Search results for "ligands"
showing 10 items of 721 documents
Off-Target-Based Design of Selective HIV-1 PROTEASE Inhibitors
2021
The approval of the first HIV-1 protease inhibitors (HIV-1 PRIs) marked a fundamental step in the control of AIDS, and this class of agents still represents the mainstay therapy for this illness. Despite the undisputed benefits, the necessary lifelong treatment led to numerous severe side-effects (metabolic syndrome, hepatotoxicity, diabetes, etc.). The HIV-1 PRIs are capable of interacting with “secondary” targets (off-targets) characterized by different biological activities from that of HIV-1 protease. In this scenario, the in-silico techniques undoubtedly contributed to the design of new small molecules with well-fitting selectivity against the main target, analyzing possible undesirabl…
Ligand density on nanoparticles: A parameter with critical impact on nanomedicine
2019
Nanoparticles modified with ligands for specific targeting towards receptors expressed on the surface of target cells are discussed in literature towards improved delivery strategies. In such concepts the ligand density on the surface of the nanoparticles plays an important role. How many ligands per nanoparticle are best for the most efficient delivery? Importantly, this number may be different for in vitro and in vivo scenarios. In this review first viruses as "biological" nanoparticles are analyzed towards their ligand density, which is then compared to the ligand density of engineered nanoparticles. Then, experiments are reviewed in which in vitro and in vivo nanoparticle delivery has b…
Structural analysis of Cu(II) ligation to the 5'-GMP nucleotide by pulse EPR spectroscopy.
2007
JBIC Journal of Biological Inorganic Chemistry, 12 (6)
Crystal and solution structures of di-n-butyltin(IV) complexes of 5-[(E)-2-(4-methoxyphenyl)-1-diazenyl]quinolin-8-ol and benzoic acid derivatives: E…
2009
Abstract Reactions of nBu2SnCl(L1) (1), where L1 = acid residue of 5-[(E)-2-(4-methoxyphenyl)-1-diazenyl]quinolin-8-ol, with various substituted benzoic acids in refluxing toluene, in the presence of triethylamine, yielded dimeric mixed ligand di-n-butyltin(IV) complexes of composition [nBu2Sn(L1)(L2–6)]2 where L2 = benzene carboxylate (2), L3 = 2-[(E)-2-(2-hydroxy-5-methylphenyl)-1-diazenyl]benzoate (3), L4 = 5-[(E)-2-(4-methylphenyl)-1-diazenyl]-2-hydroxybenzoate (4), L5 = 2-{(E)-4-hydroxy-3-[(E)-4-chlorophenyliminomethyl]-phenyldiazenyl}benzoate (5) and L6 = 2-[(E)-(3-formyl-4-hydroxyphenyl)-diazenyl]benzoate (6). All complexes (1–6) have been characterized by elemental analyses, IR, 1H,…
Intermolecular oxidative dehydrogenative 3,3′-coupling of benzo[b]furans and benzo[b]thiophenes promoted by DDQ/H+: total synthesis of shandougenine B
2016
With an excess of a strong acid, 2,3-dichloro-5,6-dicyano-1,4-quinone (DDQ) is shown to promote metal-free intermolecular oxidative dehydrogenative (ODH) 3,3'-coupling of 2-aryl-benzo[b]furans and 2-aryl-benzo[b]thiophenes up to 92% yield as demonstrated with 9 substrates. Based on the analysis of oxidation potentials and molecular orbitals combined with EPR, NMR and UV-Vis observations, the studied reaction is initiated by a DDQ-substrate charge transfer complex and presumably proceeds via oxidation of the substrate into an electrophilic radical cation that further reacts with another molecule of a neutral substrate. The coupling reactivity can easily be predicted from the oxidation potent…
Synthesis, characterization, and cytotoxic activity of copper(II) and platinum(II) complexes of 2-benzoylpyrrole and X-ray structure of bis[2-benzoyl…
2004
Copper(II) and platinum(II) complexes of 2-benzoylpyrrole (2-BZPH) were synthesized and characterized with IR, 1 H and 1 3 C NMR spectroscopies and coordination geometry with ligands arranged in transoid fashion. The crystal structure of [Cu I I (2-BZP) 2 ] was determined by X-ray diffraction. Death of complex treated Jurkat cells was measured by flow cytometry. The bis-chelate complexes [Cu I I (2-BZP) 2 ] and [Pt I I (2-BZP) 2 ] adopt square-planar coordination geometry with ligands, arranged in transoid fashion. Concentrations of 1-10 μM Platinum(II) complexes reduced cell survival from 100% to 20%, in contrast to the copper(II) complex which caused no cell death at a concentration of 10…
Mossbauer spectroscopic study of the thermal spin crossover in [Fe(II)(isoxazole)(6)](ClO(4))(2)
2008
The (57)Fe Mossbauer spectroscopy of mononuclear [Fe(II)(isoxazole)(6)](ClO(4))(2) has been studied to reveal the thermal spin crossover of Fe(II) between low-spin (S = 0) and high-spin (S = 2) states.Temperature-dependent spin transition curves have been constructed with the least-square fitted data obtained from the Mossbauer spectra measured at various temperatures between 84 and 270 K during a cooling and heating cycle. This compound exhibits an unusual temperature-dependent spin transition behaviour with T(C)(down arrow) = 223 and T(C)(up arrow) = 213 K occurring in the reverse order in comparison to those observed in SQUID observation and many other spin transition compounds. The comp…
Stabilized Naked Sub-nanometric Cu Clusters within a Polymeric Film Catalyze C-N, C-C, C-O, C-S, and C-P Bond-Forming Reactions
2015
[EN] Sub-nanometric Cu clusters formed by endogenous reduction of Cu salts and Cu nanoparticles are active and selective catalysts for C−N, C−C, C−O, C−S, and C−P bond-forming reactions. Sub-nanometric Cu clusters have also been generated within a polymeric film and stored with full stability for months. In this way, they are ready to be used on demand and maintain high activity (TONs up to 104 ) and selectivity for the above reactions. A potential mechanism for the formation of the sub-nanometric clusters and their electronic nature is presented.
Coordination properties of adenosine-5'-monophosphate and related ligands towards Me2Sn(IV)2+ in aqueous solution.
2002
Abstract The coordination of Me 2 Sn(IV) 2+ to adenosine-5′-monophosphate (AMP) and the related compounds d -ribose-5-phosphate (R5P), d -glucose-1-phosphate (G1P) and d -glucose-6-phosphate (G6P) in aqueous solution was investigated by means of potentiometric titration, and 1 H-, 31 P-NMR and Mossbauer spectroscopic methods in the pH range 2–11 ( I =0.1 M NaClO 4 , 298 K). The complex of AMP and Me 2 Sn(IV) 2+ precipitated at low pH was characterised by elemental analysis, FT-IR and Mossbauer spectroscopic methods. From a comparison of the p K values obtained in the presence and absence of metal ion and the stability constants for the different systems, the coordination of {N} is excluded,…
Safety and Activity of the First-in-Class Sym004 Anti-EGFR Antibody Mixture in Patients with Refractory Colorectal Cancer
2015
Abstract Tumor growth in the context of EGFR inhibitor resistance may remain EGFR-dependent and is mediated by mechanisms including compensatory ligand upregulation and de novo gene alterations. Sym004 is a two-antibody mixture targeting nonoverlapping EGFR epitopes. In preclinical models, Sym004 causes significant EGFR internalization and degradation, which translates into superior growth inhibition in the presence of ligands. In this phase I trial, we observed grade 3 skin toxicity and hypomagnesemia as mechanism-based dose-limiting events during dose escalation. In dose-expansion cohorts of 9 and 12 mg/kg of Sym004 weekly, patients with metastatic colorectal cancer and acquired EGFR inhi…