Ethyl 7-Acetyl-8a-methyl-3-(1-phenyl-1H-tetrazol-5-yl)-1,4,4a,5,6,8a-hexahydro-7H-pyrano[2,3-c]pyridazine-1-carboxylate

The Diels–Alder reaction of ethyl 3-(1-phenyl-1H-tetrazol-5-yl-1,2-diaza-1,3-butadiene-1-carboxylate with 2-acetyl-6-methyl-2,3-dihydro-4H-pyran (methyl vinyl ketone dimer) regioselectively afforded the corresponding 3-(tetrazol-5-yl)-hexahydro-7H-pyrano[2,3-c]pyridazine in quantitative yield. An X-ray crystal structure of this cycloadduct is reported.info:eu-repo/semantics/publishedVersio

Novel insights into biomass delignification with acidic deep eutectic solvents: a mechanistic study of β-O-4 ether bond cleavage and the role of the halide counterion in the catalytic performance

The development of innovative technologies for an efficient, yet eco-friendly, biomass delignification is required to achieve higher sustainability than traditional processes. In this context, the use of deep eutectic solvents (DES) for the delignification process could fulfil these requirements and stands today as a promising alternative. This work focus on understanding the fundamental chemistry behind the cleavage of B-O-4 ether bond present in 2-phenoxy-1-phenylethanol (PPE), a lignin model compound, with three acidic DES, including Propionic acid/Urea (PA:U), Lactic acid/Choline Chloride (LA:ChCl) and p-Toluenesulphonic acid/Choline chloride (pTSA:ChCl). The acidic nature of each DES influenced the efficiency of PPE cleavage and determined the extent of further side reactions of cleavage products. Although PA:U (2:1) demonstrated ability to dissolve lignin, it is unable to cleave B-O-4 ether linkage in PPE. On the other hand, LA:ChCl (10:1) allowed PPE cleavage, but an esterification between the PPE and lactic acid as well as oligomerization of lactic acid were detected. Among examined solvents, pTSA:ChCl (1:1) demonstrated the highest performance on the PPE cleavage, although the high acidity of this system lead to condensation of cleavage products at prolonged time. The presence of water decreases the ability of DES for the cleavage, but the extension of undesired side reactions was also reduced. Finally, the analysis of intermediates and products of the reactions allowed the identification of a chlorinated species of PPE that precedes the cleavage reaction. A kinetic study using pTSA:ChCl (1:1) and pTSA:ChBr (1:1) was performed to unveil the role of the halide counterion present in DES on the cleavage of <2=2 ether bond and a new reaction mechanism was herein proposed and supported by density functional theory (DFT) calculations.Altri ñ Celbi, Buckman, Crown Van Gelder, CTP, DS Smith Paper, ESKA, Essity, Holmen, ISPT, Mayr-Melnhof Eerbeek, Mets‰ Fibre, Mid Sweden University, Mondi, Omya, The Navigator Company, Sappi, Essity, Smurfit Kappa, Stora Enso, Eindhoven University of Technology, University of Aveiro, University of Twente, UPM, Valmet Technologies Oy, Voith Paper, VTT Technical Research Centre of Finland Ltd, WEPA and Zellstoff Pols.in publicatio

Gestational protein restriction induces CA3 dendritic atrophy in dorsal hippocampal neurons but does not alter learning and memory performance in adult offspring

Studies have demonstrated that nutrient deficiency during pregnancy or in early postnatal life results in structural abnormalities in the offspring hippocampus and in cognitive impairment. In an attempt to analyze whether gestational protein restriction might induce learning and memory impairments associated with structural changes in the hippocampus, we carried out a detailed morphometric analysis of the hippocampus of male adult rats together with the behavioral characterization of these animals in the Morris water maze (MWM). Our results demonstrate that gestational protein restriction leads to a decrease in total basal dendritic length and in the number of intersections of CA3 pyramidal neurons whereas the cytoarchitecture of CA1 and dentate gyrus remained unchanged. Despite presenting significant structural rearrangements, we did not observe impairments in the MWM test. Considering the clear dissociation between the behavioral profile and the hippocampus neuronal changes, the functional significance of dendritic remodeling in fetal processing remains undisclosed

Electrospun nanosized cellulose fibers using ionic liquids at room temperature

Aiming at replacing the noxious solvents commonly employed, ionic-liquid-based solvents have been recently explored as novel non-volatile and non-flammable media for the electrospinning of polymers. In this work, nanosized and biodegradable cellulose fibers were obtained by electrospinning at room temperature using a pure ionic liquid or a binary mixture of two selected ionic liquids. The electrospinning of 8 wt% cellulose in 1-ethyl-3-methylimidazolium acetate medium (a low viscosity and room temperature ionic liquid capable of efficiently dissolving cellulose) showed to produce electrospun fibers with average diameters within (470 ± 110) nm. With the goal of tailoring the surface tension of the spinning dope, a surface active ionic liquid was further added in a 0.10 : 0.90 mole fraction ratio. Electrospun cellulose fibers from the binary mixture composed of 1-ethyl-3-methylimidazolium acetate and 1-decyl-3-methylimidazolium chloride ionic liquids presented average diameters within (120 ± 55) nm. Scanning electron microscopy, X-ray diffraction analysis, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric assays were used as core methods to evaluate the structural integrity, morphology and crystallinity of the raw, electrospun, and regenerated samples of cellulose. Moreover, the photoluminescence spectra of both raw and electrospun fibers were acquired, and compared, indicating that the cellulose emitting centers are not affected by the dissolution of cellulose in ionic liquids. Finally, the use of non-volatile solvents in electrospinning coupled to a water coagulation bath allows the recovery of the ionic fluid, and represents a step forward into the search of environmentally friendly alternatives to the conventional approaches

Compatibility studies of Olanzapine pre-formulated with excipients by thermal analysis: preliminary study

Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to investigate drug-excipient interactions and, in consequence, their compatibility. For this purpose, binary mixtures of olanzapine drug substance and the excipients croscarmellose sodium, magnesium stearate and microcrystalline cellulose, were prepared and analysed. By the analysis of the binary mixtures DSC and TG curves it were observed changes on the temperature and enthalpy values of the drug melting and decomposition peak, with the likely formation of intermediate substances.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Modelling of micro-sources for security studies

International audienceThe interconnection of small, modular generation and storage technologies at the MV and LV distribution level have the potential to significantly impact power system performance. In this paper models of the main micro-generation sources are described. In particular, the models of Microturbines, Fuel Cells, Photovoltaic Systems and Wind Turbines, are described. In addition basic models of their power electronic interfaces are given. The integration of the above models in a steady state and dynamic simulation tool, which is developed in the framework of the EU funded MICROGRIDS project, will provide a simulation test platform, which will be necessary to define and evaluate the developed operational and control strategies

Fixed and volatile constituents oF genus Croton plants: C. adenoCalyx Baill -euphorBiaceae

aBstract This work describes the phytochemical analysis of Croton adenocalyx Baill (Euphorbiaceae), a plant that is representative of the species from Ceará State (Brazil). The GC-MS analysis of the essential oil, obtained by hydrodistillation of the leaves from C. adenocalyx, allowed the identification of eleven volatile constituents; the main components were identified as α-pinene (32.63%); bicyclogermacrene (13.96%); trans-caryophyllene (10.23%); germacrene D (10.14%); β-pinene (10.11%) and β-elemene (8.31%). The chromatographic purification of the ethanolic extract from the trunk bark, allowed the isolation and identification of the 6-methoxy-7-hydroxycoumarin (1) and 3´,5-dihydroxy-3,4´,7-trimethoxyflavone (2). Keywords: Euphorbiaceae, Croton adenocalyx, Essential oil, GC-MS, Flavonoid, Coumarin. resumen Este trabajo describe el análisis fitoquímico de Croton adenocalyx Baill (Euphorbiaceae), una planta representativa de las especies del Estado de Ceará-Brasil. El análisis por CG-EM del aceite esencial, obtenido por hidrodestilación de las hojas de C. adenocalyx Baill, permitió la identificación de diez constituyentes volátiles. Los componentes mayoritarios fueron identificados como α-pineno (32.63%), biciclogermacreno (13.96%), trans-cariofileno (10.23%), germacreno D (10.14%), β-pineno (10.11%) y β-elemeno (8.31%). La purificación cromatográfica del extracto etanólico de la corteza del tronco, permitió aislar e identificar la coumarina 6-metoxi-7-hidroxicumarina (1) y el 3´,5-dihidroxi-3,4´,7-trimetoxiflavona (2)

Tetra­pyridinium μ-oxido-di-μ-sulfato-bis­[chloridodioxidomolybdate(VI)]

The title salt, (C5H6N)4[Mo2Cl2O5(SO4)2], comprises four pyridinium cations for each [(MoClO2)2(μ-O)(μ-SO4)2]4− anionic unit. The asymmetric unit consists of three aggregates of the empirical formula. The tetra­anionic bimetallic molybdenum(VI) cluster is unprecedented and contains two sulfate and one oxide bridges. This structure constitutes the first example of a non-polymeric compound with terminal oxide, sulfate and halide ligands bonded to the same metal. The hydrogen bonds connecting the pyridinium cations to the molybdenum clusters are diverse, varying from strong and directional interactions to bifurcated bonds with a subsequent loss of directionality

Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period

From June 2004 to December 2007, samples were weekly collected at a fixed station located at the mouth of Ria de Aveiro (West Iberian Margin). We examined the seasonal and inter-annual fluctuations in composition and community structure of the phytoplankton in relation to the main environmental drivers and assessed the influence of the oceano-graphic regime, namely changes in frequency and intensity of upwelling events, over the dynamics of the phytoplankton assemblage. The samples were consistently handled and a final subset of 136 OTUs (taxa with relative abundance > 0.01%) was subsequently submitted to various multivariate analyses. The phytoplankton assemblage showed significant changes at all temporal scales but with an overriding importance of seasonality over longer-(inter-annual) or shorter-term fluctuations (upwelling-related). Sea-surface temperature, salinity and maximum upwelling index were retrieved as the main driver of seasonal change. Seasonal signal was most evident in the fluctuations of chlorophyll a concentration and in the high turnover from the winter to spring phytoplankton assemblage. The seasonal cycle of production and succession was disturbed by upwelling events known to disrupt thermal stratification and induce changes in the phytoplankton assemblage. Our results indicate that both the frequency and intensity of physical forcing were important drivers of such variability, but the outcome in terms of species composition was highly dependent on the available local pool of species and the timing of those events in relation to the seasonal cycle. We conclude that duration, frequency and intensity of upwelling events, which vary seasonally and inter-annually, are paramount for maintaining long-term phytoplankton diversity likely by allowing unstable coexistence and incorporating species turnover at different scales. Our results contribute to the understanding of the complex mechanisms of coastal phytoplankton dynamics in relation to changing physical forcing which is fundamental to improve predictability of future prospects under climate change.Portuguese Foundation for Science and Technology (FCT, Portugal) [SFRH/BPD/ 94562/2013]; FEDER funds; national funds; CESAM [UID/AMB/50017]; FCT/MEC through national funds; FEDERinfo:eu-repo/semantics/publishedVersio