122 research outputs found

    Correction: Alkoxy radicals generation: facile photocatalytic reduction of N-alkoxyazinium or azolium salts

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    Correction for 'Alkoxy radicals generation: facile photocatalytic reduction of N-alkoxyazinium or azolium salts' by Luca Capaldo et al., Chem. Commun., 2019, DOI: 10.1039/c9cc00035f

    Visible Light Uranyl Photocatalysis: Direct C–H to C–C Bond Conversion

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    Uranyl nitrate hexahydrate performs as an efficient photocatalyst in the direct C–H to C–C bond conversion under blue light irradiation via hydrogen atom transfer (HAT). This uranyl salt enables th..

    Identifying Amidyl Radicals for Intermolecular C-H Functionalizations

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    Recent studies have demonstrated the capabilities of amidyl radicals to facilitate a range of intermolecular functionalizations of unactivated, aliphatic C-H bonds. Relatively little information is known regarding the important structural and electronic features of amidyl and related radicals that impart efficient reactivity. Herein, we evaluate a diverse range of nitrogen-centered radicals in unactivated, aliphatic C-H chlorinations. These studies establish the salient features of nitrogen-centered radicals critical to these reactions in order to expedite the future development of new site-selective, intermolecular C-H functionalizations

    Substituent effects on NMR spectroscopy of 2,2-dimethylchroman-4-one derivatives: Experimental and theoretical studies

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    The attribution of 1H and 13C NMR signals of a library of 5-, 6- and 7-substituted 2,2-dimethylchroman-4-one derivatives is reported. Substituent effects were interpreted in terms of the Hammett equation, showing a good correlation for carbons para- to the substituent group, not for the meta- ones. Similarly, the Lynch correlation shows the additivity of the substituent chemical shifts in the case of both H and C nuclei, again with the exception of the carbons in the meta- position. Density Functional Theory (DFT)-predicted 1H and 13C chemical shifts correspond closely with experimentally observed values, with some exceptions for C NMR data; however, the correlation is valid only for the aromatic moiety and cannot be extended to the heterocyclic ring of the chroman-4-one scaffold.Fil: Iguchi, Daniela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ravelli, Davide. Universita degli Studi di Pavia; ItaliaFil: Erra Balsells, Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Bonesi, Sergio Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

    Sunlight Photocatalyzed Regioselective β‐Alkylation and Acylation of Cyclopentanones.

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    Visible light induced direct β-C–H/C–C conversion of cyclopentanones was accomplished by using tetrabutylammonium decatungstate, TBADT, as the photocatalyst

    Site-Selective C–H Functionalization by Decatungstate Anion Photocatalysis: Synergistic Control by Polar and Steric Effects Expands the Reaction Scope

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    The synergistic control of the SH2 transition states of hydrogen abstraction by polar and steric effects provides a promising strategy in achieving site-selective C(sp3)–H functionalization under decatungstate anion photocatalysis. By using this photocatalytic approach, the C–H bonds of alkanes, alcohols, ethers, ketones, amides, esters, nitriles, and pyridylalkanes were functionalized site-selectively. In the remarkable case of a 2,4-disubstituted cyclohexanone bearing five methyl, five methylene, and three methine C–H bonds, one methine C–H bond in the isoamyl tether was selectively functionalized

    The Synthesis of Chiral Gamma-Lactones by Merging Decatungstate Photocatalysis with Biocatalysis

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    The implementation of light-driven catalytic processes in biocatalysis opens a golden window of opportunities. We hereby report the merging of photocatalytic C-C bond formation with enzymatic asymmetric reduction for the direct conversion of simple aldehydes and acrylates or unsaturated carboxylic acids into chiral ?-lactones. Tetrabutylammonium decatungstate (TBADT) is employed as the photocatalyst to trigger the hydroacylation of the starting olefins, yielding the corresponding keto esters/acids. Subsequently, an alcohol dehydrogenase converts the intermediate to the chiral alcohol, which undergoes lactonization to the desired ?-lactone. The photochemoenzymatic synthesis of aliphatic and aromatic ?-lactones was thereby achieved with up to >99 % ee  and >99 % yield. This synthesis highlights the power of building molecular complexity by merging photocatalysis with biocatalysis to access high-value added chiral compounds from simple, cheap and largely available starting materials

    Versatile Cross-Dehydrogenative Coupling of Heteroaromatics and Hydrogen Donors via Decatungstate Photocatalysis

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    A facile sunlight-induced derivatization of heteroaromatics via photocatalyzed C-H functionalization in amides, ethers, alkanes and aldehydes is described. Tetrabutylammonium decatungstate (TBADT) was used as the photocatalyst and allowed to carry out the process under mild conditions

    Proteomic profiling of extracellular vesicles in synovial fluid and plasma from Oligoarticular Juvenile Idiopathic Arthritis patients reveals novel immunopathogenic biomarkers

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    IntroductionNew early low-invasive biomarkers are demanded for the management of Oligoarticular Juvenile Idiopathic Arthritis (OJIA), the most common chronic pediatric rheumatic disease in Western countries and a leading cause of disability. A deeper understanding of the molecular basis of OJIA pathophysiology is essential for identifying new biomarkers for earlier disease diagnosis and patient stratification and to guide targeted therapeutic intervention. Proteomic profiling of extracellular vesicles (EVs) released in biological fluids has recently emerged as a minimally invasive approach to elucidate adult arthritis pathogenic mechanisms and identify new biomarkers. However, EV-prot expression and potential as biomarkers in OJIA have not been explored. This study represents the first detailed longitudinal characterization of the EV-proteome in OJIA patients.MethodsFourty-five OJIA patients were recruited at disease onset and followed up for 24 months, and protein expression profiling was carried out by liquid chromatography-tandem mass spectrometry in EVs isolated from plasma (PL) and synovial fluid (SF) samples.ResultsWe first compared the EV-proteome of SF vs paired PL and identified a panel of EV-prots whose expression was significantly deregulated in SF. Interaction network and GO enrichment analyses performed on deregulated EV-prots through STRING database and ShinyGO webserver revealed enrichment in processes related to cartilage/bone metabolism and inflammation, suggesting their role in OJIA pathogenesis and potential value as early molecular indicators of OJIA development. Comparative analysis of the EV-proteome in PL and SF from OJIA patients vs PL from age/gender-matched control children was then carried out. We detected altered expression of a panel of EV-prots able to differentiate new-onset OJIA patients from control children, potentially representing a disease-associated signature measurable at both the systemic and local levels with diagnostic potential. Deregulated EV-prots were significantly associated with biological processes related to innate immunity, antigen processing and presentation, and cytoskeleton organization. Finally, we ran WGCNA on the SF- and PL-derived EV-prot datasets and identified a few EV-prot modules associated with different clinical parameters stratifying OJIA patients in distinct subgroups.DiscussionThese data provide novel mechanistic insights into OJIA pathophysiology and an important contribution in the search of new candidate molecular biomarkers for the disease

    Claudin3 is localized outside the tight junctions in human carcinomas

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    Claudin3 is an integral component of the tight junction proteins in polarized epithelia. The expression of claudin3 was assessed in epithelial-derived tumors using Oncomine database. To determine the gene alteration during carcinogenesis, copy number alterations and mutations of claudin3 were evaluated using cBioPortal database. Claudin3 is overexpressed in several tumors including gynecological, bladder, breast and prostate carcinomas. 38% of the 163 evaluated studies show mutations and/or amplification of claudin3. 3D reconstruction of tissue samples following immunofluorescence analysis clearly demonstrated that, unlike in healthy tissues, claudin3 is mislocalized and unengaged in the formation of tight junction in tumor samples. These data strongly support the evaluation of unengaged claudin3 as a target for the development of novel diagnostic probes, optical approaches for real time detection of tumoral tissues during surgery, and target therapeutic drugs
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