997 resultados para Br-PADAP
Resumo:
The counteranion exchange of quaternary 1,2,3-triazolium salts was examined using a simple method that permitted halide ions to be swap for a variety of anions using an anion exchange resin (A¯ form). The method was applied to 1,2,3-triazolium-based ionic liquids and the iodideto- anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Additionally, an anion exchange resin (N3¯ form) was used to obtain the benzyl azide from benzyl halide under mild reaction. Likewise, following a similar protocol, bis(azidomethyl)arenes were also synthesized in excellent yields. The results of a proton NMR spectroscopic study of simple azolium-based ion pairs are discussed, with attention focused on the significance of the charged-assisted (CH)+···anion hydrogen bonds of simple azolium systems such as 1-butyl-3-methylimidazolium and 1-benzyl-3-methyl-1,2,3-triazolium salts.
Resumo:
Invocatio: I.J.N.
Resumo:
This work had as objective verified the term-stability of the Soxhlet modified system with analytical and pharmacothecnical application in extractive processes of Nasturtium officinale. It has proven that the process is thermo-stable. The analysis with analytical have determined 3.606 mg g-1 in chlorogenic acid and 11.813 mg g-1 in rutin (extract 1:20 w/v) and with pharmacotecnical 3.427 mg g-1 in chlorogenic acid and 11.278 mg g-1 in rutin (extract 1:6 w/v). The income of the pharmacothecnical process was inferior to the analytical, suggesting that the pharmacothecnical process would need of at least the double of time in each extraction system.
Resumo:
Invocatio: I.J.N.
Resumo:
Among other applications, Ipomoea pes-caprae is popularly used to treat jellyfish stings, supporting the development of a product for dermatological use. Hydroethanolic spray-dried extract was chosen for the further development of phytomedicines, and a stability-indicative HPLC-UV method was developed and validated for the determination of isoquercitrin and isochlorogenic acids A, B and C. The method was developed using a C18 column (250 x 4.6 mm, 5 µm) with an acetonitrile:water mobile phase at pH 3.0 in a gradient run. The four constituents and other unidentified components of the extract were appropriately resolved without interference of degradation products after stress tests (acid, alkali, neutral, oxidant, photolysis). The method showed linearity in the isoquercitrin concentration range from 5.0-50.0 µg mL-1, with adequate precision (RSD% < 2.5% for the intra- and inter-day studies), accuracy (recovery of 100.0 ± 2.0%), and robustness. Both the herbal drug and spray-dried extract of I. pes-caprae were subjected to stability studies in accelerated and long-term conditions over four months. The samples maintained their characteristics and marker contents (< 10% of variation).
Resumo:
Specimens of Leonotis nepetiflolia were obtained from cultivated and wild environments to verify their influences in chemical composition. Phytochemical analyses were conducted for the ethyl acetate phase obtained by partitioning the crude ethanol extract from the cultivated leaves of L. nepetifolia. In doing so, flavonoid 3',4',5-trimethoxy-6,7-dihidroxyflavone (cirsiliol), a chemotaxonomic marker of the family Lamiaceae, was isolated. The results reveal that all phases and extracts tested exhibited weak to moderate antimicrobial activity against the strains of bacteria tested. The evaluation of in vitrocytotoxic and antitumor activity showed that the ethyl acetate phases obtained from both wild and cultivated leaves exhibit high potential cytotoxic and antitumor (> 78.0% of inhibition) activity. The major component of these phases was identified by high-performance liquid chromatography-diode array detector and nuclear magnetic resonance analyses using both 1D and 2D methods. The results further indicate that the flavonoid cirsiliol is the agent responsible for the activity observed in these phases.
Resumo:
Heterobimetallic carbonyl compounds of the type [Fe(CO)4(HgX)2] (X= Cl, Br, I), which have metal-metal bonds, have been prepared in order to study their thermal stabilities as a function of the halogen coordinated to mercury atoms. The characterization of the above complexes was carried out by elemental analysis, IR and NMR spectroscopies. Their thermal behaviour has been investigated and the final product was identified by IR spectroscopy and by X-ray powder diffractogram.
Resumo:
Este trabalho teve como objetivo avaliar o comportamento da madeira de Grevillea robusta na produção de painéis de madeira aglomerada. Os painéis foram produzidos em densidades de 0,60 e 0,80 g/cm³ e conteúdo de resina de 6 e 8%. Os resultados de propriedades físicas e mecânicas dos painéis fabricados com densidade de 0,80 g/cm³ e conteúdo de resina de 8% evidenciaram que a madeira de Grevillea robusta pode ser utilizada como fonte alternativa de matéria-prima para produção de painéis aglomerados.
Resumo:
14 x 21 cm
Resumo:
17 x 26 cm
Resumo:
18 x 26 cm