Browsing by Author "Bravo, Héctor R."
Now showing items 1-17 of 17
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Bravo, Héctor R.; Copaja, Sylvia V.; Figueroa-Duarte, Sebastián; Lamborot, Madeleine; San Martín, Joxsé (Verlag der Zeitschrift fur Naturforschung, 2005)Secondary metabolites, DIBOA, HBOA, 7-OH-HBOA, BOA and gallic acid, were isolated and quantified from Calceolaria thyrsiflora Graham, a native medicinal plant of Chile belonging to the Scrophulariaceae family. The highest ...
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Gómez Jeria, Juan; Bravo, Héctor R. (Scholars Research Library, 2016)We employed a formal QSAR method to find the main interactions regulating the variation of the ability to inhibit the germination of Lactuca sativa seeds by a small group of phenolic acids. The same techique was employed ...
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Bravo, Héctor R.; Weiss-López, Héctor R.; Valdebenito-Gamboa, Javier; Gómez Jeria, Juan (Research Journal of Pharmaceutical, Biological and Chemical Sciences, 2016)Allelopathic effects of a chemical compound strongly depends on the target species, dose or concentration employed, structure of the molecule and physical properties, such as water solubility, lipophilicity and others. In ...
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Copaja, Sylvia V.; Bravo, Héctor R.; Muñoz, Paola (Sociedad Chilena de Quimica, 2012)The efficiency of the adsorption process of the fungicides Captan and Thiram was studied in four Chilean soils from the VI [O'Higgins, (HGS)], VII [Talcarehue, (THL)], VIII [Diguillin, (DIG)] and Metropolitan [Maipo, (MAO)] ...
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Atkinson, Jeffrey; Morand, Peter; Arnason, John T.; Niemeyer, Hermann M.; Bravo, Héctor R. (1991)Analogues of the aglucones of naturally occurring cyclic hydroxamic acids (2,4-dihydroxy-1,4-benzoxazin-3-ones) from Gramineae (Poaceae) have been synthesized by the reductive cyclization of the ring-substituted methyl ...
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Bravo, Héctor R.; Lazo, Waldo (American Chemical Society, 1996)Natural hydroxamic acids and related compounds derived from 1,4-benzoxazin-3-one structures inhibited the growth of the alga Chlorella xanthella and the fungus Candida albicans. On the basis of structure-activity relationships ...
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Bravo, Héctor R.; Copaja, Sylvia V.; Lazo, Waldo (American Chemical Society, 1997)Natural 2-benzoxazolinones BOA and MBOA and related synthetic derivatives inhibited the growth of Staphylococcus aureus, Escherichia coli, and Candida albicans. Both the electrophilic character of the nitrogen atom of the ...
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Niemeyer, Hermann M.; Pesel, Erika; Copaja, Sylvia V.; Bravo, Héctor R.; Franke, Stephan; Francke, Wittko (1989)Seedlings of four wheat cultivars were infested with Metopolophium dirhodum nymphs. After aphids had fed for 40 hr on the plants, the levels of the defense metabolite 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one had changed. ...
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Bravo, Héctor R.; Copaja, Sylvia V.; Argandoña, Victor H. (2004)Natural hydroxamic acids and related compounds derived from the 1,4-benzoxazin-3-one structure show antifeedant activity against the aphid Rhopalosiphum padi. This antifeeding activity is based on the electrophilic character ...
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Bravo, Héctor R.; Villarroel, Elisa; Copaja, Sylvia V.; Argandoña, Victor H. (Verlag der Zeitschrift fur Naturforschung, 2008)Germination inhibition activity of N-aryl hydroxamic acids and acetanilide analogues was measured on lettuce seeds (Lactuca sativa). Lipophilicity of the compounds was determined by HPLC. A correlation between lipophilicity ...
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Bravo, Héctor R.; Copaja, Sylvia V.; San Martín, José (Verlag der Zeitschrift fur Naturforschung, 2004)Secondary metabolites, DIBOA, HBOA, 7-OH-HBOA and BOA, were isolated and quantified from S. dulce (Nees), a native species in Chile belonging to the Acanthaceae family. The highest DIBOA and HBOA contents were determined ...
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Bravo, Héctor R.; Niemeyer, Hermann M. (1985)The decomposition of the title compound (DIMBOA, 1) in aprotic solvents was analysed in terms of linear solvation energy relationships using donor numbers. The results indicate rate-limiting cyclic hemiacetal opening in ...
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Bravo, Héctor R.; Niemeyer, Hermann M. (1991)Kinetic and product studies indicate that the title compound decomposes in aqueous solutions to give 5-nitro-2-aminophenol with the intermediacy of N-(2-hydroxy-4-nitrophenyl)carbamic acid. © 1991.
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López Serrano, María Lourdes (Universidad de Chile, 2019-09)La alelopatía es una de las alternativas utilizadas para el manejo integrado de malezas (MIM), con el fin de minimizar el uso de herbicidas sintéticos. La alelopatía, se define como el efecto que produce un químico ...
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Bravo, Héctor R.; Niemeyer, Hermann M. (1986)Solubilities and IR spectra of DIMBOA in alcoholic solvents showed that the carbonyl group of DIMBOA is hydrogen-bonded to the solvent. Activation parameters of DIMBOA in the same solvents suggested that the decomposition ...
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Tessada Sepúlveda, Roxana Magdalena (Universidad de Chile, 2004)El suelo es uno de los recursos más importantes que existen en la naturaleza, desafortunadamente, muchos suelos del mundo se encuentran en un nivel avanzado de degradación por la falta de cuidado en su utilización. Uno ...
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Weiss López, Boris; Bravo, Héctor R. (1994)AM1 full geometry optimization of seven substituted cyclic hydroxamic acids (Hx) was performed. A qualitative correlation between Elumo vs Hammett's σP was observed. The reactivity of these 7-substituted Hx with hard ...