Tripodal ligands that can encapsulate single or multiple metal sites in -symmetric geometric configurations constitute valuable targets for novel catalysts. Of particular interest in ligand development are efforts toward incorporating apical elements that exhibit little if any electron donicity, to enhance the electrophilic nature of a positioned active oxidant (, metal-oxo, -nitrene). The tripodal ligand TMGtrphen-Arene has been synthesized, featuring an arene platform 1,3,5-substituted with phenylene arms possessing tetramethylguanidinyl (TMG) residues.
View Article and Find Full Text PDFProcessing tomato ( Mill.) is regarded amongst the most dominant horticultural crops globally. Yet, due to its elevated water and fertilization needs, its environmental footprint is significantly high.
View Article and Find Full Text PDFThe bipodal compounds [(TMGbiphen)Cu-NCMe](PF) (R = Me, Ar (4-CFPh-)) and [(TMGbiphen)Cu-I] have been synthesized with ligands that feature a diarylmethyl- and triaryl-amine framework and superbasic tetramethylguanidinyl residues (TMG). The cationic Cu(I) sites mediate catalytic nitrene-transfer reactions between the imidoiodinane PhI = NTs (Ts = tosyl) and a panel of styrenes in MeCN, to afford aziridines, demonstrating comparable reactivity profiles. The copper reagents have been further explored to execute C-H amination reactions with a variety of aliphatic and aromatic hydrocarbons and two distinct nitrene sources PhI = NTs and PhI = NTces (Tces = 2,2,2-trichloroethylsulfamate) in benzene/HFIP (10:2 v/v).
View Article and Find Full Text PDFIn the field of chiral recognition, chiral cyclic organic compounds, especially heterocyclic organic compounds, have attracted little attention and have been rarely studied as chiral substrates by means of H NMR spectroscopy. In this paper, enantiomers of thiohydantoin derivatives, representing typical five-membered ,-heterocycles, have been synthesized and utilized for assignment of absolute configuration and analysis of enantiomeric excess. All enantiomers have been successfully differentiated with the assistance of novel tetraaza macrocyclic chiral solvating agents (TAMCSAs) by H NMR spectroscopy.
View Article and Find Full Text PDFTobacco ( L.) is a major industrial crop that has being cultivated for centuries for the manufacturing of cigarettes, cigars, and other smoking products. Due to its negative effects on both human health and the environment, the European Union has adopted strict policies that aspire to reduce the consumption of tobacco.
View Article and Find Full Text PDFThe tripodal compounds [(TMGtrphen)M-solv](PF) (M = Mn, Fe, Co; solv = MeCN, DMF) and bipodal analogues [(TMGbiphen)M(NCMe)](PF) ( = 3 for Mn, Fe; = 2 for Co) and [(TMGbiphen)MCl] have been synthesized with ligands that feature a triaryl- or diarylmethyl-amine framework and superbasic tetramethylguanidinyl residues (TMG). The dicationic M(II) sites mediate catalytic nitrene-transfer reactions between the imidoiodinane PhI═NTs (Ts = tosyl) and a panel of styrenes in MeCN to afford aziridines and low yields of imidazolines (upon MeCN insertion) with an order of productivity that favors the bipodal over the tripodal reagents and a metal preference of Fe > Co ≥ Mn. In CHCl, the more acidic Fe(II) sites favor formation of 2,4-diaryl--tosylpyrrolidines by means of an in situ (3 + 2) cycloaddition of the initially generated 2-aryl--tosylaziridine with residual styrene.
View Article and Find Full Text PDFDue to the pressures imposed by climate change, the European Union (EU) has been forced to design several initiatives (the Common Agricultural Policy, the European Green Deal, Farm to Fork) to tackle the climate crisis and ensure food security. Through these initiatives, the EU aspires to mitigate the adverse effects of the climate crisis and achieve collective prosperity for humans, animals, and the environment. The adoption or promotion of crops that would facilitate the attaining of these objectives is naturally of high importance.
View Article and Find Full Text PDFBlack mustard [ (L.) Koch] is mainly cultivated as a seed crop, and there is a lack of information on biomass quality and its potential for animal feeding. A 2-year field experiment was set up in a split-plot design with 2 main plots (plant densities: 46 and 76 plants m), 4 sub-plots (fertilization levels: control, compost, urea with and without urease and nitrification inhibitors) and 3 replications for each treatment.
View Article and Find Full Text PDFTransmissible spongiform encephalopathies are incurable neurodegenerative diseases, associated with the conversion of the physiological prion protein to its disease-associated counterpart. Even though immunization against transmissible spongiform encephalopathies has shown great potential, immune tolerance effects impede the use of active immunization protocols for successful prophylaxis. In this study, we evaluate the use of trypanosomes as biological platforms for the presentation of a prion antigenic peptide to the host immune system.
View Article and Find Full Text PDFEnantiomers of a series of hydantoin derivatives were prepared from d- and l-amino acids with -tolyl isocyanate and 3,5-bis(trifluoromethyl)phenyl isocyanate as guests for chiral recognition by H NMR spectroscopy. Meanwhile, several tetraaza macrocyclic compounds were synthesized as chiral solvating agents from d-phenylalanine and (1,2)-(+)-1,2-diaminocyclohexane. An uncommon enantiomeric discrimination has been successfully established for hydantoin derivatives, representatives of five-membered N,N-heterocycles, in the presence of tetraaza macrocyclic chiral solvating agents (TAMCSAs) by means of H NMR spectroscopy.
View Article and Find Full Text PDFRecent research has highlighted the key role played by the electron affinity of the active metal-nitrene/imido oxidant as the driving force in nitrene additions to olefins to afford valuable aziridines. The present work showcases a library of Co(II) reagents that, unlike the previously examined Mn(II) and Fe(II) analogues, demonstrate reactivity trends in olefin aziridinations that cannot be solely explained by the electron affinity criterion. A family of Co(II) catalysts (17 members) has been synthesized with the assistance of a trisphenylamido-amine scaffold decorated by various alkyl, aryl, and acyl groups attached to the equatorial amidos.
View Article and Find Full Text PDFThe lockdown due to SARS-CoV-2 (COVID-19) pandemic forced both educators and students to swift and rely on digital technologies in order to ensure the successful completion of modules based on the official curriculum. Universities are still facing the challenging issue to offer high quality learning opportunities without risking participants' health. Towards that end, the current study presents a Hybrid Model under the Teaching Factory framework concept that has been successfully implemented and validated.
View Article and Find Full Text PDFEnantiomers of a few new amides containing two stereogenic centers have been derived from d- and l-α-amino acids as guests for chiral recognition by 1H NMR spectroscopy. A variety of chiral amides with two or more stereogenic centers often exist in the products of catalytic asymmetric synthesis, natural products or their total synthetic products, and chiral drugs. It would be a challenging and meaningful work to explore their chiral recognition.
View Article and Find Full Text PDFBackground: Bruton tyrosine kinase (BTK) inhibition targets B-cell and other non-T-cell immune cells implicated in the pathophysiology of pemphigus, an autoimmune disease driven by anti-desmoglein autoantibodies. Rilzabrutinib is a new reversible, covalent BTK inhibitor demonstrating preclinical efficacy as monotherapy in canine pemphigus foliaceus.
Objectives: To evaluate the efficacy and safety of oral rilzabrutinib in patients with pemphigus vulgaris in a multicentre, proof-of-concept, phase II trial.
Vision technologies are used in both industrial and smart city applications in order to provide advanced value products due to embedded self-monitoring and assessment services. In addition, for the full utilization of the obtained data, deep learning is now suggested for use. To this end, the current work presents the implementation of image recognition techniques alongside the original the quality assessment of a Parabolic Trough Collector (PTC) reflector surface to locate and identify surface irregularities by classifying images as either acceptable or non-acceptable.
View Article and Find Full Text PDFThe spin S=1/2 Kitaev honeycomb model has attracted significant attention since emerging candidate materials have provided a playground to test non-Abelian anyons. The Kitaev model with higher spins has also been theoretically studied, as it may offer another path to a quantum spin liquid. However, a microscopic route to achieve higher spin Kitaev models in solid state materials has not been rigorously derived.
View Article and Find Full Text PDFEnantiomers of a series of tripeptide derivatives with three stereogenic centers (±)-G1-G9 have been prepared from d- and l-α-amino acids as guests for chiral recognition by H NMR spectroscopy. In the meantime, a family of tetraaza macrocyclic chiral solvating agents (TAMCSAs) 1a-1d has been synthesized from d-phenylalanine and (1 S,2 S)-(+)-1,2-diaminocyclohexane. Discrimination of enantiomers of (±)-G1-G9 was carried out in the presence of TAMCSAs 1a-1d by H NMR spectroscopy.
View Article and Find Full Text PDFComments Mod Chem A Comments Inorg Chem
April 2016
Background: Cathelicidin has been correlated with the pathophysiology of atopic dermatitis (AD). An indirect correlation of vitamin D with the course of the disease has already been reported as it directly affects the levels of cathelicidin. The purpose of the present article is to investigate the impact of vitamin D supplementation on the course of AD.
View Article and Find Full Text PDFClin Cosmet Investig Dermatol
May 2017
Introduction: Morphea is an inflammatory skin disorder characterized by excessive collagen deposition. Although treatment algorithms for morphea subtypes have been suggested, no consistent recommendations are available. This study attempts to evaluate the clinical efficacy of methotrexate (MTX) as monotherapy in refractory generalized morphea.
View Article and Find Full Text PDFIn an effort to identify the optimal cyclodextrin (CD) host for delivery of penicillins to mammalian cells that will also offer protection against β-lactamase-induced hydrolysis, nuclear magnetic resonance (NMR) spectroscopy and isothermal titration calorimetry (ITC) have been employed to study the inclusion complexes formed in aqueous solution between designed CD derivatives and two aminopenicillins, ampicillin and amoxicillin, and two antistaphylococcal penicillins, methicillin and oxacillin. Anionic and cationic thioether-substituted-β- and -γCD derivatives were thus synthesized and compared with the neutral, parent CDs for complexation with the penicillins. The synthesized derivatives were shown to present ∼20% elongated cavity space in solution.
View Article and Find Full Text PDFH NMR spectroscopy is often used to discriminate enantiomers of chiral analytes and determine their enantiomeric excess (ee) by various chiral auxiliaries. In reported research, these studies were mainly focused on chiral discriminantion of chiral analytes with only one chiral center. However, many chiral compounds possessing two or more chiral centers are often found in natural products, chiral drugs, products of asymmetric synthesis and biological systems.
View Article and Find Full Text PDFIn the field of chiral recognition, reported chiral discrimination by H NMR spectroscopy has mainly focused on various chiral analytes with a single chiral center, regarded as standard chiral substrates to evaluate the chiral discriminating abilities of a chiral auxiliary. Among them, chiral α-hydroxy acids, α-amino acids and their derivatives are chiral organic molecules involved in a wide variety of biological processes, and also play an important role in the area of preparation of pharmaceuticals, as they are part of the synthetic process in the production of chiral drug intermediates and protein-based drugs. In this paper, several α-hydroxy acids and N-Ts-α-amino acids were used to evaluate the chiral discriminating abilities of tetraaza macrocyclic chiral solvating agents (TAMCSAs) 1a-1d by H NMR spectroscopy.
View Article and Find Full Text PDFControversy exists regarding the merits of exposure-based treatments for posttraumatic stress disorder (PTSD) versus a phased approach when prominent dissociative symptoms are present. The first aim of this study was to examine the degree to which diagnosing dissociation in two traumatized patients' vignettes influenced clinicians' preference for phase-oriented treatment and whether clinicians' treatment experience contributed to their treatment preference. The second aim was to assess the extent to which participants had observed traumatized patients worsen when treated with exposure therapy or phase-oriented therapy and whether the theoretical orientation and treatment experience of the clinician were related to the observed deterioration.
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