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Chimia 2012Tin-free radical hydroxymethylations of haloalkanes using CO and HCHO as a C1 unit proceed efficiently in the presence of borohydrides as radical mediators. In the... (Review)
Review
Tin-free radical hydroxymethylations of haloalkanes using CO and HCHO as a C1 unit proceed efficiently in the presence of borohydrides as radical mediators. In the approach using CO, the formation of aldehydes by radical carbonylation and their subsequent reduction by hydrides lead to alcohols. On the other hand, the use of formaldehyde is more straightforward, in which the key reaction is alkyl radical addition to formaldehyde to give alkoxy radical, which abstracts hydrogen from borohydride reagents. The cascade sequences were observed in the reaction of cholesteryl bromide with HCHO, which displays the diverse applications of HCHO in radical chemistry.
Topics: Borohydrides; Carbon Monoxide; Formaldehyde; Free Radicals; Hydrocarbons, Halogenated; Methylation; Molecular Structure
PubMed: 22871277
DOI: 10.2533/chimia.2012.372 -
Journal of the American Chemical Society May 2022Carboranes represent a class of compounds with increasing therapeutic potential. However, few general approaches to readily embed carboranes into small molecules,...
Carboranes represent a class of compounds with increasing therapeutic potential. However, few general approaches to readily embed carboranes into small molecules, peptides, and proteins are available. We report a strategy based on palladium-mediated C-X (X = C, S, and N) bond formation for the installation of carborane-containing moieties onto small molecules and peptides. We demonstrate the ability of Pd-based reagents with appropriate ligands to overcome the high hydrophobicity of the carborane group and enable chemoselective conjugation of cysteine residues at room temperature in aqueous buffer. Accordingly, carboranes can be efficiently installed on proteins by employing a combination of a bis-sulfonated biarylphosphine-ligated Pd reagent in an aqueous histidine buffer. This method is successfully employed on nanobodies, a fully synthetic affibody, and the antibody therapeutics trastuzumab and cetuximab. The conjugates of the affibody Z and the trastuzumab antibody retained binding to their target antigens. Conjugated proteins maintain their activity in cell-based functional assays in HER2-positive BT-474 cell lines. This approach enables the rapid incorporation of carborane moieties into small molecules, peptides, and proteins for further exploration in boron neutron capture therapy, which requires the targeted delivery of boron-dense groups.
Topics: Boranes; Palladium; Peptides; Proteins; Trastuzumab
PubMed: 35438502
DOI: 10.1021/jacs.2c01932 -
Molecules (Basel, Switzerland) Dec 2019Hydrogen technology has become essential to fulfill our mobile and stationary energy needs in a global low-carbon energy system. The non-renewability of fossil fuels and... (Review)
Review
Hydrogen technology has become essential to fulfill our mobile and stationary energy needs in a global low-carbon energy system. The non-renewability of fossil fuels and the increasing environmental problems caused by our fossil fuel-running economy have led to our efforts towards the application of hydrogen as an energy vector. However, the development of volumetric and gravimetric efficient hydrogen storage media is still to be addressed. LiBH is one of the most interesting media to store hydrogen as a compound due to its large gravimetric (18.5 wt.%) and volumetric (121 kgH/m) hydrogen densities. In this review, we focus on some of the main explored approaches to tune the thermodynamics and kinetics of LiBH: (I) LiBH + MgH destabilized system, (II) metal and metal hydride added LiBH, (III) destabilization of LiBH by rare-earth metal hydrides, and (IV) the nanoconfinement of LiBH and destabilized LiBH hydride systems. Thorough discussions about the reaction pathways, destabilizing and catalytic effects of metals and metal hydrides, novel synthesis processes of rare earth destabilizing agents, and all the essential aspects of nanoconfinement are led.
Topics: Borohydrides; Catalysis; Hydrogen; Kinetics; Lithium Compounds; Magnesium Compounds; Metals; Nanostructures; Particle Size; Thermodynamics
PubMed: 31906111
DOI: 10.3390/molecules25010163 -
Journal of Molecular Biology May 2016Elongation factor G (EF-G) is a universally conserved translational GTPase that promotes the translocation of tRNA and mRNA through the ribosome. EF-G binds to the...
Elongation factor G (EF-G) is a universally conserved translational GTPase that promotes the translocation of tRNA and mRNA through the ribosome. EF-G binds to the ribosome in a GTP-bound form and subsequently catalyzes GTP hydrolysis. The contribution of the ribosome-stimulated GTP hydrolysis by EF-G to tRNA/mRNA translocation remains debated. Here, we show that while EF-G•GDP does not stably bind to the ribosome and induce translocation, EF-G•GDP in complex with phosphate group analogs BeF3(-) and AlF4(-) promotes the translocation of tRNA and mRNA. Furthermore, the rates of mRNA translocation induced by EF-G in the presence of GTP and a non-hydrolyzable analog of GTP, GDP•BeF3(-) are similar. Our results are consistent with the model suggesting that GTP hydrolysis is not directly coupled to mRNA/tRNA translocation. Hence, GTP binding is required to induce the activated, translocation-competent conformation of EF-G while GTP hydrolysis triggers EF-G release from the ribosome.
Topics: Aluminum Compounds; Boranes; Fluorides; GTP Phosphohydrolases; Guanosine Triphosphate; Hydrolysis; Peptide Elongation Factor G; Phosphates; Protein Biosynthesis; RNA, Messenger; RNA, Transfer; Ribosomes
PubMed: 27063503
DOI: 10.1016/j.jmb.2016.03.032 -
Molecules (Basel, Switzerland) May 2023Traditionally, drugs were obtained by extraction from medicinal plants, but more recently also by organic synthesis. Today, medicinal chemistry continues to focus on... (Review)
Review
Traditionally, drugs were obtained by extraction from medicinal plants, but more recently also by organic synthesis. Today, medicinal chemistry continues to focus on organic compounds and the majority of commercially available drugs are organic molecules, which can incorporate nitrogen, oxygen, and halogens, as well as carbon and hydrogen. Aromatic organic compounds that play important roles in biochemistry find numerous applications ranging from drug delivery to nanotechnology or biomarkers. We achieved a major accomplishment by demonstrating experimentally/theoretically that boranes, carboranes, as well as metallabis(dicarbollides), exhibit global 3D aromaticity. Based on the stability-aromaticity relationship, as well as on the progress made in the synthesis of derivatized clusters, we have opened up new applications of boron icosahedral clusters as key components in the field of novel healthcare materials. In this brief review, we present the results obtained at the Laboratory of Inorganic Materials and Catalysis (LMI) of the Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) with icosahedral boron clusters. These 3D geometric shape clusters, the semi-metallic nature of boron and the presence of -cluster hydrogen atoms that can interact with biomolecules through non-covalent hydrogen and dihydrogen bonds, play a key role in endowing these compounds with unique properties in largely unexplored (bio)materials.
Topics: Boron; Nanomedicine; Boranes; Pharmaceutical Preparations; Hydrogen
PubMed: 37298925
DOI: 10.3390/molecules28114449 -
FEBS Letters Aug 1974
Topics: Bacterial Proteins; Binding Sites; Borohydrides; Halobacterium; Hydroxylamines; Kinetics; Light; Membranes; Protein Binding; Retinal Pigments; Rhodopsin; Spectrophotometry; Spectrophotometry, Ultraviolet; Temperature; Time Factors; Ultracentrifugation
PubMed: 4415495
DOI: 10.1016/0014-5793(74)81153-1 -
Clinical and Experimental Immunology Feb 2012Carbon monoxide (CO) is produced during the catabolism of free haem, catalyzed by haem oxygenase (HO) enzymes, and its physiological roles include vasodilation,... (Review)
Review
Carbon monoxide (CO) is produced during the catabolism of free haem, catalyzed by haem oxygenase (HO) enzymes, and its physiological roles include vasodilation, neurotransmission, inhibition of platelet aggregation and anti-proliferative effects on smooth muscle. In vivo preclinical studies have shown that exogenously administered quantities of CO may represent an effective treatment for conditions characterized by a dysregulated immune response. The carbon monoxide-releasing molecules (CORMs) represent a group of compounds capable of carrying and liberating controlled quantities of CO in the cellular systems. This review covers the physiological and anti-inflammatory properties of the HO/CO pathway in the central nervous system. It also discusses the effects of CORMs in preclinical models of inflammation. The accumulating data discussed herein support the possibility that CORMs may represent a novel class of drugs with disease-modifying properties in multiple sclerosis.
Topics: Animals; Anti-Inflammatory Agents; Autoimmunity; Boranes; Carbon Monoxide; Carbonates; Cardiotonic Agents; Cytokines; Drug Evaluation, Preclinical; Encephalomyelitis, Autoimmune, Experimental; Guanylate Cyclase; Heme; Heme Oxygenase (Decyclizing); Heme Oxygenase-1; Humans; Inflammation; Multiple Sclerosis; Neuroimmunomodulation; Organometallic Compounds; Oxidation-Reduction; Receptors, Cytoplasmic and Nuclear; Signal Transduction; Soluble Guanylyl Cyclase; Vasodilator Agents
PubMed: 22235993
DOI: 10.1111/j.1365-2249.2011.04491.x -
Sensors (Basel, Switzerland) Jul 2021This work describes a new method for determining K concentration, [K], in blood plasma using a smartphone with a custom-built optical attachment. The method is based on...
This work describes a new method for determining K concentration, [K], in blood plasma using a smartphone with a custom-built optical attachment. The method is based on turbidity measurement of blood plasma solutions in the presence of sodium tetraphenylborate, a known potassium precipitating reagent. The images obtained by a smartphone camera are analyzed by a custom image-processing algorithm which enables the transformation of the image data from RGB to HSV color space and calculation of a mean value of the light-intensity component (V). Analysis of images of blood plasma containing different amounts of K reveal a correlation between V and [K]. The accuracy of the method was confirmed by comparing the results with the results obtained using commercial ion-selective electrode device (ISE) and atomic absorption spectroscopy (AAS). The accuracy of the method was within ± 0.18 mM and precision ± 0.27 mM in the [K] range of 1.5-7.5 mM when using treated blood plasma calibration. Spike tests on a fresh blood plasma show good correlation of the data obtained by the smartphone method with ISE and AAS. The advantage of the method is low cost and integration with a smartphone which offers possibility to measure [K] on demand and in remote areas where access to hospitals is limited.
Topics: Ion-Selective Electrodes; Plasma; Potassium; Smartphone; Tetraphenylborate
PubMed: 34300494
DOI: 10.3390/s21144751 -
Environmental Health Perspectives Nov 1994The amine-carboxyborane derivatives were shown to be effective antineoplastic/cytotoxic agents with selective activity against single-cell and solid tumors derived from... (Review)
Review
The amine-carboxyborane derivatives were shown to be effective antineoplastic/cytotoxic agents with selective activity against single-cell and solid tumors derived from murine and human leukemias, lymphomas, sarcomas, and carcinomas. The agents inhibited DNA and RNA synthesis in preference to protein synthesis in L1210 lymphoid leukemia cells. Inosine-monophosphate dehydrogenase apparently is a target site of the compounds; similar effects on phosphoribosyl-pyrophosphate amido transferase, orotidine-monophosphate decarboxylase, and both nucleoside and nucleotide kinases were observed. Deoxyribonucleotide pool levels were reduced in the cells; DNA strand scission was observed with the agents. In rodents, the amine carboxyboranes were potent hypolipidemic agents, lowering both serum cholesterol and triglyceride concentrations, in addition to lowering cholesterol content of very low-density lipoprotein and low-density lipoprotein (LDL) and elevating high-density lipoprotein (HDL) cholesterol concentrations. De novo regulatory enzymes involved in lipid synthesis were also inhibited (e.g., hypocholesterolemic 3-hydroxy-3-methyl-Coenzyme A reductase, acyl-Coenzyme A cholesterol acyltransferase, and sn-glycerol-3-phosphate acyltransferase). Concurrently, the agents modulated LDL and HDL receptor binding, internalization, and degradation, so that less cholesterol was delivered to the plaques and more broken down from esters and conducted to the liver for biliary excretion. Tissue lipids in the aorta wall of the rat were reduced and fewer atherosclerotic morphologic lesions were present in quail aortas after treatment with the agents. Cholesterol resorption from the rat intestine was reduced in the presence of drug. Genetic hyperlipidemic mice demonstrated the same types of reduction after treatment with the agents. The agents would effectively lower lipids in tissue based on the inhibition of regulatory enzymes in pigs. These findings should help improve domestic meat supplies from fowl and pigs. The amine-carboxyboranes were effective anti-inflammatory agents against septic shock, induced edema, pleurisy, and chronic arthritis at 2.5 to 8 mg/kg. Lysosomal and proteolytic enzyme activities were also inhibited. More significantly, the agents were dual inhibitors of prostaglandin cyclooxygenase and 5'-lipoxygenase activities. These compounds also affected cytokine release and white cell migration. Subsequent studies showed that the amine-carboxyboranes were potent anti-osteoporotic agents reducing calcium resorption as well as increasing calcium and proline incorporation into mouse pup calvaria and rat UMR-106 collagen.
Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antineoplastic Agents; Boranes; Humans; Hyperlipidemias; Hypolipidemic Agents; Inflammation; Neoplasms; Obesity
PubMed: 7889876
DOI: 10.1289/ehp.94102s721 -
Molecules (Basel, Switzerland) Jun 2020Thermodynamic hydricity (HDA) determined as Gibbs free energy (ΔG°[H]) of the H detachment reaction in acetonitrile (MeCN) was assessed for 144 small borane clusters...
Thermodynamic hydricity (HDA) determined as Gibbs free energy (ΔG°[H]) of the H detachment reaction in acetonitrile (MeCN) was assessed for 144 small borane clusters (up to 5 boron atoms), polyhedral -boranes dianions [BH], and their lithium salts Li[BH] (n = 5-17) by DFT method [M06/6-311++G(d,p)] taking into account non-specific solvent effect (SMD model). Thermodynamic hydricity values of diborane BH (HDA = 82.1 kcal/mol) and its dianion [BH] (HDA = 40.9 kcal/mol for Li[BH]) can be selected as border points for the range of borane clusters' reactivity. Borane clusters with HDA below 41 kcal/mol are strong hydride donors capable of reducing CO (HDA = 44 kcal/mol for HCO), whereas those with HDA over 82 kcal/mol, predominately neutral boranes, are weak hydride donors and less prone to hydride transfer than to proton transfer (e.g., BH, BH, BH, etc.). The HDA values of -boranes are found to directly depend on the coordination number of the boron atom from which hydride detachment and stabilization of quasi-borinium cation takes place. In general, the larger the coordination number (CN) of a boron atom, the lower the value of HDA.
Topics: Acetonitriles; Boranes; Hydrogen; Quantum Theory; Thermodynamics
PubMed: 32630429
DOI: 10.3390/molecules25122920