Catalytic hydrosilylation of 1,1-disubstituted enamides is one of the most challenging and synthetically useful processes in organosilicon chemistry and asymmetric catalysis. Herein, we report a rhodium-catalyzed enantioselective hydrosilylation of α-arylenamides with substituted hydrosilanes with the aid of chiral P-ligand, including newly developed spirophosphite ligands, giving various chiral β-silylated amides in excellent yields with good to excellent enantioselectivities (98:2 er after recrystallization). In addition, chiral β-silylated amines can be obtained by further functionalization of the hydrosilylation product.
View Article and Find Full Text PDFExposure to phytotoxins that are present in imported ornamental or native plants is an important cause of animal disease. Factors such as animal behaviors (especially indoor pets), climate change, and an increase in the global market for household and ornamental plants led to the appearance of new, previously unreported plant poisonings in Europe. This has resulted in an increase in the incidence of rarely reported intoxications.
View Article and Find Full Text PDFWe report a rhodium-catalyzed anti-Markovnikov regioselective hydrosilylation of trifluoromethylalkenes with substituted silanes giving various α-trifluoromethyl-β-silanes in good to excellent yields. The hydrogenation products were obtained via the same key intermediate treated with methanol as a protic solvent. Both transformations had a broad functional tolerance and were expected to facilitate the construction of complex α-trifluoromethyl compounds.
View Article and Find Full Text PDF-Bromofluoroalkenes have been combined with phosphite under irradiation, in the presence of Fukuzumi's catalyst (9-mesityl-10-methylacridinium perchlorate) as an organic photocatalyst, to provide valuable -fluorophosphonate derivatives, known as stable mimics of phosphates. The desired products were obtained in good to excellent yields, and the reaction showed very good chemical tolerance.
View Article and Find Full Text PDFA series of mixed matrix membranes containing poly (ether-block-amide) Pebax 1657 as matrix and polyethylene glycol (PEG) and Zeolitic Imidazolate Framework-8 (ZIF-8) as additives, were prepared and tested for CO separation. The membranes were prepared by solvent evaporation method and were characterized by TGA, DSC, SEM, and gas permeation measurements. The effects of PEG and its molecular weight, and the percentage of ZIF-8 into Pebax matrix were investigated.
View Article and Find Full Text PDFA series of ferrocenyl-containing γ-hydroxy-γ-lactam tetramates were prepared in 2-3 steps through ring opening-ring closure (RORC) process of γ-ylidene-tetronate derivatives in the presence of ferrocenyl alkylamines. The compounds were screened in vitro for their antiplasmodial activity against chloroquine-sensitive (3D7) and chloroquine-resistant (W2) clones of P. falciparum, displaying activity in the range of 0.
View Article and Find Full Text PDFThe catalytic asymmetric synthesis of highly functionalized cyclopropanes from α-substituted allyl sulfones and silanes is reported. The reaction, using α-aryl diazoacetates or diacceptor diazo reagents, catalyzed by a chiral rhodium complex (Rh ((S)-BTPCP) ), furnished the corresponding cyclopropanes in moderate to high yields (27-97 %), high diastereoselectivities (68 : 32 to 20 : 1 d.r.
View Article and Find Full Text PDFVaccination against infectious diseases is a cornerstone of veterinary medicine in the prevention of disease transmission, illness severity, and often death in animals. In North American equine medicine, equine vaccines protecting against tetanus, rabies, Eastern and Western equine encephalomyelitis, and West Nile are core vaccines as these have been classified as having a heightened risk of mortality, infectiousness, and endemic status. Some guidelines differ from the label of vaccines, to improve the protection of patients or to decrease the unnecessary administration to reduce potential side effects.
View Article and Find Full Text PDFgem-Heteroatom-substituted fluoroalkenes have received little attention despite their great potential in medicinal chemistry or in fine chemistry. Indeed, due to the electronic and steric similarity between the fluoroalkene moiety and the amide bond as well as the high strength of the carbon-fluorine bond, these gem-heteroatom-substituted fluoroalkenes could be envisioned as stable mimics of various important organic functions, such as phosphates, carbamates, S-thiocarbamates and ureas. We present herein an overview describing the syntheses over the last decade of heteroatom-substituted fluoroalkenes in geminal position.
View Article and Find Full Text PDFThe photocatalytic contra-thermodynamic E→Z isomerization of vinyl boronates by using a binaphthol catalyst is disclosed. The reaction, based on the transient formation of a suitable chromophore with a BINOL derivative as the catalyst, allowed geometrical isomerization in good-to-excellent Z/E ratio and excellent-to-quantitative yields. The mechanism of this E→Z contra-thermodynamic isomerization was studied, and the formation of a transient chromophore species is suggested.
View Article and Find Full Text PDFDecarboxylation strategy has been emerging as a powerful tool for the synthesis of fluorine-containing organic compounds that play important roles in various fields such as pharmaceuticals, agrochemicals, and materials science. Considerable progress in decarboxylation has been made over the past decade towards the construction of diverse valuable fluorinated fine chemicals for which the fluorinated part can be brought in two ways. The first way is described as the reaction of non-fluorinated carboxylic acids (and their derivatives) with fluorinating reagents, as well as fluorine-containing building blocks.
View Article and Find Full Text PDFThe -thermodynamic isomerization of α- and β-substituted cinnamate derivatives catalyzed by the Cu(OAc)/-BINAP complex under blue light irradiation is reported. The use of an oxazolidinone template, which favored the complexation of the copper catalyst to the substrate, allowed the → isomerization of the catalytically formed chromophore under simple and robust reaction conditions in good to excellent ratios. The mechanism of this process based on the transient formation of a chromophore was also studied.
View Article and Find Full Text PDFA lockdown of people has been used as an efficient public health measure to fight against the exponential spread of the coronavirus disease (Covid-19) and allows the health system to manage the number of patients. The aim of this study (clinicaltrials.gov NCT00430818) was to evaluate the impact of both perceived stress aroused by Covid-19 and of emotions triggered by the lockdown situation on the individual experience of time.
View Article and Find Full Text PDFWe report here a simple and robust gold-catalyzed annulation reaction, giving - and -spirocycles in good to excellent yields. We have prepared a library of protected amines and tertiary alcohols that give, upon cyclization with alkynes, a representative set of heterospirocycles and illustrate reaction compatibility with diverse functional groups. A change in catalytic activity is possible by modifying the solvent, and two original tricyclic spirocycles were synthesized in a tandem reaction.
View Article and Find Full Text PDFA series of iodinated ligands for the SPECT imaging of 5-HT receptors was designed starting from the previously reported hit MR-26132. We focused on the modulation of the piperidine-containing lateral chain by introducing hydrophilic groups in order to decrease the liphophilicity of the new ligands. All the synthesized compounds were tested for their binding affinities on 5-HTRs and based on the Ligand Lipophilicity Efficiency approach, compound 13 was further selected for radioiodination with iodine-125 and imaging experiments.
View Article and Find Full Text PDFCase Summary: A 5-month-old cat was evaluated for a 3 week history of cough, nasal discharge, decreased appetite and weight loss. Musculoskeletal examination was normal and serum creatine kinase (CK) activity was within the reference interval. The cat was treated during the next 10 months for chronic, persistent pneumonia.
View Article and Find Full Text PDFObjectives: Alpha(α)2-agonist administration has been documented to increase blood glucose concentrations in many species. The aim of this study was to further describe the effect of dexmedetomidine on glucose and its regulatory hormones in healthy cats.
Methods: A randomized crossover study using eight healthy cats with a 14 day washout period was used to assess the effect of dexmedetomidine (10 μg/kg IV) and saline on glucose, cortisol, insulin, glucagon and non-esterified fatty acid (NEFA) concentrations at 0, 20, 60, 120 and 180 mins post-administration.
Efficient ligand-free palladium catalyzed Mizoroki-Heck reaction allowed the formation of trisubstituted α-trifluoromethylacrylates. The reaction showed good chemical tolerance and furnished moderate to excellent yields of reaction. Silver salt additive proved to be essential for the reaction.
View Article and Find Full Text PDFThe palladium-mediated C-H radio-iodination of arenes using sodium iodide as the primary isotopic source is reported and performed without chemical know-how in 30 min and applied to the synthesis of complex radio-iodinated compounds of biological interest.
View Article and Find Full Text PDFThe first catalytic asymmetric synthesis of highly functionalized pentafluorosulfanylated pyrrolidines is described. The method, based on a 1,3-dipolar cycloaddition reaction of aryl and heteroaryl-substituted glycine Schiff bases with pentafluorosulfanyl acrylic esters, gave access to a broad range of pyrrolidines bearing aryl, naphtyl, and heteroaryl groups. By using Xing-Phos as a catalyst, the corresponding products were obtained in good yields, good to high regioselectivity, and excellent diastereo- and enantioselectivities (up to 98 % ee).
View Article and Find Full Text PDFCyclic nucleotide phosphodiesterase type 4 (PDE4), that controls intracellular level of cyclic nucleotide cAMP, has aroused scientific attention as a suitable target for anti-inflammatory therapy in respiratory diseases. Here we describe the development of two families of pyridazinone derivatives as potential PDE4 inhibitors and their evaluation as anti-inflammatory agents. Among these derivatives, 4,5-dihydropyridazinone representatives possess promising activity, selectivity towards PDE4 isoenzymes and are able to reduce IL-8 production by human primary polymorphonuclear cells.
View Article and Find Full Text PDFJ Vet Intern Med
January 2018
Background: The clinicopathologic aspects of pyelonephritis have not been reported in companion animals.
Hypothesis/objectives: To evaluate the prevalence of pyelonephritis diagnosed in dogs in a academic referral population, describe the clinical signs and the diagnostic test results in dogs with pyelonephritis, and identify concurrent disorders in order to determine potential risk factors for pyelonephritis.
Animals: Forty-seven dogs with a histopathologic diagnosis of pyelonephritis from the teaching hospitals of three Canadian veterinary colleges.
The Pd-catalyzed diastereoselective trifluoromethylthiolation of acrylamides was developed to allow the formation of the Z-isomer as a single product. Using a C-H bond functionalization strategy, the method was applied to a broad range of α-aryl, α-alkyl, and α,β-disubstituted acrylamides bearing the amide derived from the 8-aminoquinoline as a directing group. Mechanistic studies as well as postfunctionalization of the products were performed.
View Article and Find Full Text PDFThe price volatility of fossil resources, the uncertainty of their long-term availability and the environmental, climatic and societal problems posed by their operation lead to the need of an energy transition enabling the development and utilization of other alternative and sustainable resources. Acknowledging that indirect land-use change can increase greenhouse gas emission, the European Union (EU) has reshaped its biofuel policy. It has set criteria for sustainability to ensure that the use of biofuels guarantees real carbon savings and protects biodiversity.
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