Search results for "Bene"
showing 10 items of 2408 documents
Entre caritas et commons. De l’historicité du bien commun
2014
Abstract 1390: A combination of natural polyphenols, a NAD+ booster, and a Toll-like receptor 2/6 agonist exerts high radioprotection in normal tissu…
2021
Abstract Ionizing radiation damages cells via direct ionization of DNA and other cellular targets as well as by indirect effects through reactive oxygen species. The response to radiation exposure depends on the cell type and dose of radiation, inherent tissue sensitivity and repair, and modulating intracellular factors that include cell cycle status, O2 pressure, and levels of thiols and other antioxidants. Potentially protective agents against exposure to harmful radiation have been investigated for decades. However, no ideal radioprotector is currently available. A wide range of phytochemicals are antioxidants and, thus, potentially radioprotective. Topical administration of Pterostilben…
Asymmetric Synthesis of Spirobenzazepinones with Atroposelectivity and Spiro-1,2-Diazepinones by NHC-Catalyzed [3+4] Annulation Reactions
2016
A strategy for the NHC-catalyzed asymmetric synthesis of spirobenzazepinones, spiro-1,2-diazepinones, and spiro-1,2-oxazepinones has been developed via [3+4]-cycloaddition reactions of isatin-derived enals (3C component) with in-situ-generated aza-o-quinone methides, azoalkenes, and nitrosoalkenes (4atom components). The [3+4] annulation strategy leads to the seven-membered target spiro heterocycles bearing an oxindole moiety in high yields and excellent enantioselectivities with a wide variety of substrates. Notably, the benzazepinone synthesis is atroposelective and an all-carbon spiro stereocenter is generated.
Beneficial effects of a methanolic extract of Globularia alypum on glycaemia, lipid peroxidation and antioxidant enzymes activities in rats with stre…
2008
Abstract 1605: Pterostilbene, a natural phytoalexin, effectively protects against UVB-induced skin carcinogenesis by increasing antioxidant cellular …
2014
Abstract Clinical and laboratory studies have demonstrated that skin exposure to ultraviolet radiation (UV) is the main cause of non-melanoma skin cancer (NMSC) (≈ 99%) and melanoma (≈ 95%) development. The procarcinogenic effects of solar exposure are mainly due to UVB radiation (290-320 nm range), the same tight range that produces burning in human skin (erythema), inflammation, oxidative stress, DNA damage, etc. The number of skin cancers around the world keeps increasing and, thus, it is an urgent need to find effective protection remedies. Phytoalexins of polyphenolic structure are naturally occurring compounds involved in the defense against pathogens and environmental stresses in pla…
Potato pulp as a composting substrate
2014
Potato pulp is a waste, which is produced in considerable quantities by starch manufacturing industry. Addition of pulp fibre residue to soil results in beneficial effects on soil physical and biochemical properties. In this study, organic potato pulp was mixed with organic grass in three concentrations (75:25 (A), 50:50 (B) and 25:75 (C) % w/w) with the aim of comparing the dynamics of the composting process during a 30-day period. A mini-field experiment was conducted in 0.7 m 3 windrows which were left without covering and additional mixing during composting process, except sampling procedure. During 30-days’ experiment the C:N ratio decreased from 25÷30 to 13÷17 indicating the active co…
Understanding the high reactivity of carbonyl compounds towards nucleophilic carbenoid intermediates generated from carbene isocyanides
2015
The high reactivity of carbonyl compounds towards the carbenoid intermediate cis-IN, generated in situ by the addition of methyl isocyanide to dimethyl acetylenedicarboxylate (DMAD), has been investigated at the MPWB1K/6-311G(d,p) computational level by using Molecular Electron-Density Theory (MEDT). This multicomponent (MC) reaction is a domino process that comprises two sequential reactions: (i) the formation of a nucleophilic carbenoid intermediate trans-IN; and (ii) the nucleophilic attack of cis-IN on the carbonyl compound, resulting in the formation of the final 2-iminofuran derivative. The present MEDT study establishes that the high nucleophilic character and the electronic structur…
Organocatalytic synthesis of new telechelic polycarbonates and study of their chemical reactivity
2015
Abstract A two-step versatile process for telechelic polycarbonates synthesis is described. 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) was used as thermolabile precursor of N-heterocyclic carbene (NHC) organocatalyst. In a first step, synthesized branched fatty diols or commercially available linear diols were reacted with an excess of dimethylcarbonate (DMC) to afford oligocarbonates with methylcarbonate end-groups. Then, the methylcarbonate groups were reacted with hydroxyl groups of 9-decen-1-ol, 4-hexyn-1-ol and 4-hydroxybenzene ethanol leading to telechelic oligomers with alkene, alkyne and phenol functionalities. Reactivity of these end-groups towards polymerization was …
An N-heterocyclic carbene/iridium hydride complex from the oxidative addition of a ferrocenyl-bisimidazolium salt: implications for synthesis.
2004
Understanding the mechanism of the N-heterocyclic carbene-catalyzed ring-expansion of 4-formyl-β-lactams to succinimide derivatives
2009
The mechanism of the N-heterocyclic carbene (NHC)-catalyzed ring-expansion of 4-formyl-β-lactams to succinimides has been studied using DFT methods at the B3LYP/6-31G∗∗ level. The first step is the nucleophilic attack of NHC to the aldehyde to yield the zwitterionic intermediate, which by a proton-transfer process affords the Breslow intermediate. The lactam N–C breaking bond in this intermediate yields an enol-amidate, which by a keto–enol type equilibrium becomes the ketone form. The subsequent ring-closure achieved by the nucleophilic attack of the amidate to carbonyl carbon allows the formation of the five-membered ring. Finally, elimination of NHC affords the succinimide. Analysis of t…