- Pyrene-appended bipyridine hydrazone ligand as a turn-on sensor for Cu2+ and its bioimaging application
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A pyrene-appended bipyridine hydrazone-based ligand, HL, was synthesized and characterized by spectroscopic methods. Upon complexation with Cu(ii), HL formed a hexanuclear paddlewheel metal-organic macrocycle (MOM) via self-assembly with a high association constant with the molecular formula of [Cu6L6(NO3)6]. Intermolecular and intramolecular π-π interactions were demonstrated in this hexanuclear Cu(ii) complex. Further, it was observed that HL had the potential to detect a trace level of Cu(ii) ion selectively among a wide range of biologically relevant metal ions in aqueous medium at physiological pH. Using HL, it was feasible to sense copper(ii) ions in living cells due to its good cell permeability and high solubility under physiological conditions along with its high IC50 value. The low detection limit, high sensitivity and good reproducibility make this Cu-sensor very promising. The complex (MOM) formed between the ligand and Cu(ii) was found to be 1:1 on the basis of fluorescence titrations and was confirmed by ESI-MS. Moreover, single-crystal study of the hexanuclear self-assembled fluorescent species provided better insight into its chemistry, e.g. coordination environment and binding mode, unlike most of the metal sensors due to the lack of a single-crystal structure of the metal sensor complex. Cytotoxicity assay and bioimaging were performed in living cells (Vero cells), giving green fluorescent images. Fluorescence lifetime measurements and theoretical calculations were carried out. The morphology and topographic details on the surface of the metal-organic macrocycle (MOM) were studied by field-emission scanning electron microscopy (FESEM).
- Hossain, Sayed Muktar,Prakash, Ved,Mamidi, Prabhudutta,Chattopadhyay, Soma,Singh, Akhilesh Kumar
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p. 3646 - 3658
(2020/02/04)
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- IMMUNOSUPPRESSIVE AGENTS
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Provided herein is a compound having the Formula 1, all of its related stereoisomers and their pharmaceutically acceptable salts with immunosuppressive property and process for preparation thereof. The said molecule provides potent anti-proliferative activity in lymphocyte proliferation assay and in mouse skin graft rejection assay. Further, the said molecule is a valuable lead compound in development of improved immunosuppressive agents.
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Page/Page column 29-30
(2018/08/20)
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- Synthesis of 2,2-Bipyridines via Suzuki-Miyaura Cross-Coupling
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For a long time, the Suzuki-Miyaura cross-coupling reaction could not be used for the synthesis of 2,2′-bipyridines due to the lack of sufficiently stable 2-pyridylboron compounds. Stabilized 2-pyridylboronic acid esters recently developed by Hodgson, however, were found to be ideally suited for this purpose. Two general protocols could be developed and demonstrated to be valuable alternatives, which can be used very efficiently for the synthesis of functionalized 2,2-bipyridines.
- Guetz, Christoph,Luetzen, Arne
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experimental part
p. 85 - 90
(2010/04/29)
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- Preparation of non-symmetrical 2,3-bis-(2,2'-oligopyridyl)pyrazines via 1,2-disubstituted ethanones
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Sequential oxidation of the condensation products between alkyl 2,2'- oligopyridyl carboxylates and 6-methyl pyridine homologues with m-CPBA, then iodine affords the corresponding mixed α-diketones. These compounds are readily transformed into the respective mixed bis-oligopyridyl pyrazines, a class of compounds of interest for supramolecular chemistry.
- Heirtzler, Fenton R.
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p. 1203 - 1206
(2007/10/03)
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- Regioselective functionalization of 2,2′-bipyridine and transformations into unsymmetric ligands for coordination chemistry
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Novel synthetic strategies for a series of unsymmetrically substituted 2,2′-bipyridines have been developed. These bipyridines have found use in some novel homoleptic and heteroleptic ruthenium(II) complexes. Two methods for regiochemical control of nucleophilic addition to bpy have been explored: (i) mono N-oxidation followed by cyanation and subsequent hydrolysis gave 6-carboxy-2,2′-bipyridine (4); (ii) mono N-methylation followed by the conversion into 6-bromo-2,2′-bipyridine (12) and subsequent nucleophilic addition of lithioacetonitrile followed by hydrolysis of 6-cyanomethyl-2,2′-bipyridine (8) gave the homologous 2,2′-bipyridine-6-acetic acid (9). An established method of regioselective mono-ring alkylation of bpy using methyllithium yielded 6-methyl-2,2′-bipyridine (14), and the generation of the anion of 14 and subsequent addition to a chloromethyl oxazoline was applied to synthesize a second homologue, methyl 2,2′-bipyridine-6-propanoate (16). Structural determinations using 1H, 13C and 2D NMR spectroscopy permitted complete assignments of all signals in the 1H NMR spectra. Acta Chemica Scandinavica 1998.
- Norrby, Thomas,Boerje, Anna,Zhang, Lian,Akermark, Bjoern
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