Publications by authors named "Carlos Marcos"

A highly efficient enol-Ugi reaction of β,β-diketoamides has been developed using a novel non-heterocyclic amide-stabilised enol. This approach enables a broad reaction scope, affording β-enaminoamide peptidomimetics with constrained conformations due to CH-π interaction and C(sp)H⋯O hydrogen bonding. Notably, the use of a five-membered cyclic enol is crucial for achieving stable products in excellent yields.

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Stefano Marcaccini was one of the pioneers in the use of isocyanide-based multicomponent reactions in organic synthesis. Throughout his career at the University of Florence he explored many different faces of isocyanide chemistry, especially those geared towards the synthesis of biologically relevant heterocycles. His work inspired many researchers who contributed to other important developments in the field of multicomponent reactions and created a school of synthetic chemists that continues today.

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Since the first reports of the reaction of imines and cyclic anhydrides by Castagnoli and Cushman, this procedure has been applied to the synthesis of a variety of lactams, some of them with important synthetic or biological interest. The scope of the reaction has been extended to the use of various Schiff bases and anhydrides as well as to different types of precursors for these reagents. In recent years, important advances have been made in understanding the mechanism of the reaction, which has historically been quite controversial.

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The effects of including wine lees (WL), exhausted olive cake (EOC) and a 1:1 mixture of EOC and tomato pomace (EOCTP) in diets for fattening ruminants on in vitro fermentation parameters and CH4 production were analysed. Ten diets were studied, containing either none of the tested by-products (control), or 6.0, 12.

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The oxidative C(sp)-H intramolecular imination of hydroxycoumarin enol-Ugi adduct derivatives affords selectively diversely substituted imidazolocoumarins in one pot. The amide group derived from the enol-Ugi isocyanide component directs the functionalisation of the adjacent C(sp)-H and then is lost as an isocyanate molecule in an unprecedented transformation. This strategy was applied for the synthesis of potential modulators of innate immune system receptor TLR7, which showed high binding affinities in the molecular docking studies.

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The extraordinary organoleptic qualities of Iberian ham derive from the singular producing pig breed and from the traditional rearing conditions, both of which define its lipid content and composition. In this work H NMR spectroscopy is used for the first time to analyse the lipid profile of Iberian hams as determinant of quality. Quantification of fatty acids is readily obtained from the spectra, with the monounsaturated fatty acids standing out, especially in the higher quality hams.

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Keto piperazines and aminocoumarins are privileged building blocks for the construction of geometrically constrained peptides and therefore valuable structures in drug discovery. Combining these two heterocycles provides unique rigid polycyclic peptidomimetics with drug-like properties including many points of diversity that could be modulated to interact with different biological receptors. This work describes an efficient multicomponent approach to condensed chromenopiperazines based on the novel enol-Ugi reaction.

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This study was conducted to investigate the nutritive value of avocado and mango fruit wastes, and to assess the possibility of preserving the wastes into multi-nutrient blocks (MB). Both peels and a pulp:peels (PP) mixture of each fruit were analyzed for chemical composition and in vitro fermentation with goats' ruminal fluid. Wastes had low-dry matter (DM) content (<250 g/kg), with those from mango having high non-structural carbohydrates content (>800 g/kg DM) and those from avocado high fat levels (>580 g/kg DM).

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The potential of broccoli wastes (florets and stems) as ruminant feed was analyzed using in vitro and in situ techniques. Both stems and florets had high moisture content (90.6 and 86.

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The study analyzed the characteristics, chemical composition, and gas production kinetics of and silages. Each seaweed was ensiled in vacuum bags (three bags/silage) following a 2 × 3 factorial design, with two pre-treatments (unwilted or pre-wilted) and three silage types: unwashed seaweed ensiled without additive; seaweed washed and ensiled without additive; and seaweed washed and ensiled with 4 g of formic acid (FAC) per kg seaweed. Silages were kept for 3 months in darkness at 20 °C.

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In order to describe manifestations from patients with coronavirus disease 2019 (COVID-19), sociodemographic variables such as, previous medical history, clinical and radiological manifestations, treatments and evolution of patients were evaluated. This took place from March 6th to 25th, 2020, in the "Edgardo Rebagliati Martins" National Hospital in Lima. Seventeen patients were registered: 76% were male, with an average age of 53.

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The objective of this study was to analyze the chemical composition, in vitro ruminal fermentation, and intestinal digestibility of discarded samples of four Brassica vegetables: Brussels sprouts (BS), white cabbage, Savoy cabbage, and red cabbage, and to assess the effects of including increasing amounts of BS in the concentrate of a dairy sheep diet on in vitro fermentation, CH production, and in situ degradation of the diets. All cabbages had low dry matter content (DM; <16.5%), but their DM had high crude protein (19.

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Olive oil extraction generates olive cake (OC) that could be used in ruminant feeding. However, the chemical composition of OC is affected by multiple factors, being therefore highly variable. The objective of this study was to analyse the influence of storage time and further processing: crude, exhausted (subjected to a second oil extraction) and cyclone (obtained from a cyclone separator) on nutritive value of OC samples.

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The objective of this study was to determine the variability in nutritive value for ruminants of tomato pomace (TP) samples and analyze its effect on in vitro fermentation when it was included in a high-concentrate diet. Twelve TP samples were obtained from two processing plants at weekly intervals and analyzed for chemical composition, in vitro rumen fermentation, and intestinal digestibility. The chemical composition of TP did not differ between processing plants and only slight variations were observed among sampling times.

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We report an easy multicomponent synthesis of polycyclic isoindoles from cyclic 1,3-dicarbonyls, aldehydes, isocyanides, and maleimides. The key step consists of the one-pot Diels-Alder trapping of a reactive 2-aminofuran intermediate, formed by a sequence of a Knoevenagel condensation and a [4+1] cycloaddition. Moreover, a further microwave-promoted dehydrogenative N-C bond forming reaction allows the straightforward synthesis of a natural product like isoindolocarbazole, validating the utility of our methodology to obtain isoindoles as useful intermediates for the synthesis of complex polycyclic molecules.

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The objective of this study was to determine the variability in the chemical composition and in vitro ruminal fermentation of olive cake (OC) by-products. Forty-two OC samples with different storage times (1⁻14 months) and processing (25 crude (COC), 9 exhausted (EOC) and 9 cyclone (CYOC)) were fermented in vitro with sheep ruminal fluid. Exhausted OC samples had a lower ether extract content than COC and CYOC (15.

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Article Synopsis
  • Aminoxanthones are a group of therapeutically relevant compounds that have been difficult to synthesize until now.
  • A new, simple one-step reaction involving isocyanides and carbonylchromones enables the production of aminodihydroxanthones and fully aromatized aminoxanthones.
  • The reaction's mechanism is complex, with critical steps requiring a water molecule for tautomerization, which is the slowest part of the process, even though earlier steps are more energy-efficient.
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Objectives: The MobiGuide project aimed to establish a ubiquitous, user-friendly, patient-centered mobile decision-support system for patients and for their care providers, based on the continuous application of clinical guidelines and on semantically integrated electronic health records. Patients would be empowered by the system, which would enable them to lead their normal daily lives in their regular environment, while feeling safe, because their health state would be continuously monitored using mobile sensors and self-reporting of symptoms. When conditions occur that require medical attention, patients would be notified as to what they need to do, based on evidence-based guidelines, while their medical team would be informed appropriately, in parallel.

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A highly convergent and operationally simple approach to mycotoxin-related 4-amino-substituted 1-hydroxydihydroxanthones is described. The target compounds are obtained in one pot by the multicomponent reaction of 3-carbonylchromones, isocyanides, and nonsymmetric dienophiles. The reaction, which involves a tandem [4 + 1]-[4 + 2] cycloaddition, efficiently affords a variety of both monomeric and dimeric polysubstituted dihydroxanthones structurally similar to bioactive ergochromes.

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Objective: We show how the HL7 Virtual Medical Record (vMR) standard can be used to design and implement a data integrator (DI) component that collects patient information from heterogeneous sources and stores it into a personal health record, from which it can then retrieve data. Our working hypothesis is that the HL7 vMR standard in its release 1 version can properly capture the semantics needed to drive evidence-based clinical decision support systems.

Materials And Methods: To achieve seamless communication between the personal health record and heterogeneous data consumers, we used a three-pronged approach.

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The first multicomponent coupling of isocyanides, α,β-unsaturated carbonylic compounds and dienophiles, based on the trapping of unstable intermediate 2-aminofurans, is described. This novel tandem [4 + 1]-[4 + 2] cycloaddition is efficiently catalysed by yttrium triflate and constitutes an operationally simple and highly convergent approach to a variety of polysubstituted anilines. Moreover, this methodology permits the use of tert-butylisocyanide as a convertible isocyanide to yield directly N-unprotected anilines in the same pot.

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Heterocyclic enols are used for the first time as acid components in an Ugi-type multicomponent condensation. For that purpose, we have chosen enols containing a Michael acceptor, in order to facilitate an irreversible rearrangement of the primary Ugi adduct. The new four-component process leads readily and efficiently to heterocyclic enamines containing at least six elements of diversity.

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In this work, tunable series and parallel resonators based on a nematic liquid crystal cell as variable capacitance are proposed and characterized. Tunable resonance frequencies in the range of kHz have been obtained for the combination of the inductance and the liquid crystal cell (capacitance) used in the proposed circuits. Tuning range in frequency obtained is around an octave.

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A new temperature-frequency converter based on the variation of the dielectric permittivity of the Liquid Crystal (LC) material with temperature has been demonstrated. Unlike other temperature sensors based on liquid crystal processing optical signals for determining the temperature, this work presents a system that is able to sense temperature by using only electrical signals. The variation of the dielectric permittivity with temperature is used to modify the capacitance of a plain capacitor using a LC material as non-ideal dielectric.

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We report a novel Lewis acid catalysed tandem reaction of isocyanides, chromone 3-carboxylic acid and nucleophiles. An experimentally very simple procedure, involving the use of microwave irradiation in the presence of a Lewis acid catalyst, affords a representative collection of chromone-2-carboxamides and chromone-2-carboxamido-3-esters in high yields, in just a few minutes. Such an unprecedented strategy is formally equivalent to a conjugate addition of isocyanides to Michael acceptors.

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