Search results for "Boronic Acid"
showing 10 items of 48 documents
Design of PNIPAAM covalently grafted on halloysite nanotubes as a support for metal-based catalysts
2016
A thermo-responsive polymer such as poly(N-isopropylacrylamide) (PNIPAAM) was covalently grafted on the external surface of halloysite nanotubes (HNTs) by means of microwave irradiation. This nanomaterial was used as a support and stabilizer for palladium nanoparticles. The obtained HNT–PNIPAAM/PdNPs was characterized by means of TGA, SEM, EDS and TEM analyses. The palladium content of the catalyst was estimated to be 0.4 wt%. The stability of the catalytic material at different temperatures (below and above the PNIPAAM lower critical solution temperature) was tested in the Suzuki reaction under microwave irradiation. In addition, TEM analysis after five consecutive runs was performed. The …
Investigation of fungicidal activity of 3-piperazine-bis(benzoxaborole) and its boronic acid analogue
2014
3-Piperazine-bis(benzoxaborole) and its bis(phenylboronic acid) analogue were investigated in terms of their fungicidal activity. The study was carried out against five filamentous fungi: Aspergillus terreus, Fusarium dimerum, Fusarium solani, Penicillium ochrochloron and Aspergillus niger. 3-Piperazine-bis(benzoxaborole) revealed higher inhibitory activity towards the examined strains than standard antibiotic (amphotericin B), whereas bis(phenylboronic acid) proved to be inactive. The study unequivocally showed that the presence of the heterocyclic benzoxaborole system is essential for antifungal action of the examined compounds.
5-Formyl-2-furanboronic acid at 100 K
2003
The furan ring in the title compound, C5H5BO4, is planar and each of the formyl and boronic groups makes a dihedral angle of ca 3° with this ring. The geometry of the furan ring is somewhat different to that found for substituted and unsubstituted furan structures. The molecules are connected to each other in the bc plane by C—H⋯O and O—H⋯O hydrogen bonds.
Bortezomib: a new pro-apoptotic agent in cancer treatment.
2010
Bortezomib is a proteasome inhibitor. It targets the ubiquitin-proteasome pathway with subsequent inhibition of the degradation of proteins involved in cell cycle regulation and cancer cell survival. The best known molecular mechanism concerns the inhibition of IkappaB breakdown and the related stabilization of NFkappaB, thus preventing its translocation to the nucleus for the activation of downstream pathways. Bortezomib is the only drug in this class which has been approved for clinical use. It has shown an efficient antitumor effect in a phase III clinical trial (APEX) involving relapsed multiple myeloma patients. Response rate, time to progression and overall survival have been improved…
Antifungal activity and tautomeric cyclization equilibria of formylphenylboronic acids
2019
2-Formylphenylboronic acid and four isomeric fluoro-2-formylphenylboronic acids have been found active against a series of fungal strains: Aspergillus, Fusarium, Penicillium and Candida. The level of antifungal activity was evaluated by agar diffusion tests as well as the determination of minimum inhibitory concentrations (MICs) by serial dilution method. Among the tested compounds, 4-fluoro-2-formylphenylboronic acid - an analogue of the known antifungal drug Tavaborole (AN2690) - proved to be the most potent antifungal agent. The tautomeric equilibrium leading to the formation of 3-hydroxybenzoxaboroles as well as the position of the fluorine substituent were revealed to play a crucial ro…
Intravenous injection of bortezomib, melphalan and dexamethasone in refractory and relapsed multiple myeloma
2013
Abstract Background A combination of bortezomib (1.3 mg/m2), melphalan (5 mg/m2), and dexamethasone (40 mg) (BMD), with all three drugs given as a contemporary intravenous administration, was retrospectively evaluated. Patients and methods Fifty previously treated (median 2 previous lines) patients with myeloma (33 relapsed and 17 refractory) were assessed. The first 19 patients were treated with a twice-a-week (days 1, 4, 8, 11, ‘base’ schedule) administration while, in the remaining 31 patients, the three drugs were administered once a week (days 1, 8, 15, 22, ‘weekly’ schedule). Results Side-effects were predictable and manageable, with prominent haematological toxicity, and a better tox…
A Colorimetric Probe for the Selective Detection of Norepinephrine Based on a Double Molecular Recognition with Functionalized Gold Nanoparticles
2019
[EN] A simple colorimetric probe for the selective and sensitive detection of neurotransmitter norepinephrine (NE), an important biomarker in the detection of tumors such as pheochromocytoma and paraganglioma, is described. The sensing strategy is based on the use of spherical gold nanoparticles functionalized with benzaldehyde and boronic acid-terminated moieties. A double molecular recognition involving on one hand the aromatic aldehyde and the aminoalcohol group of NE, and on the other hand the boronic acid and the catechol moiety of the neurotransmitter, results in analyte triggered aggregation of the gold nanoparticles, leading to a bathochromic shift of the SPR band in the UV-vis spec…
JNK and AP-1 mediate apoptosis induced by bortezomib in HepG2 cells via FasL/caspase-8 and mitochondria-dependent pathways
2006
The proteasome inhibitor bortezomib is an efficacious apoptotic agent in many tumor cells. This paper shows that bortezomib induced apoptosis in human hepatoma HepG2 cells associated with many modifications in the expression of survival or death factors. Although bortezomib increased the level of the protective factors HSP70 and HSP27, the effects of the drug that favour cell death were predominant. These events include accumulation of c-Jun, phospho-c-Jun and p53; increase in FasL level with activation of caspase-8; changes related to members of Bcl-2 family with increase in the level of pro-apoptotic members and decrease in that of anti-apoptotic ones; dissipation of mitochondrial potenti…
Gold-Catalyzed Suzuki Coupling of ortho -Substituted Hindered Aryl Substrates
2017
International audience; A method that allows hindered ortho-substituted aryl iodides to be efficiently coupled to phenylboronic acid using a gold-catalyzed C-C bond formation is presented. The use of a molecularly-defined dinuclear gold chloride catalytic precursor that is stabilized by a new tetradentate (N,N')-diamino-(P,P')-diphosphino ferrocene hybrid ligand in a Suzuki-type reaction is described for the first time. Electron-rich isopropyl groups on phosphorus were found essen-tial for a superior activity, while the performances of a set of analogous gold dinuclear complexes that were fully characterized by multinuclear NMR spectroscopy and XRD analysis, were investigated. Therefore, ar…
Targeting apoptosis in solid tumors: the role of bortezomib from preclinical to clinical evidence.
2007
The ubiquitin-proteasome pathway is the main proteolytic system present in the nucleus and cytoplasm of all eukaryotic cells. Apoptosis activation induced by ubiquitin-proteasome pathway inhibition makes the proteasome a new target of anticancer therapy. Bortezomib is the first proteasome inhibitor to be approved by the US FDA; in 2003 as a third line and in 2005 as a second line therapy for the treatment of multiple myeloma only. This review focuses on the use of bortezomib, not only in its therapeutic role but also, more specifically, in its biologic role and discusses the most recent applications of the drug in solid tumors, both at a preclinical and clinical level.