113 research outputs found
Synthesis of Enantiopure Methyl (1S,2S,3R,4S,5R)-2-Amino-3,4,5-trihydroxycyclopentanecarboxylate
The 12th International Electronic Conference on Synthetic Organic Chemistry session General Organic SynthesisThe first total synthesis of enantiopure methyl (1S,2S,3R,4S,5R)-2-amino-3,4,5-trihydroxycyclopentanecarboxylate was carried out according to our recent novel strategy for the transformation of nitrohexofuranoses into cyclopentylamines, which is based on an intramolecular cyclization leading to 2-oxabicyclo[2.2.1]heptane derivatives. Differences in reactivity for this key step were rationallized by using molecular mechanism based calculation
Sonogashira versus Stephens-Castro Mediated Synthesis of o-Phenylethynylbenzoic Acids, Convenient Precursors of 3-Phenylisocoumarins
The 12th International Electronic Conference on Synthetic Organic Chemistry session General Organic SynthesisWe describe herein two synthetic approaches to 3-phenyl-5-nitro-isocoumarines, both based on a nitro-facilitated cyclization of o-phenylethynylbenzoic acids obtained by Sonogashira or Stephens-Castro mediated coupling of o-yodobenzoic acids and phenylacetilene
Synthesis of Tetrahydroxyazepanes from Shikimic Acid
The 13th International Electronic Conference on Synthetic Organic Chemistry session General Organic SynthesisWe describe herein a novel synthetical application of shikimic acid, which consist of its transformation into (3R,4S,5R,7S)-7-(hydroxymethyl)azepane-3,4,5-triolWe thank the Spanish Ministry Science and Innovation and the Xunta de Galicia for financial suppor
Invirtiendo la pirámide de las necesidades: la psicología positiva y la nueva lógica del éxito laboral
Antecedents: Positive psychologists claim to have demonstrated a causal relationship between happiness and life success, with the former accounting for why people usually end up better off in life than others, especially at workplace. Method: In this paper we will analyse the role that happiness-based repertoires and techniques provided by
positive psychologists are playing in the current labor sphere. Results: Positive psychologists’ repertoires and techniques do not only meet the emerging demands derived from the changes in the notions of “work” and “worker” in the last decades, but also introduce a whole new logic in the construction of professional workers’ subjectivity, according to which happiness becomes a necessary psychological state that workers must fi rst achieve and develop in order to attain job success at work. Discussion:
This emerging logic does not only circumscribe to the labor sphere, but also refl ects a broader cultural and economic phenomenonAntecedentes: los psicólogos positivos defienden haber demostrado una relación causal entre la felicidad y el éxito en la vida, siendo la primera la razón de por qué hay gente a la que le va mejor que a otra, especialmente en el ámbito del trabajo. Método: analizamos el papel que juegan los repertorios y las técnicas de la felicidad de los psicólogos positivos en el ámbito laboral actual. Resultados: los repertorios y técnicas de los psicólogos positivos no solamente satisfacen las nuevas demandas laborales surgidas en las últimas décadas a raíz de las transformaciones en las nociones de “trabajo” y “trabajador”, sino que
también introducen una lógica completamente nueva de la construcción de la subjetividad de los trabajadores, de acuerdo con la cual la felicidad deviene en un estado psicológico necesario que todo trabajador debe alcanzar y desarrollar con el fin de tener éxito. Discusión: esta lógica emergente, sin embargo, no se circunscribe únicamente al mundo laboral, sino que es síntoma de un fenómeno económico y cultural más ampli
Preliminary Studies on the Synthesis of Rancinamycins from Nitrosugars
The 9th International Electronic Conference on Synthetic Organic Chemistry session General Organic SynthesisWe thank the Spanish Ministry Education and Science for financial support and for a grant José M. Oter
A New Approach to the Synthesis of Benzo[b]naphtho[2,3-b]furan-6,11-diones and 2-Benzyl-3-hydroxynaphthalene-1,4-diones
Here we describe modified syntheses of o-acetylbenzoic
acids and o-acetylphenylacetic acids by Heck palladium-catalysed arylation of n-butyl vinyl ether with o-iodobenzoic acids or with o-iodophenylacetic acids, respectively. General syntheses of benzo[b]naphtho[2,3-b]furan-6,11-diones from o-acetylbenzoic acids and 2-benzyl3-hydroxynaphthalene-1,4-diones from o-acetylphenylacetic acids are
also reported.This work has received financial support from the Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2016–2019, ED431G/09; and Project GRC2014/040), the European Union (Europe- an Regional Development Fund-ERDF), FONDECYT (Research Grants 1161816 and 1141264) and Galchimia S.A.S
A Perturbation of the Dunkl Harmonic Oscillator on the Line
Let Jσ be the Dunkl harmonic oscillator on R (σ>−1/2. For 00, it is proved that, if σ>u−1/2, then the operator U=Jσ+ξ|x|−2u, with appropriate domain, is essentially self-adjoint in L2(R,|x|2σdx), the Schwartz space S is a core of U¯¯¯¯1/2, and U¯¯¯¯ has a discrete spectrum, which is estimated in terms of the spectrum of Jσ¯¯¯¯¯. A generalization Jσ,τ of Jσ is also considered by taking different parameters σ and τ on even and odd functions. Then extensions of the above result are proved for Jσ,τ, where the perturbation has an additional term involving, either the factor x−1 on odd functions, or the factor x on even functions. Versions of these results on R+ are derivedThe first author was partially supported by MICINN, Grants MTM2011-25656 and MTM2014-56950-P, and by Xunta de Galicia, Grant Consolidación e estructuración 2015 GPC GI-1574. The third author has received financial support from the Xunta de Galicia and the European Union (European Social Fund - ESF)S
Grau de cobertura do solo e dinâmica da vegetação em olivais de sequeiro com a introdução de herbicidas
São apresentados resultados do grau de cobertura
do solo e da dinâmica da vegetação
num olival de sequeiro, localizado em Mirandela,
após a introdução de herbicidas como
estratégia de manutenção do solo. As modalidades
em estudo foram: mobilização tradicional;
herbicida pós-emergência (glifosato); e
herbicida com componentes de acção residual
e pós-emergência (diurão+glifosato+terbut
ilazina). O grau de cobertura e a composição
da vegetação foram avaliados desde 2002 a
2007 pelo método do ponto quadrado. Ambas
as soluções herbicidas combateram adequadamente
a vegetação herbácea em aplicação
única anual. O grau de cobertura no talhão
mobilizado, antes da primeira mobilização,
oscilou entre 50 a 80 % e 30 a 60 % debaixo
e fora da copa, respectivamente. O tratamento
com glifosato permitiu um grau de cobertura
em Abril entre 60 a 90 % debaixo da copa e
40 a 50 % fora da copa. No tratamento com
herbicida residual o grau de cobertura do solo
foi sempre muito baixo ao longo do ano. A gestão da vegetação com glifosato permitiu
a cobertura do solo durante todo o ano, com
vegetação viva desde o Outono à Primavera
e um mulching de vegetação morta durante o
Verão. Nas restantes modalidades o solo permaneceu
descoberto durante grande parte do
ano. No talhão gerido com glifosato a vegetação
manteve elevada dinâmica. Um ano após
o início da aplicação de glifosato apareceu a
dominar o coberto Ornithopus compressus.
Com o tempo ganharam importância algumas
espécies de Inverno de ciclo muito curto
(como Mibora mínima e Logfia gallica) e
outras de elevada produção de sementes e fácil
dispersão pelo vento (como Hypochaeris
radicata e Conyza canadensis) com origem
provável em incultos e caminhos que circundam
o olival ou em plantas individuais que
escaparam à acção dos herbicidas. Results of the percentage of ground cover by weeds and the dynamic of the vegetation are presented after the introduction of herbicides as soil management strategies in a rainfed olive orchard. The field experiment was carried out in Mirandela, NE Portugal. The soil management treatments included: conventional tillage; post-emergence herbicide (glyphosate); and post-emergence plus residual herbicide (diuron+glyphosate+terb utilazine). The ground cover percentage and the botanical composition of vegetation were monitored since 2002 to 2007 from the point-quadrat method. Both the herbicide formulations killed efficiently the vegetation in a single annual application. The ground cover percentages in conventional tillage, prior to the first tillage event, varied between 50 to 80 % beneath the trees and between 30 to 60 % in the open space. The ground cover percentages in April, in the treatment of glyphosate, were in the range of 60 to 90 % and 40 to 50 % beneath the trees and between rows, respectively. In the residual herbicide plot the ground cover percentages were always very low. The soil of the glyphosate plot was covered with vegetation over all the year. In au-tumn/spring the soil was covered with green weeds and in the summer with a mulching of the dead material. In the glyphosate plot the dynamic of species was high. One year after the first application of herbicide, Ornithopus compressus appeared as the most abundant species. Thereafter, acquired relevance species with short growing cycles which seeds mature before April (e.g. Mibora minima, Logfia gallica) and other that produce a high number of seeds easily spread by wind (e.g. Hypochaeris radicata, Conyza canadensis) and which seeds proceeded from surrounding untilled fields and rural-tracks or from individual plants that escaped to the herbicide control
New Morphiceptin Peptidomimetic Incorporating (1S,2R,3S,4S,5R)-2-Amino-3,4,5-trihydroxycyclopen-tane-1-carboxylic acid: Synthesis and Structural Study
We present the synthesis and structural study of a new peptidomimetic of morphiceptin, which can formally be considered as the result of the replacement of the central proline residue of this natural analgesic drug with a subunit of (1S,2R,3S,4S,5R)-2-amino-3,4,5-trihydroxycyclopentane-1-carboxylic acid, previously obtained from L-idose. An optimized synthesis of this trihydroxylated cispentacin derivative is also reported. Molecular docking calculations on the target receptor support a favorable role of the hydroxy substituents of the non-natural β-amino acid incorporated into the peptidomimeticThis work has received financial support from the Spanish Ministry of Science and Innovation (CTQ2009-08490), the Xunta de Galicia (Centro Singular de Investigación de Galicia, Centro singular de investigación de Galicia accreditation 2019-2022, ED431G 2019/03; Project CN2011/037, project ED431C 2018/04 and Project GRC2014/040), the Principado de Asturias (FICYT IDI/2018/000181) and the European Union (European Regional Development Fund-ERDF). Partial financial support by Arcelor Mittal (R&D-Principado de Asturias; FUO-286-18). Conicyt research fellowship to ML (PFCHA/Doctorado Nacional/2018-21180427)S
Utilização de boro em olivais de sequeiro
Nos olivais tradicionais de sequeiro de Trás-os-Montes o boro assume papel de importância similar ou mesmo superior a qualquer dos macronutriente N, P e K. Sintomas visíveis do nutriente são usuais e carências dissimuladas, detectadas em análises foliares, são também frequentes. O boro pode ser gerido a partir de aplicações de adubos sólidos ao solo, sprays foliares ou combinando ambas as estratégias
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