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1.
Biomolecules ; 14(5)2024 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-38785935

RESUMO

Although both localized nuclear magnetic resonance spectroscopy (MRS) and non-localized nuclear magnetic resonance spectroscopy (NMR) generate the same information, i.e., spectra generated by various groups from the structure of metabolites, they are rarely employed in the same study or by the same research group. As our review reveals, these techniques have never been applied in the same study of methylmalonic acidemia (MMA), propionic acidemia (PA) or vitamin B12 deficiency patients. On the other hand, MRS and NMR provide complementary information which is very valuable in the assessment of the severity of disease and efficiency of its treatment. Thus, MRS provides intracellular metabolic information from localized regions of the brain, while NMR provides extracellular metabolic information from biological fluids like urine, blood or cerebrospinal fluid. This paper presents an up-to-date review of the NMR and MRS studies reported to date for methylmalonic and propionic acidemias. Vitamin B12 deficiency, although in most of its cases not inherited, shares similarities in its metabolic effects with MMA and it is also covered in this review.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos , Espectroscopia de Ressonância Magnética , Acidemia Propiônica , Humanos , Acidemia Propiônica/diagnóstico , Acidemia Propiônica/metabolismo , Erros Inatos do Metabolismo dos Aminoácidos/diagnóstico , Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Deficiência de Vitamina B 12/diagnóstico , Deficiência de Vitamina B 12/metabolismo , Ácido Metilmalônico/metabolismo
2.
Materials (Basel) ; 16(20)2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37895689

RESUMO

Solid activators based on waste glass for the manufacture of one-part alkali-activated fly ash/red mud materials were synthesized, characterized, and tested in this work. The synthesis was carried out via alkaline fusion with sodium hydroxide at different reaction temperatures and at different sodium hydroxide/waste glass mass ratios. The results showed that the reaction temperature decisively influences the properties of the obtained solid activators. Thus, the best results regarding the water solubility of solid activators were obtained for the synthesis temperature of 600 °C, regardless of the sodium hydroxide/waste glass mass ratio. Also, the use of these assortments of solid activators led to obtaining the best compressive strength of one-part alkali-activated fly ash/red mud materials. The best results were obtained for the solid activator synthesized at a temperature of 600 °C and a sodium hydroxide/glass waste mass ratio of two.

3.
Pharmaceutics ; 15(4)2023 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-37111552

RESUMO

The poor water solubility of natural antioxidants restricts their bioavailability and therapeutic use. We aimed to develop a new phytosome formulation with active compounds from extracts of ginger (GINex) and rosehips (ROSAex) designed to increase their bioavailability, antioxidant and anti-inflammatory properties. The phytosomes (PHYTOGINROSA-PGR) were prepared from freeze-dried GINex, ROSAex and phosphatidylcholine (PC) in different mass ratios using the thin-layer hydration method. PGR was characterized for structure, size, zeta potential, and encapsulation efficiency. Results showed that PGR comprises several different populations of particles, their size increasing with ROSAex concentration, having a zeta potential of ~-21mV. The encapsulation efficiency of 6-gingerol and ß-carotene was >80%. 31P NMR spectra showed that the shielding effect of the phosphorus atom in PC is proportional to the amount of ROSAex in PGR. PGR with a mass ratio GINex:ROSAex:PC-0.5:0.5:1 had the most effective antioxidant and anti-inflammatory effects in cultured human enterocytes. PGR-0.5:0.5:1 bioavailability and biodistribution were assessed in C57Bl/6J mice, and their antioxidant and anti-inflammatory effects were evaluated after administration by gavage to C57Bl/6J mice prior to LPS-induced systemic inflammation. Compared to extracts, PGR induced a 2.6-fold increase in 6-gingerol levels in plasma and over 40% in the liver and kidneys, in parallel with a 65% decrease in the stomach. PGR treatment of mice with systemic inflammation increased the sera antioxidant enzymes paraoxonase-1 and superoxide dismutase-2 and decreased the proinflammatory TNFα and IL-1ß levels in the liver and small intestine. No toxicity was induced by PGR either in vitro or in vivo. In conclusion, the phytosome formulation of GINex and ROSAex we developed resulted in stable complexes for oral administration with increased bioavailability, antioxidant and anti-inflammatory potential of their active compounds.

4.
Int J Biol Macromol ; 230: 123162, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36623620

RESUMO

Due to its inherent properties and wide availability, cellulose acetate is an extremely competitive candidate for the production of polymeric membranes. However, for best results in particular applications, membrane modification is required in order to minimize unwanted interactions and introduce novel characteristics to the pristine polymer. In this study, the surface of commercial cellulose acetate membranes was functionalized with 4'-aminobenzo-15-crown-5 ether, using a covalent bonding approach. The main goal was the improvement of the membranes biomineralization ability, thus making them prospective materials for bone regeneration applications. The proposed reaction mechanism was confirmed by XPS and NMR analysis while the presence of the functionalization agents in the membranes structure was showed by ATR FT-IR and Raman spectra. The effects of the functionalization process on the morphology, thermal and mechanical properties of the membranes were studied by SEM, TGA and tensile tests. The obtained results revealed that the cellulose acetate membranes were successfully functionalized with crown ether and provided a good understanding of the interactions that took place between the polymer and the functionalization agents. Moreover, promising results were obtained during the Taguchi biomineralization studies. SEM images, EDX mapping and XRD spectra indicating that the CA-AB15C5 membranes have a superior Ca2+ ions retention ability, this causing an accentuated calcium phosphate deposition on the modified polymeric fibers, compared to the neat CA membrane.


Assuntos
Éteres de Coroa , Osseointegração , Espectroscopia de Infravermelho com Transformada de Fourier , Polímeros/química , Membranas Artificiais
5.
Diagnostics (Basel) ; 12(7)2022 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-35885579

RESUMO

Most patients presenting in an emergency unit with acute coronary syndromes (ACS) (which include non-ST-elevation myocardial infarction (NSTEMI), ST-elevation MI (STEMI), and unstable angina) usually meet at least two cardiovascular risk factors, such as dyslipidemia, arterial hypertension, diabetes mellitus type 2, obesity, history of or current smoking, etc. Most ACS patients suffer from a type of dyslipidemia, and in addition to this there are ACS patients rushed into the emergency units for which the feeding status is unknown. Thus, we set out to evaluate the effect of fasting on 16 blood metabolite concentrations and 114 lipoprotein parameters on one control group and a group of statin-treated ACS patients hospitalized in a cardiovascular emergency unit, using Nuclear Magnetic Resonance (NMR) spectroscopy. The results indicated trends (in terms of number of cases, but not necessarily in terms of the magnitude of the effect) for as many as four metabolites and 48 lipoproteins. The effect was defined as a trend for results showing over 70% of the cases from either one or both groups that experienced parameter changes in the same direction (i.e., either increased or decreased). In terms of magnitude, the effect is rather low, leading to the overall conclusion that in cardiovascular (CV) emergency units, the blood samples analyzed in any feeding status would provide close results and very valuable information regarding prognosis and for fast decisions on patient's proper management.

6.
Environ Pollut ; 308: 119664, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35738521

RESUMO

Exposure to per- and polyfluoroalkyl substances (PFASs) is associated with increased blood cholesterol. Although elevated cholesterol is a well-established risk factor for cardiovascular diseases (CVD), it is not clear whether PFASs affect this risk. Lipoprotein subclasses are emerging biomarkers for disease risk and lipoprotein profiling may provide an insight to physiological implications of PFAS exposure. We explored the association between serum PFAS concentrations and lipoprotein subclasses in a cross-sectional study. We determined the concentrations and lipid composition of the major subclasses of lipoproteins in plasma samples from 127 adult participants of the EuroMix human biomonitoring study by nuclear magnetic resonance (NMR). Serum concentrations of 17 PFASs showed a detection frequency between 30 and 100% and were included in further analyses. We examined the associations between PFAS concentrations and lipoprotein subclasses by linear mixed-effect regression models, adjusted for confounders. In the adjusted models, positive associations were found between several PFASs and cholesterol concentrations in large to medium sized HDL and medium sized LDL particles. We found a 4-12% increase in HDL cholesterol per interquartile range (IQR) increase for several PFASs. In women the associations with PFNA, PFUnDA, PFDoDA and PFOS were significant after adjustment for multiple comparisons. Similar magnitude of change was observed between longer chained PFASs and LDL cholesterol, and a few of these associations reached significance for cholesterol in large to medium LDL particle sizes in women. No significant associations with plasma triglycerides were observed. However, most PFASs tended to be associated with reduction in VLDL (very low-density lipoproteins) particle number and VLDL triglyceride. Findings from this exploratory study, suggest that background PFAS exposures influence particle size distributions and lipid composition of plasma lipoprotein subclasses, and that these effects may be more prominent in women. A two-points lipoprofiling for all subjects indicated both low intra-individual variability and good analytical reproducibility.


Assuntos
Fluorocarbonos , Adulto , Monitoramento Biológico , Colesterol , Estudos Transversais , Feminino , Humanos , Lipoproteínas , Reprodutibilidade dos Testes
7.
Foods ; 11(10)2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35627035

RESUMO

The saponification value of fats and oils is one of the most common quality indices, reflecting the mean molecular weight of the constituting triacylglycerols. Proton nuclear magnetic resonance (1H-NMR) spectra of fats and oils display specific resonances for the protons from the structural patterns of the triacylglycerols (i.e., the glycerol backbone), methylene (-CH2-) groups, double bonds (-CH=CH-) and the terminal methyl (-CH3) group from the three fatty acyl chains. Consequently, chemometric equations based on the integral values of the 1H-NMR resonances allow for the calculation of the mean molecular weight of triacylglycerol species, leading to the determination of the number of moles of triacylglycerol species per 1 g of fat and eventually to the calculation of the saponification value (SV), expressed as mg KOH/g of fat. The algorithm was verified on a series of binary mixtures of tributyrin (TB) and vegetable oils (i.e., soybean and rapeseed oils) in various ratios, ensuring a wide range of SV. Compared to the conventional technique for SV determination (ISO 3657:2013) based on titration, the obtained 1H-NMR-based saponification values differed by a mean percent deviation of 3%, suggesting the new method is a convenient and rapid alternate approach. Moreover, compared to other reported methods of determining the SV from spectroscopic data, this method is not based on regression equations and, consequently, does not require calibration from a database, as the SV is computed directly and independently from the 1H-NMR spectrum of a given oil/fat sample.

8.
Diagnostics (Basel) ; 12(3)2022 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-35328113

RESUMO

Nuclear magnetic resonance (NMR) metabolomics is currently popular enough to attract both specialized and non-specialized NMR groups involving both analytical trained personnel and newcomers, including undergraduate students. Recent interlaboratory studies performed by established NMR metabolomics groups demonstrated high reproducibility of the state-of-the-art NMR equipment and SOPs. There is, however, no assessment of NMR reproducibility when mixing both analytical experts and newcomers. An interlaboratory assessment of NMR quantitation reproducibility was performed using two NMR instruments belonging to different laboratories and involving several operators with different backgrounds and metabolomics expertise for the purpose of assessing the limiting factors for data reproducibility in a multipurpose NMR environment. The variability induced by the operator, automatic pipettes, NMR tubes and NMR instruments was evaluated in order to assess the limiting factors for quantitation reproducibility. The results estimated the expected reproducibility data in a real-life multipurpose NMR laboratory to a maximum 4% variability, demonstrating that the current NMR equipment and SOPs may compensate some of the operator-induced variability.

9.
Int J Mol Sci ; 23(5)2022 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-35269899

RESUMO

Novel fluorescent strigolactone derivatives that contain the piperidine-substituted 1,8-naphthalimide ring system connected through an ether link to a bioactive 3-methyl-furan-2-one unit were synthesized and their spectroscopic properties investigated. The solvatochromic behavior of these piperidine-naphthalimides was monitored in solvents of different polarity using the electronic absorption and fluorescence spectra. These compounds exhibited a strong positive solvatochromism taking into account the change of solvent polarity, and the response mechanism was analyzed by fluorescence lifetime measurements. According to Catalan and [f(n), f(ε), ß, α] solvent scales, the dipolarity and polarizability are relevant to describe the solute-solvent interactions. The emission chemosensing activity was discussed in order to determine the water content in organic environments. The emission intensity of these compounds decreased rapidly in dioxane, increasing water level up to 10%. Measuring of quantum yield indicated that the highest values of quantum efficiency were obtained in nonpolar solvents, while in polar solvents these derivatives revealed the lowest quantum yield. The fluorescence decay can be described by a monoexponential model for low water levels, and for higher water contents a biexponential model was valid.


Assuntos
Naftalimidas , Água , Fluorescência , Naftalimidas/química , Piperidinas , Solventes/química , Espectrometria de Fluorescência , Água/química
10.
Molecules ; 25(22)2020 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-33202577

RESUMO

The paper reports on monitoring methylmalonic aciduria (MMA)-specific and non-specific metabolites via NMR urinomics. Five patients have been monitored over periods of time; things involved were diet, medication and occasional episodes of failing to comply with prescribed diets. An extended dataset of targeted metabolites is presented, and correlations with the type of MMA are underlined. A survey of previous NMR studies on MMA is also presented.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/urina , Espectroscopia de Ressonância Magnética , Metabolômica , Criança , Pré-Escolar , Creatinina/urina , Feminino , Glicina/urina , Humanos , Lactente , Recém-Nascido , Masculino , Fatores de Tempo
11.
Sci Rep ; 10(1): 19827, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33188236

RESUMO

The influence of waste glass and red mud addition as alternative source of aluminosilicate precursors on the microstructural, mechanical, and leaching properties of bottom ash-based geopolymer was studied in this work through mineralogical, morphological, and spectroscopic analysis, as well as by conducting compressive strength and leaching tests. The bottom ash-based geopolymer composites were synthesized by adding a constant amount of waste glass (10% by weight) and increasing amounts of red mud (up to 30% by weight). The results derived from FTIR, 29Si and 27Al MAS NMR, and SEM-EDX revealed that adding up to 10% (by weight) red mud to the synthesis mixes leads to an increase in the degree of geopolymerization of the activated mixes. The compressive strength followed the same trend. An increase of more than 10% (by weight) red mud added to the synthesis mixes results in a significant decrease of compressive strength of the geopolymer composites. A low leachability of geopolymer composites in regard with their contaminants was revealed especially for those with good compressive strength.

12.
Chem Biodivers ; 17(7): e2000175, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32333466

RESUMO

Two chitosan extracts were prepared by chemical and enzymatic treatment of Ganoderma lucidum mushroom, as an alternative source to crustacean shells. The molecular weight of the enzymatic extract was lower than that of the chemical one and of shrimp chitosan, as determined by viscosity measurements. Characteristic signals were identified in the 1 H-NMR spectra and high deacetylation degree indicated good physico-chemical properties for both mushroom chitosan extracts. The scavenging capacity of mushroom chitosan extracts was moderate against the synthetic radicals of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH), but higher values were observed for the enzymatic extract, compared to the chemical extract and shrimp chitosan. In vitro cytotoxicity was evaluated in L929 mouse fibroblast cell lines and the results of MTT assay showed good cytocompatibility in the tested range of concentrations. The growth of Gram-positive bacteria was inhibited more than Gram-negative bacteria in the presence of mushroom chitosan extracts, in particular by the chemical one, indicating their efficiency as antimicrobial agents. All these results strengthen the evidence of mushroom polysaccharide preparations availability for biomedical applications.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Quitosana/farmacologia , Reishi/química , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Benzotiazóis/antagonistas & inibidores , Compostos de Bifenilo/antagonistas & inibidores , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Quitosana/química , Quitosana/isolamento & purificação , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Camundongos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Picratos/antagonistas & inibidores , Relação Estrutura-Atividade , Ácidos Sulfônicos/antagonistas & inibidores
13.
Medicina (Kaunas) ; 55(4)2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30987402

RESUMO

Classic galactosemia is an autosomal recessive disorder caused by the deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT) involved in galactose metabolism. Bacterial infections are a known cause of early morbidity and mortality in children with classic galactosemia. The most common agent is Escherichia coli, but in rare situations, other bacteria are incriminated. We report a case of a three-week-old female patient with galactosemia, who presented with Group B Streptococcus (GBS) meningitis/sepsis. She received treatment with antibiotics, supportive therapy, and erythrocyte transfusion, but after a short period of improvement, she presented acute liver failure with suspicion of an inborn error of metabolism. Rapid nuclear magnetic resonance (NMR) spectroscopy from urine showed highly elevated values of galactose and galactitol. Under intensive treatment for acute liver failure and with a lactose-free diet, her clinical features and laboratory parameters improved considerably. Genetic testing confirmed compound heterozygous status for GALT mutations: c.563 A>G [p.Q188R] and c. 910 C>T, the last mutation being a novel mutation in GALT gene. In countries without an extensive newborn screening program, a high index of suspicion is necessary for early diagnosis and treatment of galactosemia.


Assuntos
Galactosemias/complicações , Galactosemias/genética , Falência Hepática Aguda/complicações , Meningites Bacterianas/complicações , Infecções Estreptocócicas/complicações , UTP-Hexose-1-Fosfato Uridililtransferase/genética , Pré-Escolar , Países Desenvolvidos , Feminino , Seguimentos , Galactitol/urina , Galactose/urina , Galactosemias/dietoterapia , Galactosemias/urina , Humanos , Recém-Nascido , Teste de Tolerância a Lactose , Falência Hepática Aguda/tratamento farmacológico , Espectroscopia de Ressonância Magnética , Meningites Bacterianas/tratamento farmacológico , Mutação , Triagem Neonatal , Romênia , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus
14.
Faraday Discuss ; 209(0): 67-82, 2018 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-29989626

RESUMO

Water uptake in vesicles and the subsequent exchange between water protons and amide -NH protons in amino acids can be followed by a new, highly sensitive, type of magnetic resonance spectroscopy: dynamic nuclear polarisation (DNP)-enhanced NMR in the liquid state. Water hydrogen atoms are detected prior to and after their transfer to molecular sites in peptides and proteins featuring highly-accessible proton-exchangeable groups, as is the case for the -NH groups of intrinsically disordered proteins. The detected rates for amide proton-water proton exchange can be modulated by membrane-crossing rates, when a membrane channel is interposed. We hyperpolarised water proton spins via dynamic nuclear polarisation followed by sample dissolution (d-DNP) and transferred the created polarisation to -NH groups with high solvent accessibility in an intrinsically disordered protein domain. This domain is the membrane anchor of c-Src kinase, whose activity controls cell proliferation. The hindrance of effective water proton transfer rate constants observed in free solvent when a membrane-crossing step is involved is discussed. This study aims to assess the feasibility of recently-introduced hyperpolarised (DNP-enhanced) NMR to assess water membrane crossing dynamics.


Assuntos
Canais Iônicos/química , Peptídeos/química , Proteínas/química , Prótons , Água/química , Espectroscopia de Ressonância Magnética
15.
PLoS One ; 13(7): e0198121, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29990316

RESUMO

Stable Schiff bases containing a furoxan moiety are synthesized as single regioisomers by the reaction of 3-methyl-2-oxy-furazan-4-carbaldehydewith various amino compounds at room temperature. The structures of synthesized compounds were fully characterized by multinuclear NMR spectroscopy and X-ray crystallography. The effect of synthesized Schiff bases containing a furoxan moiety on biological generation of reactive oxygen species and nitric oxide in plant tissues was investigated for the first time by fluorescence microscopy and the released NO identified as nitrite with Griess reagent. There is a good correlation between the biological generation of NO determined by fluorescence microscopy and with Griess reagent. Some of the synthesized compounds exhibited both nitric oxide and reactive oxygen species generation abilities and represent potential NO donors in plant tissues.


Assuntos
Aldeídos/síntese química , Arabidopsis/efeitos dos fármacos , Doadores de Óxido Nítrico/farmacologia , Oxidiazóis/farmacologia , Folhas de Planta/efeitos dos fármacos , Bases de Schiff/farmacologia , Aldeídos/farmacologia , Arabidopsis/química , Arabidopsis/metabolismo , Etilenodiaminas/química , Fluoresceínas/química , Corantes Fluorescentes/química , Microscopia de Fluorescência , Óxido Nítrico/agonistas , Óxido Nítrico/biossíntese , Doadores de Óxido Nítrico/síntese química , Nitritos/agonistas , Nitritos/metabolismo , Oxidiazóis/síntese química , Folhas de Planta/química , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/agonistas , Espécies Reativas de Oxigênio/metabolismo , Bases de Schiff/síntese química , Plântula/química , Plântula/efeitos dos fármacos , Plântula/metabolismo , Sementes/crescimento & desenvolvimento , Estereoisomerismo , Sulfanilamidas/química
16.
Molecules ; 22(6)2017 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-28598371

RESUMO

The importance of strigolactones in plant biology prompted us to synthesize simplified strigolactone mimics effective as exogenous signals for rhizosphere organisms. New strigolactone mimics easily derived from simple and available starting materials in significant amounts were prepared and fully characterized. These compounds contain an aromatic or heterocyclic ring, usually present in various bioactive molecules, connected by an ether link to a furan-2-one moiety. The new synthesized strigolactone mimics were confirmed to be active on plant pathogenic fungi and parasitic weed seeds.


Assuntos
Ascomicetos/efeitos dos fármacos , Materiais Biomiméticos/síntese química , Lactonas/química , Plantas Daninhas/efeitos dos fármacos , Pirimidinas/síntese química , Rizosfera , Ascomicetos/crescimento & desenvolvimento , Materiais Biomiméticos/farmacologia , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Lactonas/isolamento & purificação , Lactonas/farmacologia , Orobanchaceae/efeitos dos fármacos , Orobanchaceae/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/química , Reguladores de Crescimento de Plantas/isolamento & purificação , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Plantas Daninhas/crescimento & desenvolvimento , Pirimidinas/farmacologia , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento
17.
Beilstein J Org Chem ; 13: 659-664, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28487760

RESUMO

Several 3,5-disubstituted isoxazoles were obtained in good yields by regiospecific 1,3-dipolar cycloaddition reactions between aromatic nitrile oxides, generated in situ from the corresponding hydroxyimidoyl chlorides, with non-symmetrical activated alkynes in the presence of catalytic amounts of copper(I) iodide. Effects of 3,5-disubstituted isoxazoles on nitric oxide and reactive oxygen species generation in Arabidopsis tissues was studied using specific diaminofluoresceine dyes as fluorescence indicators.

18.
Beilstein J Org Chem ; 11: 1079-88, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26199663

RESUMO

The three possible structural isomers of 4-(pyridyl)pyrimidine were employed for the synthesis of new pyrrolo[1,2-c]pyrimidines and new indolizines, by 1,3-dipolar cycloaddition reaction of their corresponding N-ylides generated in situ from their corresponding cycloimmonium bromides. In the case of 4-(3-pyridyl)pyrimidine and 4-(4-pyridyl)pyrimidine the quaternization reactions occur as expected at the pyridine nitrogen atom leading to pyridinium bromides and consequently to new indolizines via the corresponding pyridinium N-ylides. However, in the case of 4-(2-pyridyl)pyrimidine the steric hindrance directs the reaction to the pyrimidinium N-ylides and, subsequently, to the formation of the pyrrolo[1,2-c]pyrimidines. The new pyrrolo[1,2-c]pyrimidines and the new indolizines were structurally characterized through NMR spectroscopy. The X-ray structures of two of the starting materials, 4-(2-pyridyl)pyrimidine and 4-(4-pyridyl)pyrimidine, are also reported.

19.
Beilstein J Org Chem ; 10: 2377-87, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25383108

RESUMO

The one-pot three-component reactions of 1-substituted benzimidazoles with ethyl bromoacetate and electron-deficient alkynes, in 1,2-epoxybutane, gave a variety of pyrrolo[1,2-a]quinoxalin-4-ones and pyrrolo[1,2-a]benzimidazoles. The influence of experimental conditions on the course of reaction was investigated. A novel synthetic pathway starting from benzimidazoles unsubstituted at the five membered ring, alkyl bromoacetates and non-symmetrical electron-deficient alkynes in the molar ratio of 1:2:1, in 1,2-epoxybutane at reflux temperature, led directly to pyrrolo[1,2-a]quinoxalin-4-ones in fair yield by an one-pot three-component reaction.

20.
Nat Prod Res ; 28(19): 1619-25, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24971618

RESUMO

The paper describes a new pathway for an efficient synthesis of natural and bioactive drimanic compounds ( - )-pereniporin B (1) and ( - )-cinnamosmolide (2) from ketodiol 7, an intermediate obtained before from accessible labdane diterpenoid (+)-larixol (3). The key step involves allylic bromination of acetate 8 with N-bromosuccinimide. The in vitro antimicrobial and antifungal activities of all compounds are also reported. Their structures were confirmed by both spectroscopic data and chemical transformations.


Assuntos
Antifúngicos/síntese química , Antineoplásicos/síntese química , Sesquiterpenos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Diterpenos/química , Diterpenos/isolamento & purificação , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Sesquiterpenos/química , Sesquiterpenos/farmacologia , Estereoisomerismo
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