functionalized Chelates That Sensitize LnIII Luminescence and Generate 1O2
Johnson, Katherine R.,Lombardi, Vincent C.,de Bettencourt-Dias, Ana
, p. 12060 - 12066 (2020)
Three new compounds containing a heptadentate lanthanide (LnIII) ion chelator functionalized with oligothiophenes, nThept(COOH)4 (n=1, 2, or 3), were isolated. Their LnIII complexes not only display the characteristic metal-centered emission in the visible or near-infrared (NIR) but also generate singlet oxygen (1O2). Luminescence efficiencies (?Ln) for [Eu1Thept(COO)4]? and [Eu2Thept(COO)4]? are ?Eu=3 percent and 0.5 percent in TRIS buffer and 33 percent and 3 percent in 95 percent ethanol, respectively. 3Thept(COO)44? does not sensitize EuIII emission due to its low-lying triplet state. Near infra-red (NIR) luminescence is observed for all NIR-emitting LnIII and ligands with efficiencies of ?Yb=0.002 percent, 0.005 percent and 0.04 percent for [YbnThept(COO)4]? (n=1, 2, or 3), and ?Nd=0.0007 percent, 0.002 percent and 0.02 percent for [NdnThept(COO)4]? (n=1, 2, or 3) in TRIS buffer. In 95 percent ethanol, quantum yields of NIR luminescence increase and are ?Yb=0.5 percent, 0.31 percent and 0.05 percent for [YbnThept(COO)4]? (n=1, 2, or 3), and ?Nd=0.40 percent, 0.45 percent and 0.12 percent for [NdnThept(COO)4]? (n=1, 2, or 3). All complexes are capable of generating 1O2 in 95 percent ethanol with ?1Ο2 efficiencies which range from 2 percent to 29 percent. These complexes are toxic to HeLa cells when irradiated with UV light (λexc=365 nm) for two minutes. IC50 values for the LnIII complexes are in the range 15.2–16.2 μm; the most potent compound is [Nd2Thept(COO)4]?. The cell death mechanisms are further explored using an Annexin V—propidium iodide assay which suggests that cell death occurs through both apoptosis and necrosis.
Synthesis of Homoditopic Ligands with an Incrementable Rodlike Backbone
Demay-Drouhard, Paul,Chamoreau, Lise-Marie,Guillot, Régis,Policar, Clotilde,Bertrand, Hélène C.
, p. 131 - 137 (2017)
We describe the synthesis of architectures that consist of a symmetrical rodlike oligo(phenylene-ethynylene) (OPE) backbone of incrementable length connected to a pair of classical ligands for metal coordination. OPE spacers decorated with various end gro
Efficient Synthesis of a Family of Bifunctional Chelators Based on the PCTA[12] Macrocycle Suitable for Bioconjugation
Leygue, Nadine,Enel, Morgane,Diallo, Abdel,Mestre-Voegtlé, Béatrice,Galaup, Chantal,Picard, Claude
, p. 2899 - 2913 (2019)
PCTA[12] is a 12-membered tetraaza-macrocyclic ligand that incorporates a pyridine unit within the macrocyclic ring and three acetate pendant arms. Unlike DOTA and NOTA chelators, PCTA is a recent entry to the field of macrocyclic polyaminocarboxylate ligands available to complex a variety of M2+/M3+ ions for biomedical applications such as diagnostic and radiotherapeutic. Despite the promising properties of its chelates, only a few of bifunctional chelating agents (BFCAs) derived from PCTA have been described so far. Based on our very recent methodology for the preparation of PCTA[12] itself, we report here the efficient synthesis of several BFCAs derived from PCTA bearing a free reactive function group, mainly devoted to conjugation purposes: ester, carboxylic acid, alcohol, aliphatic amine, aromatic amine, maleimide, bromo or azide functions. These functions were introduced either on the 4-position of the pyridine ring or on the methylene carbon atom of the central acetate chelating arm, while keeping the three carboxylate groups available for metal chelation. Moreover, two of these BFCAs-PCTA were used for conjugation with a tetrapeptide (cholecystokinin analogue), a bioactive molecule (biotin), or a solid support (silica gel).
The Synthesis of Group 10 and 11 Metal Complexes of 3,6,9-Trithia-1-(2,6)-pyridinacyclodecaphane and Their Use in A3-Coupling Reactions
Rasheed, Omer K.,Bawn, Carlo,Davies, David,Raftery, James,Vitorica-Yrzebal, I?igo,Pritchard, Robin,Zhou, Huimin,Quayle, Peter
, p. 5252 - 5261 (2017)
The reaction between 3,6,9-trithia-1(2,6)-pyridinacyclodecaphane and representative group 10 and 11 metal salts [Cu(NO3)2, NiCl2 or Ag(CF3CO2)] afforded 1:1 complexes, which in the case of CuII and AgI were characterised by single-crystal X-ray crystallography. The catalytic activity of these complexes in A3-coupling reactions between aldehydes, terminal alkynes and amines was assessed in both protic (water) and aprotic (toluene) media. These A3-reactions prove to be more efficient, proceed with lower catalyst loadings and with faster reaction rates, when conducted in a focused microwave reactor as compared to the same reactions promoted by standard, thermal, modes of activation.
The assembly of "s3N"-ligands decorated with an azo-dye as potential sensors for heavy metal ions
Rasheed,McDouall,Muryn,Raftery,Vitorica-Yrezabal,Quayle
, p. 5229 - 5239 (2017)
An "S3N-ligand azo-dye" conjugate has been synthesised with a view to the development of a sensor for heavy metal ions. Complexation of this system with Ag(i), Hg(ii) and Cu(ii) salts has been investigated and an X-ray structure has been obtained for a Hg(ii) complex. Complexation of the conjugated dye to these metals results in a bathochromic shift in the absorption maximum of the azo dye, an effect which is most pronounced for Cu(ii).
Site-specific labeling of proteins with a chemically stable, high-affinity tag for protein study
Yang, Yin,Li, Qing-Feng,Cao, Chan,Huang, Feng,Su, Xun-Cheng
, p. 1097 - 1103 (2013)
Site-specific labeling of proteins with paramagnetic lanthanides offers unique opportunities by virtue of NMR spectroscopy in structural biology. In particular, these paramagnetic data, generated by the anisotropic paramagnetism including pseudocontact shifts (PCS), residual dipolar couplings (RDC), and paramagnetic relaxation enhancement (PRE), are highly valuable in structure determination and mobility studies of proteins and protein-ligand complexes. Herein, we present a new way to label proteins in a site-specific manner with a high-affinity and chemically stable tag, 4-vinyl(pyridine-2,6-diyl) bismethylenenitrilo tetrakis(acetic acid) (4VPyMTA), through thiol alkylation. Its performance has been demonstrated in G47C and E64C mutants of human ubiquitin both in vitro and in a crowded environment. In comparison with the published tags, 4VPyMTA has several interesting features: 1)it has a very high binding affinity for lanthanides (higher than EDTA), 2)there is no heterogeneity in complexes with lanthanides, 3)the derivatized protein is stable and potentially applicable to the in situ analysis of proteins. NMR tag: Site-specific labeling of proteins with a high affinity, chemically stable lanthanide-binding tag for structural biology is presented (see figure). The protein-tag construct is an ideal system for the study of protein stability and self-assembly processes under in situ conditions. Copyright
Synthesis and Hydrolysis of 4-Chloro-PyMTA and 4-Iodo-PyMTA Esters and Their Oxidative Degradation with Cu(I/II) and Oxygen
Qi, Mian,Hülsmann, Miriam,Godt, Adelheid
supporting information, p. 3773 - 3784 (2016/10/30)
We disclose the syntheses of ethyl and tert-butyl esters of 4-chloro-PyMTA and 4-iodo-PyMTA from the commercially available chelidamic acid monohydrate in 39-67% overall yield. Additionally, ester hydrolyses with aqueous NaOH (ethyl esters) or trifluoroacetic acid (tert-butyl esters) are reported. The resulting materials contain 4-halo-PyMTA in mixture with partially deprotonated or partially protonated 4-halo-PyMTA. The ligand content expressed as the content of the common structural motifs of the present species, namely [PyMTA - 4 H+4- (basic hydrolysis) and PyMTA (acidic hydrolysis), was determined to be 90-94 wt % by1H NMR spectroscopy using maleic acid as an internal standard. The tert-butyl esters were easily hydrolyzed with aqueous alkali hydroxide, with a decreasing rate in the series NaOH, KOH, LiOH. This finding indicates a Lewis acid assisted ester cleavage with the Na+ ion fitting best to the multidentate ligand. Unexpectedly, PyMTA esters are incompatible with Cu(I/II) salts in the presence of oxygen. Under these conditions, one of the two aminomethyl groups is converted into a formyl group. This reaction not only limits the application of Cu(I/II)-catalyzed reactions but also necessitates trapping of any copper ions (e.g., with a metal ion scavenger) before the material is exposed to oxygen.
