The Palladium/norbornene catalytic system: novel synthetic applications and mechanistic insights

Novel synthetic applications of the Palladium/norbornene catalytic system are presented herein. Selective aromatic and aliphatic (or heteroaromatic) C-H bond activation in sequence allowed to present two new methods featuring intramolecular C-C bond formation. Development of one of this method employing alpha nitro esters allowed to find a novel method for the synthesys of aryl nitriles in the absence of a cyanide source. DFT calculations on this unsual reactivity proposes that the reaction occours through a Pd-mediated retro Mannich reaction. Mechanistic study on Pd/norbornene catalyzed sequences by DFT calculations allowed to enlight the role of substituents on the reacting aryl halides, which triggers the formation of Pd(IV) complexes responsible for selective biaryl synthesis

Oxidative dearomatization of phenols and polycyclic aromatics with hydrogen peroxide triggered by heterogeneous sulfonic acids

Suitable heterogeneous sulfonic acid derivatives ensure the smooth dearomatization of phenols and bare naphthalenes under mild conditions. The method uses hydrogen peroxide which is a clean oxidant, offering a convenient metal-free tool to access families of quinones derivatives in good yields and with low catalyst loading

Prognostic role of nutritional status in elderly patients hospitalized for COVID-19: a monocentric study

BackgroundSymptomatic severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection incidence is higher in the elderly patients. Pre-existing geriatric conditions such as comorbidity and frailty seem related to worse hospital outcomes.AimsTo assess the role of nutritional status as an independent prognostic factor for in-hospital death in elderly patients.MethodsConsecutive elderly patients (age > 65 years) hospitalized for novel coronavirus disease (COVID-19) were enrolled. Demographics, laboratory and comorbidity data were collected. Nutritional status was evaluated using the Geriatric Nutri-tional Risk Index (GNRI). Uni- and multivariate Cox regression analyses to evaluate predictors for in-hospital death were performed.ResultsOne hundred and nine hospitalized elderly patients (54 male) were consecutively enrolled. At univariate analysis, age (HR 1.045 [CI 1.008\u20131.082]), cognitive impairment (HR 1.949 [CI 1.045\u20133.364]), C-reactive protein (HR 1.004 [CI 1.011\u20131.078]), lactate dehydrogenases (HR 1.003 [CI 1.001\u20131.004]) and GNRI moderate\u2013severe risk category (HR 8.571 [CI 1.096\u201367.031]) were risk factors for in-hospital death, while albumin (HR 0.809 [CI 0.822\u20130.964]), PaO2/FiO2 ratio (HR 0.996 [CI 0.993\u20130.999]) and body mass index (HR 0.875 [CI 0.782\u20130.979]) were protective factors. Kaplan\u2013Meier survival curves showed a significative higher survival in patients without GNRI moderate or severe risk category (p = 0.0013).At multivariate analysis, PaO2/FiO2 ratio (HR 0.993 [CI 0.987\u20130.999], p = 0.046) and GNRI moderate\u2013severe risk category (HR 9.285 [1.183\u201372.879], p = 0.034) were independently associated with in-hospital death.ConclusionNutritional status assessed by GNRI is a significative predictor of survival in elderly patients hospitalized for COVID-19. The association between GNRI and PaO2/FiO2 ratio is a good prognostic model these patients

Ambient Synthesis of Tricyclic Naphthalenes via Stepwise Styryl-yne Dearomative Diels{ extendash}Alder Cyclization

A cascade of styrylynols promoted by MnO2 allows the synthesis of fused tricycles with a naphthalene core. The reaction occurs under ambient conditions, offering a practical synthetic tool because of the inexpensive and abundant manganese species. The method affords products through the sequential oxidation of a propargyl alcohol, stepwise Diels-Alder cyclization, and finally rearomatization. According to density functional theory, the usually unfavorable stepwise Diels-Alder mechanism is instead a general tool for eliciting otherwise challenging dearomative annulation

Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

Converting biomass into value-added chemicals holds the key to sustainable long-term carbon resource management. In this context, levulinic acid, which is easily obtained from cellulose, is valuable since it can be transformed into a variety of industrially relevant fine chemicals. Here we present a simple protocol for the selective esterification of levulinic acid using solid acid catalysts. Silica supported sulfonic acid catalysts operate under mild conditions and give good conversion and selectivity with stoichiometric amounts of alcohols. The sulfonic acid groups are tethered to the support using organic tethers. These tethers may help in preventing the deactivation of the active sites in the presence of water

Effects of zoledronic acid and dexamethasone on early phases of socket healing after tooth extraction in rats : a preliminary macroscopic and microscopic quantitative study

The exact pathogenesis of medication-related osteonecrosis of the jaw (MRONJ) is still unknown. The aim of this paper was to investigate the effects of zoledronic acid and dexamethasone on the early phases of socket healing in rats subjected to tooth extractions. Thirty male Sprague-Dawley rats were divided into 2 groups: pharmacologically treated group (T, n=20) and non-pharmacologically treated group (C, n=10). T group rats received 0.1 mg/Kg of zoledronic acid (ZOL) and 1 mg/Kg of dexamethasone (DEX) three times a week for 10 consecutive weeks. C group rats were infused with vehicle. After 9 weeks from the first infusion, first maxillary molars were extracted in each of the rats. Quantitative macroscopic and microscopic analysis was performed to evaluate socket healing 8 days after extraction. Pharmacologically treated rats showed significant inhibition of bone remodeling. Connective tissue/alveolar bone ratio, osteoclast number and woven bone deposition were significantly reduced in group T compared to group C. Conversely, the proportion of necrotic bone was higher in group T compared to group C (0.8% and 0.3%, respectively. P=0.031). ZOL plus DEX do not cause gross effects on socket healing at a macroscopic level. Our findings confirmed that exposure to ZOL plus DEX impairs alveolar wound repair. Inhibition of osteoclastic resorption of socket walls after tooth extraction and the inability to dispose of the necrotic bone may be considered the initial steps of MRONJ onset

“Bottled” Spiro-Doubly Aromatic Trinuclear [Pd2Ru]+ Complexes

Following an ongoing interest in the study of transition metal complexes with exotic bonding networks, we report herein the synthesis of a family of heterobimetallic triangular clusters involving Ru and Pd atoms. These are the first examples of trinuclear complexes combining these nuclei. Structural and bonding analyses revealed both analogies and unexpected differences for these [Pd2Ru]+ complexes compared to their parent [Pd3]+ peers. Noticeably, participation of the Ru atom in the π-aromaticity of the coordinated benzene ring makes the synthesized compound the second reported example of ‘bottled’ double aromaticity. This can also be referred to as spiroaromaticity due to the participation of Ru in two aromatic systems at a time. Moreover, the [Pd2Ru]+ kernel exhibits unprecedented orbital overlap of Ru dz2 AO and two Pd dxy or dx2−y2 AOs. The present findings reveal the possibility of synthesizing stable clusters with delocalized metal–metal bonding from the combination of non-adjacent elements of the periodic table which has not been reported previously

Evolution of Triangular All-Metal Aromatic Complexes from Bonding Quandaries to Powerful Catalytic Platforms

This manuscript describes an overview on the literature detailing the observation of trinuclear complexes that present delocalized metal–metal bonds similar to those of regular aromatics, which are formed combining main group elements. A particular emphasis is given to the structural and electronic features of aromatic clusters that are sufficiently stable to allow their isolation. In parallel to the description of their key bonding properties, the work presents reported catalytic applications of these complexes, which already span from elaborated C–C-forming cascades to highly efficient cross-coupling methods. These examples present peculiar aspects of the unique reactivity exerted by all-metal aromatic complexes, which can often be superior to their established, popular mononuclear peers in terms of chemoselectivity and chemical robustnes

Phase- and Stage-Related Proportions of T Cells Bearing the Transcription Factor FOXP3 Infiltrate Primary Melanoma

Although tumor-infiltrating lymphocytes (TILs) of primary cutaneous melanoma (PCM) include cytolytic T cells able to exert anti-PCM immunity, progression of PCM most frequently occurs, raising the hypothesis that the PCM microenvironment may also exert suppressive forces, for example, possibly developed by regulatory T (TREG) lymphocytes. The aim of this study was to investigate whether TILs of PCMs include lymphocytes bearing the transcription factor forkhead box protein P3 (FOXP3), which is the TREG lineage specification molecule in mice, and is debated to have a similar role in humans. Fourteen patients with PCM were selected, of which four had radial growth phase (RGP) stage I melanoma, five had vertical growth phase (VGP) stage I melanoma, and five had VGP stage III–IV melanoma. Formalin-fixed, paraffin-embedded sections were utilized for immunohistochemical single and double stainings. TILs of PCMs included FOXP3-bearing lymphocytes, which predominantly were CD20- and CD8-negative, but CD3-, CD4-, and CD25-positive, thus consistent with the standard immunophenotypical characteristics of “natural” TREG cells. Further, the proportions of FOXP3-bearing lymphocytes were higher in vertical than in RGP (P=0.001), as well as in late than in early melanoma stages (P<0.001). Should these FOXP3-bearing lymphocytes actually exert regulatory capabilities within the PCM microenvironment, they may suppress “in vivo” the local anti-PCM immune response, thus favoring melanoma progression

Real-Time On-Site Diagnosis of Quarantine Pathogens in Plant Tissues by Nanopore-Based Sequencing

Rapid and sensitive assays for the identification of plant pathogens are necessary for the effective management of crop diseases. The main limitation of current diagnostic testing is the inability to combine broad and sensitive pathogen detection with the identification of key strains, pathovars, and subspecies. Such discrimination is necessary for quarantine pathogens, whose management is strictly dependent on genotype identification. To address these needs, we have established and evaluated a novel all-in-one diagnostic assay based on nanopore sequencing for the detection and simultaneous characterization of quarantine pathogens, using Xylella fastidiosa as a case study. The assay proved to be at least as sensitive as standard diagnostic tests and the quantitative results agreed closely with qPCR-based analysis. The same sequencing results also allowed discrimination between subspecies when present either individually or in combination. Pathogen detection and typing were achieved within 13 min of sequencing owing to the use of an internal control that allowed to stop sequencing when sufficient data had accumulated. These advantages, combined with the use of portable equipment, will facilitate the development of next-generation diagnostic assays for the efficient monitoring of other plant pathogens