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Eugenol-ß-cyclodextrin complex has been widely used because of the enhanced stability and conservation of the properties of eugenol. Applications in food and health sciences have been shown previously, which makes this complex an excellent model to understand and develop methodologies for the analysis and prediction of physical properties. In this work, the dynamics of eugenol incorporated into ß-cyclodextrin are presented, using NMR relaxation rates, and the predictive capabilities of molecular dynamics simulations are discussed. Results show a hindered rotation of eugenol around the principal inertial axes when located inside ß-cyclodextrin. Moreover, a translational movement of the whole complex is demonstrated.
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Metabolic syndrome is a set of risk factors that consist of abdominal obesity, arterial hypertension, alterations in the lipid profile, and hyperglycemia. The current therapeutic strategy includes polypharmacy, using three or more drugs to control each syndrome component. However, this approach has drawbacks that could lead to therapeutic failure. Multitarget drugs are molecules with the ability to act on different targets simultaneously and are an attractive alternative for treating complex diseases such as metabolic syndrome. Previously, we identified a triamide derivative of 5-aminoanthranilic acid that exhibited hypoglycemic, hypolipemic, and antihypertensive activities simultaneously. In the present study, we report the synthesis and in combo evaluation of new derivatives of anthranilic acid, intending to identify the primary structural factors that improve the activity over metabolic syndrome-related parameters. We found that substitution on position 5, incorporation of 3,4-dimethoxyphenyl substituents, and having a free carboxylic acid group lead to the in vitro inhibition of HMG-CoA reductase, and simultaneously the diminution of the serum levels of glucose, triglycerides, and cholesterol in a diet-induced in vivo model.
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Encapsulation is one of the technologies applied for the formulation of biological control agents. The function of the encapsulating matrix is to protect the biological material from environmental factors, while dehydration allows for its viability to be prolonged. An advantage of dehydrated encapsulation formulations is that they can be stored for long periods. However, vegetative cells require low-stress dehydration processes to prevent their loss of viability. Herein we describe the fabrication of a dehydrated encapsulate of the Streptomyces CDBB1232 mycelium using sodium alginate with a high concentration of mannuronic acid; sodium alginate was added with YGM medium for mycelium protection purposes. The encapsulation was carried out by extrusion, and its dehydration was carried out in a rotating drum fed with air at room temperature (2-10 L min-1). The drying of the capsules under air flows higher than 4 L min-1 led to viability loss of the mycelium. The viability loss can be decreased up to 13% by covering the alginate capsules with gum arabic. Compared to conventional dehydration processes, air moisture removal can be lengthy, but it is a low-cost method with the potential to be scaled.
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Metabolic syndrome (MetS) is a complex disease that affects almost a quarter of the world's adult population. In MetS, diabetes, obesity, hyperglycemia, high cholesterol, and high blood pressure are the most common disorders. Polypharmacy is the most used strategy for managing conditions related to MetS, but it has drawbacks such as low medication adherence. Multitarget ligands have been proposed as an interesting approach to developing drugs to treat complex diseases. However, suitable preclinical models that allow their evaluation in a context closer to a clinical situation of a complex disease are needed. From molecular docking studies, compound 1b, a 5-aminoanthranilic acid derivative substituted with 4'-trifluoromethylbenzylamino and 3',4'-dimethoxybenzamide moieties, was identified as a potential multitarget drug, as it showed high in silico affinity against targets related to MetS, including PPAR-α, PPAR-γ, and HMG-CoA reductase. It was evaluated in a diet-induced MetS rat model and simultaneously lowered blood pressure, glucose, total cholesterol, and triglyceride levels after a 14-day treatment. No toxicity events were observed during an acute lethal dose evaluation test at 1500 mg/kg. Hence, the diet-induced MetS model is suitable for evaluating treatments for MetS, and compound 1b is an attractive starting point for developing multitarget drugs.
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Molecular logic gates (MLGs) are compounds that can solve Boolean logic operations to give an answer (OUTPUT) upon receiving a stimulus (INPUT). These derivatives can be used as biological sensors and are promising substitutes for the present logic gates. Although MLGs with complex molecular structures have been reported, they often show stability problems. To address this problem, we describe herein six stable pseudo-hemiindigo-derived MLGs capable of solving complex logic operations. MLGs 7, 8, 9, and 10 can solve a complex logic operation connecting 4 logic gates using 2 different wavelengths (445 nm and 400 nm) and the presence of p-TsOH and triethylamine (TEA) as inputs; MLG 11 solves a complex logic operation connecting 3 logic gates and uses 3 inputs, one wavelength of 445 nm and the presence of p-TsOH and TEA; and MLG 12 can only solve one logic operation (INH) and uses only the presence of p-TsOH and TEA as an input. Each operating method of the MLGs was evaluated with several techniques; proton interactions with MLGs were screened with NMR by titrating with p-TsOH, the photochemical properties were examined with absorption ultraviolet-visible (UV-Vis) spectroscopy, and the isomerization dynamics were examined with NMR using the two wavelengths for isomerization (photostationary isomer). The results indicate that the pseudo-hemiindigo-derived MLGs described herein can be applied as multiplexers or data selectors that are necessary for the transient flow of information for biological and computer systems. Finally, to design different MLGs and a system that can treat more information as complex logic gates (demultiplexers), two and three MLGs were mixed in different experiments. In both cases, four inputs were employed (445 nm, 400 nm, p-TsOH and TEA), yielding more outputs. Detailed information about the system dynamics was obtained from NMR experiments.
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Cartilage-forming lesions include tumours that can vary in severity from benign enchondromas to high-grade malignant chondrosarcomas. Chondrosarcoma is the second most frequent malignant bone tumour, accounting for 20-30% of all malignant bone neoplasms. Surgery is the standard treatment for cartilage tumours (CTs); however, their incidental diagnosis and the difficult differentiation of low-grade lesions like chondrosarcoma grade I from benign entities like enchondroma are challenges for clinical management. In this sense, the search for circulating biomarkers for early detection and prognosis is an ongoing interest. Targeted metabolomics is a powerful tool that can propose potential biomarkers in biological fluids as well as help to discover disturbed metabolic pathways to reveal tumour pathogenesis. In this context, the aim of this study was to investigate the 1 H nuclear magnetic resonance metabolomic serum profile of patients with CTs contrasted with healthy controls. Forty-one metabolites were identified and quantified; the multivariate statistical methods principal component analysis and partial least squares discriminant analysis reveal a clear separation of the CT group, that is, the differential metabolites that were involved in two main metabolic pathways: the taurine and hypotaurine metabolism and synthesis and degradation of ketone bodies. Our results represent preliminary work for emergent serum-based diagnostics or prognostic methods for patients with chondrogenic tumours.
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Biomarcadores Tumorais/sangue , Cartilagem/metabolismo , Condrossarcoma/diagnóstico , Espectroscopia de Ressonância Magnética/métodos , Soro/química , Adulto , Idoso , Condroma/metabolismo , Análise Discriminante , Feminino , Humanos , Masculino , Redes e Vias Metabólicas , Metabolômica/métodos , Pessoa de Meia-Idade , Simulação de Dinâmica Molecular , Análise Multivariada , Estadiamento de Neoplasias/métodos , Projetos Piloto , Soro/metabolismoRESUMO
Infection from multidrug resistant bacteria has become a growing health concern worldwide, increasing the need for developing new antibacterial agents. Among the strategies that have been studied, biofilm inhibitors have acquired relevance as a potential source of drugs that could act as a complement for current and new antibacterial therapies. Based on the structure of 2-alkyl-3-hydroxy-4-quinolone and N-acylhomoserine lactone, molecules that act as mediators of quorum sensing and biofilm formation in Pseudomonas aeruginosa, we designed, prepared, and evaluated the biofilm inhibition properties of long chain amide derivatives of 2-amino-4-quinolone in Staphylococcus aureus and P. aeruginosa. All compounds had higher biofilm inhibition activity in P. aeruginosa than in S. aureus. Particularly, compounds with an alkyl chain of 12 carbons exhibited the highest inhibition of biofilm formation. Docking scores and molecular dynamics simulations of the complexes of the tested compounds within the active sites of proteins related to quorum sensing had good correlation with the experimental results, suggesting the diminution of biofilm formation induced by these compounds could be related to the inhibition of these proteins.
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4-Quinolonas/química , Amidas/síntese química , Amidas/farmacologia , Biofilmes/efeitos dos fármacos , Simulação por Computador , Amidas/química , Domínio Catalítico , Ligantes , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Espectroscopia de Prótons por Ressonância Magnética , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Percepção de Quorum/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologiaRESUMO
In this work, microwave synthesis, chemical, optical and electrochemical characterization of three small organic molecules, TPA-TPD, TPA-PT-TPD and TPA-TT-TPD with donor-acceptor structure and their use in organic photovoltaic cells are reported. For the synthesis, 5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione was used as electron withdrawing fragment while the triphenylamine was used as electron donating fragment. Molecular electronic geometry and electronic distribution density were established by density functional theory (DFT) calculations and confirmed by optical and chemical characterization. These molecules were employed as electron-donors in the active layer for manufacturing bulk heterojunction organic solar cells, where [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) was used as electron-acceptor. As cathode, Field's metal (FM), an eutectic alloy (Bi/In/Sn: 32.5%, 51%, and 16.5%, respectively) with a melting point above 62 °C, was easily deposited by drop casting under vacuum-free process and at air atmosphere. Prepared devices based on TPA-TPD:PC71BM (1:4 w/w ratio) presented a large VOC = 0.97 V, with JSC = 7.9 mA/cm², a FF = 0.34, then, a power conversion efficiency (PCE) of 2.6%.
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Ligas/química , Fontes de Energia Elétrica , Pirróis/química , Energia Solar , Eletricidade , Transporte de Elétrons , Micro-Ondas , Modelos Moleculares , Estrutura Molecular , Luz SolarRESUMO
This paper reports the synthesis of a series of piperidones 1-8 by the Mannich reaction and analysis of their structures and conformations in solution by NMR and mass spectrometry. The six-membered rings in 2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-ones, compounds 1 and 2, adopt a chair-boat conformation, while those in 2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-ones, compounds 3-8, adopt a chair-chair conformation because of stereoelectronic effects. These stereoelectronic effects were analyzed by the (1) J C-H coupling constants, which were measured in the (13)C satellites of the (1)H NMR spectra obtained with the hetero-dqf pulse sequence. In the solid state, these stereoelectronic effects were investigated by measurement of X-ray diffraction data, the molecular geometry (torsional bond angles and bond distances), and inter- and intramolecular interactions, and by natural bond orbital analysis, which was performed using density functional theory at the ωB97XD/6311++G(d,p) level. We found that one of the main factors influencing the conformational stability of 3-8 is the interaction between the lone-pair electrons of nitrogen and the antibonding sigma orbital of C(7)-Heq (nNâσ*C-H(7)eq), a type of hyperconjugative interaction.
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The effect of recalcitrant hydrocarbons on the fatty acid profile from leaf, basal corm, and roots of Cyperus laxus plants cultivated in greenhouse phytoremediation systems of soils from aged oil spill-impacted sites containing from 16 to 340 g/Kg total hydrocarbons (THC) was assessed to investigate if this is a C18:3 species and if the hydrocarbon removal during the phytoremediation process has a relationship with the fatty acid profile of this plant. The fatty acid profile was specific to each vegetative organ and was strongly affected by the hydrocarbons level in the impacted sites. Leaf extracts of plants from uncontaminated soil produced palmitic acid (C16), octadecanoic acid (C18:0), unsaturated oleic acids (C18:1-C18:3), and unsaturated eichosanoic (C20:2-C20:3) acids with a noticeable absence of the unsaturated hexadecatrienoic acid (C16:3); this finding demonstrates, for the first time, that C. laxus is a C18:3 plant. In plants from the phytoremediation systems, the total fatty acid contents in the leaf and the corm were negatively affected by the hydrocarbons presence; however, the effect was positive in root. Interestingly, under contaminated conditions, unusual fatty acids such as odd numbered carbons (C15, C17, C21, and C23) and uncommon unsaturated chains (C20:3n6 and C20:4) were produced together with a remarkable quantity of C22:2 and C24:0 chains in the corm and the leaf. These results demonstrate that weathered hydrocarbons may drastically affect the lipidic composition of C. laxus at the fatty acid level, suggesting that this species adjusts the cover lipid composition in its vegetative organs, mainly in roots, in response to the weathered hydrocarbon presence and uptake during the phytoremediation process.
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Cyperus/metabolismo , Ácidos Graxos/metabolismo , Poluição por Petróleo , Folhas de Planta/metabolismo , Solo/química , Biodegradação AmbientalRESUMO
The effects of persistent organic pollutants (POPs) on humans and biodiversity are multiple and varied. Nowadays environmentally-friendly pesticides are strongly preferred to POPs. It is noteworthy that the crop protection role of pesticides and other techniques, i.e. biopesticides, plant extracts, prevention methods, organic methods, evaluation of plant resistance to certain pests under an integrated pest management (IPM), could improve the risks and benefits which must be assessed on a sound scientific basis. For this directive it is crucial to bring about a significant reduction in the use of chemical pesticides, not least through the promotion of sustainable alternative solutions such as organic farming and IPM. Biopesticides are derived from natural materials such as animals, plants, bacteria, and certain minerals. Most of them are biodegradable in relatively short periods of time. On this regard, substances from Calceolaria species emerge as a strong alternative to the use of POPs. The American genus Calceolaria species are regarded both as a notorious weeds and popular ornamental garden plants. Some have medicinal applications. Other taxa of Calceolaria are toxic to insects and resistant to microbial attack. These properties are probably associated with the presence of terpenes, iridoids, flavonoids, naphthoquinones and phenylpropanoids previously demonstrated to have interesting biological activities. In this article a comprehensive evaluation of the potential utilization of Calceolaria species as a source of biopesticides is made. The chemical profile of selected members of the Chilean Calceolaria integrifolia sensu lato complex represents a significant addition to previous studies. New secondary metabolites were isolated, identified and tested for their antifeedant, insect growth regulation and insecticidal activities against Spodoptera frugiperda and Drosophila melanogaster. These species serve as a model of insect pests using conventional procedures. Additionally, bactericidal and fungicidal activity were determined. Dunnione mixed with gallic acid was the most active fungistatic and fungicidal combination encountered. Several compounds as isorhamnetin, combined with ferulic and gallic acid quickly reduced cell viability, but cell viability was recovered quickly and did not differ from that of the control. The effect of these mixtures on cultures of Aspergillus niger, Fusarium moniliforme, Fusarium sporotrichum, Rhizoctonia solani, and Trichophyton mentagrophytes, was sublethal. However, when fungistatic isorhamnetin and dunnione were combined with sublethal amounts of both ferulic and gallic acid, respectively, strong fungicidal activity against theses strains was observed. Thus, dunnione combined with gallic acid completely restricted the recovery of cell viability. This apparent synergistic effect was probably due to the blockade of the recovery process from induced-stress. The same series of phenolics (iridoids, flavonoids, naphthoquinones and phenylpropanoids) were also tested against the Gram-negative bacteria Escherichia coli, Enterobacter agglomerans, and Salmonella typhi, and against the Gram-positive bacteria Bacillus subtilis, Sarcinia lutea, and Staphylococcus aureus and their effects compared with those that of kanamycin. Mixtures of isorhamnetin/dunnione/kaempferol/ferulic/gallic acid in various combinations were found to have the most potent bactericidal and fungicidal activity with MFC between 10 and 50 µg/ml. Quercetin was found to be the most potent fungistatic single compound with an MIC of 15 µg/ml. A time-kill curve study showed that quercetin was fungicidal against fungi assayed at any growth stage. This antifungal activity was slightly enhanced by combination with gallic acid. The primary antifungal action of the mixtures assayed likely comes from their ability to act as nonionic surfactants that disrupt the function of native membrane-associated proteins. Hence, the antifungal activity of isorhamnetin and other O-methyl flavonols appears to be mediated by biophysical processes. Maximum activity is obtained when the balance between hydrophilic and hydrophobic portions of the molecules of the mixtures becomes the most appropriate. Diterpenes, flavonoids, phenylpropanoids, iridoids and phenolic acids were identified by chromatographic procedures (HPLC-DAD), ESI-MS, and NMR hyphenated techniques.
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Antibacterianos/isolamento & purificação , Fungicidas Industriais/isolamento & purificação , Inseticidas/isolamento & purificação , Scrophulariaceae/química , Animais , Inibidores da Colinesterase/isolamento & purificação , Drosophila melanogaster , Sinergismo Farmacológico , Flavonoides/farmacologia , Ácido Gálico/farmacologia , Inseticidas/toxicidade , Testes de Sensibilidade Microbiana , Naftoquinonas/toxicidade , Spodoptera , Testes de ToxicidadeRESUMO
Expression systems based on plant cells, tissue, and organ cultures have been investigated as an alternative for production of human therapeutic proteins in bioreactors. In this work, hairy root cultures of Brassica oleracea var. italica (broccoli) were established in an airlift with mesh bioreactor to produce isoform 1 of the human growth hormone (hGH1) as a model therapeutic protein. The hGH1 cDNA was cloned into the pCAMBIA1105.1 binary vector to induce hairy roots in hypocotyls of broccoli plantlets via Agrobacterium rhizogenes. Most of the infected plantlets (90%) developed hairy roots when inoculated before the appearance of true leaves, and keeping the emerging roots attached to hypocotyl explants during transfer to solid Schenk and Hildebrandt medium. The incorporation of the cDNA into the hairy root genome was confirmed by PCR amplification from genomic DNA. The expression and structure of the transgenic hGH1 was assessed by ELISA, western blot, and MALDITOF-MS analysis of the purified protein extracted from the biomass of hairy roots cultivated in bioreactor for 24 days. Production of hGH1 was 5.1 ± 0.42 µg/g dry weight (DW) for flask cultures, and 7.8 ± 0.3 µg/g DW for bioreactor, with productivity of 0.68 ± 0.05 and 1.5 ± 0.06 µg/g DW*days, respectively, indicating that the production of hGH1 was not affected by the growth rate, but might be affected by the culture system. These results demonstrate that hairy root cultures of broccoli have potential as an alternative expression system for production of hGH1, and might also be useful for production of other therapeutic proteins.
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Reatores Biológicos , Brassica/genética , Hormônio do Crescimento Humano/química , Hormônio do Crescimento Humano/metabolismo , Raízes de Plantas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Brassica/metabolismo , Clonagem Molecular , Hormônio do Crescimento Humano/análise , Hormônio do Crescimento Humano/genética , Humanos , Proteínas Recombinantes/análise , Proteínas Recombinantes/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Técnicas de Cultura de Tecidos/métodosRESUMO
An NMR titration method has been used to simultaneously measure the acid dissociation constant (pKa) and the intramolecular NHO prototropic constant ΔKNHO on a set of Schiff bases. The model compounds were synthesized from benzylamine and substituted ortho-hydroxyaldehydes, appropriately substituted with electron-donating and electron-withdrawing groups to modulate the acidity of the intramolecular NHO hydrogen bond. The structure in solution was established by 1H-, 13C- and 15N-NMR spectroscopy. The physicochemical parameters of the intramolecular NHO hydrogen bond (pKa, ΔKNHO and ΔΔG°) were obtained from 1H-NMR titration data and pH measurements. The Henderson-Hasselbalch data analysis indicated that the systems are weakly acidic, and the predominant NHO equilibrium was established using Polster-Lachmann δ-diagram analysis and Perrin model data linearization.
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Ressonância Magnética Nuclear Biomolecular , Bases de Schiff/química , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular/métodos , Bases de Schiff/síntese química , SoluçõesRESUMO
Two new eunicellin-based diterpenes, seco-briarellinone (1) and briarellin S (2), and a known seco-asbestinin (3) have been isolated from the methanolic extract of the common octocoral Briareum asbestinum collected in Bocas del Toro, Caribbean of Panama. The structures and relative stereochemistry of the compounds were defined using extensive spectroscopic analysis including 1D, 2D-nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). Compounds 1 and 2 displayed anti-inflammatory properties inhibiting nitric oxide (NO) production induced by lipopolisacharide (LPS) in macrophages with an Inhibitory concentration 50% (IC50) of 4.7 µM and 20.3 µM, respectively. This is the first report of briarellin diterpenes containing a ketone group at C-12.
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Antozoários/química , Anti-Inflamatórios/farmacologia , Diterpenos/farmacologia , Animais , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/isolamento & purificação , Diterpenos/administração & dosagem , Diterpenos/isolamento & purificação , Concentração Inibidora 50 , Lipopolissacarídeos/toxicidade , Macrófagos/metabolismo , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismo , PanamáRESUMO
The title Schiff base compound, C(15)H(15)NO(2), crystallized as the iminium-phenolate zwitterion. The H atom is localized on the imine N atom, forming a strong intra-molecular hydrogen bond with the phenolate O atom, and giving rise to an S(6) ring motif. The mol-ecule has an E conformation about the C=N bond. In the crystal, mol-ecules are linked by O-Hâ¯O hydrogen bonds, forming chains propagating along [010]. There are also C-Hâ¯O inter-actions present.
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A structural and conformational analysis of 1-oxaspiro[2.5]octane and 1-oxa-2-azaspiro[2.5]octane derivatives was performed using (1) H, (13) C, and (15) N NMR spectroscopy. The relative configuration and preferred conformations were determined by analyzing the homonuclear coupling constants and chemical shifts of the protons and carbon atoms in the aliphatic rings. These parameters directly reflected the steric and electronic effects of the substituent bonded to the aliphatic six-membered ring or to C3 or N2. The parameters also were sensitive to the anisotropic positions of these atoms in the three-atom ring. The preferred orientation of the exocyclic substituents directed the oxidative attack.
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Aziridinas/análise , Aziridinas/química , Compostos de Epóxi/análise , Óxido de Etileno/química , Compostos de Espiro/análise , Aziridinas/síntese química , Isótopos de Carbono , Compostos de Epóxi/síntese química , Óxido de Etileno/síntese química , Espectroscopia de Ressonância Magnética/normas , Estrutura Molecular , Isótopos de Nitrogênio , Prótons , Padrões de Referência , Compostos de Espiro/síntese química , EstereoisomerismoRESUMO
The conformations and relative configurations of 20 amines, classified according to the following labeling scheme, were analyzed. Series a comprised compounds derived from N-(1-phenylethyl)cyclohexanamine, b comprised derivatives of N-[1-(naphthalen-2-yl)ethyl]cyclohexanamine, c comprised derivatives of N-(diphenylmethyl)cyclohexanamine, and d comprised derivatives of N-(propan-2-yl)cyclohexanamine. The compounds were labeled as follows: 1 indicates cyclohexanamine, 2 indicates 2-methylcyclohexanamines, 3 indicates 3-methylcyclohexanamines, 4 indicates 4-methylcyclohexanamines, and 5 indicates 4-tert-butylcyclohexanamines. These compounds were prepared without the use of stereoselective induction and, therefore, all expected stereoisomers were observed. Structural assignments were established by (1)H, (13)C, and (15)N NMR.
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Aminas/química , Ciclização , Cicloexanos/química , Espectroscopia de Ressonância Magnética/métodos , Conformação Molecular , Estrutura MolecularRESUMO
The relative acidities of the cis and trans isomers of a series of 1,5-oxazaspiro[5.5]undecane derivatives were determined by measuring DeltapK in acid-base titrations followed by (1)H NMR. Relative structural stabilities were determined by measuring substituent chemical shift and gamma-gauche effects in (13)C, (15)N, and (17)O NMR. Crystallographic characterization of a model spiro[5.5]undecane is presented to support the basicity in solid state.
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The thermodynamic products (epsilon-lactams) of the degradation of ten different spirocyclic oxaziridines were analyzed by 1H and 13C NMR spectroscopy. The preferred conformations were determined by examining the homonuclear spin-spin coupling constant and the chemical shift effects of the N-substituent and the alkyl group of the aliphatic ring on 1H and 13C NMR spectra.
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Lactamas/química , Isótopos de Carbono , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Prótons , Padrões de Referência , EstereoisomerismoRESUMO
The (1)H, (13)C, and (15)N NMR spectra of 5 exocyclic alkenes and 15 different ketimines obtained from cyclohexanone and derivatives using benzyl bromide and primary amines-are analyzed. Relative stereochemical and preferential conformations are determined by analyzing both the homonuclear coupling and the chemical shifts of the protons and carbon atoms in the aliphatic rings, which are directly related to the geometry of the double bond and the steric and electronic effects of the exocyclic group. In addition, the racemic mixture of the N-(4-methylcyclohexylidene)pyridine-3-amine derivative is resolved.