oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Síntese de 2-iodobenzamidas e 3-(iodoacetamido)benzamidas ligadas à D-galactose e suas rea??es de carbocicliza??o radicalar mediadas por hidreto de tri-n-butilestanho
Leal, Daniel Henriques Soares;Queiroga, Carla Graziella;Pires, Magno Carvalho;Prado, Maria Auxiliad?ra Fontes;Alves, Ricardo José;Cesar, Amary;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000900029
Abstract: starting from methyl 6-o-allyl-4-azido-2,3-di-o-benzyl-4-deoxy-α-d-galactopyranoside, four new derivatives containing 2-iodobenzamido and 3-(iodoacetamido)benzamido groups were synthesized. these four compounds were submitted to tri-n-butyltin hydride mediated radical cyclization reactions, resulting in two macrolactams from 11- and 15-endo aryl radical cyclization. the corresponding four hydrogenolysis products were also obtained. the structures of the new compounds were elucidated by 1h and 13c nmr spectroscopy, dept, cosy, hmqc and hmbc experiments.
Rea??es de carbocicliza??o radicalar de orto-iodoaliloxibenzoatos derivados de d-glicose e d-galactose e compara??o com as rea??es de seus análogos benzamidas
Binatti, Ildefonso;Alves, Rosemeire Brondi;Souza Filho, José Dias de;Dias, Danielle Ferreira;Prado, Maria Auxiliad?ra Fontes;Alves, Ricardo José;
Química Nova , 2005, DOI: 10.1590/S0100-40422005000600017
Abstract: two ortho-iodoallyloxybenzoates, methyl 4-o-allyl-2,3-di-o-benzyl-6-o-(2-iodobenzoyl)- a-d-glucopyranoside (3) and methyl 4-o-allyl-2,3-di-o-benzyl-6-o-(2-iodobenzoyl)- a-d-galactopyranoside (4) were synthesized in seven conventional steps from methyl a-d-glucopyranoside and methyl a-d-galactopyranoside, respectively. bu3snh-mediated aryl radical cyclization of 3 provided exclusively the hydrogenolysis product 12. the reaction of 4 gave the reduced uncyclized product 13 and only traces of 4a, resulting from 11-endo aryl radical cyclization. in previous papers we described that in similar bu3snh-mediated radical reaction of ortho-iodoallyloxybenzamides, analogs of 3 and 4, we obtained macrolactams resulting from 11-endo cyclization. an hypothesis to explain the differences is presented. it was assumed that in the aryl radical formed from iodobenzamides there is a suitable conformation to cyclization, which is stabilized by an intramolecular hydrogen bond.
Síntese de aliloxi-orto-iodobenzamida derivada de d-glicose e rea??o de cicliza??o radicalar mediada por hidreto de tri-n-butilestanho
Dias, Danielle Ferreira;Prado, Maria Auxiliad?ra Fontes;Pinto, Gleydson Daniel;Alves, Ricardo José;Alves, Rosemeire Brondi;Souza Filho, José Dias de;
Química Nova , 2006, DOI: 10.1590/S0100-40422006000300008
Abstract: methyl 6-o-allyl-2,3-di-o-benzyl-4-deoxy-4-(2 -iodobenzoylamine)-a-d-glucopyranoside was synthesized in nine conventional steps from methyl a-d-glucopyranoside. its bu3snh-mediated aryl radical cyclization provided a benzomacrolactam, resulting from 11-endo aryl radical cyclization and the reduced uncyclized product methyl 6-o-allyl-4-benzoylamine-2,3-di-o-benzyl-4-deoxy- a-d-glucopyranoside. the structures of the three new products were supported by 1h and 13c nmr spectroscopy and dept, cosy and hmqc experiments.
Rea es de carbocicliza o radicalar de orto-iodoaliloxibenzoatos derivados de d-glicose e d-galactose e compara o com as rea es de seus análogos benzamidas  [cached]
Binatti Ildefonso,Alves Rosemeire Brondi,Souza Filho José Dias de,Dias Danielle Ferreira
Química Nova , 2005,
Abstract: Two ortho-iodoallyloxybenzoates, methyl 4-O-allyl-2,3-di-O-benzyl-6-O-(2-iodobenzoyl)- alpha-D-glucopyranoside (3) and methyl 4-O-allyl-2,3-di-O-benzyl-6-O-(2-iodobenzoyl)- alpha-D-galactopyranoside (4) were synthesized in seven conventional steps from methyl alpha-D-glucopyranoside and methyl alpha-D-galactopyranoside, respectively. Bu3SnH-mediated aryl radical cyclization of 3 provided exclusively the hydrogenolysis product 12. The reaction of 4 gave the reduced uncyclized product 13 and only traces of 4A, resulting from 11-endo aryl radical cyclization. In previous papers we described that in similar Bu3SnH-mediated radical reaction of ortho-iodoallyloxybenzamides, analogs of 3 and 4, we obtained macrolactams resulting from 11-endo cyclization. An hypothesis to explain the differences is presented. It was assumed that in the aryl radical formed from iodobenzamides there is a suitable conformation to cyclization, which is stabilized by an intramolecular hydrogen bond.
Síntese de aliloxi-orto-iodobenzamida derivada de d-glicose e rea o de cicliza o radicalar mediada por hidreto de tri-n-butilestanho  [cached]
Dias Danielle Ferreira,Prado Maria Auxiliad?ra Fontes,Pinto Gleydson Daniel,Alves Ricardo José
Química Nova , 2006,
Abstract: Methyl 6-O-allyl-2,3-di-O-benzyl-4-deoxy-4-(2 -iodobenzoylamine)-alpha-D-glucopyranoside was synthesized in nine conventional steps from methyl alpha-D-glucopyranoside. Its Bu3SnH-mediated aryl radical cyclization provided a benzomacrolactam, resulting from 11-endo aryl radical cyclization and the reduced uncyclized product methyl 6-O-allyl-4-benzoylamine-2,3-di-O-benzyl-4-deoxy- alpha-D-glucopyranoside. The structures of the three new products were supported by 1H and 13C NMR spectroscopy and DEPT, COSY and HMQC experiments.
Terpenóides e avalia??o do potencial antimalárico, larvicida, anti-radicalar e anticolinesterásico de Pouteria venosa (Sapotaceae)
Montenegro, Livya Holanda M.;Oliveira, Patrícia Emanuella S.;Conserva, Lucia M.;Rocha, Eliana Maria M.;Brito, Ana Cristina;Araújo, Renata M.;Trevisan, Maria Teresa S.;Lemos, Rosangela P. Lyra;
Revista Brasileira de Farmacognosia , 2006, DOI: 10.1590/S0102-695X2006000500005
Abstract: this work describes the isolation of four triterpenes (taraxerol, ursolic acid, 3b,19a,23-trihydroxyurs-12-en-28-oic acid and 2a,3a,19a,23-tetrahydroxyurs-12-en-28-oic acid) and a phytosteroid (spinasterol), as well as a preliminary evaluation of antimalarial (nk-65 strains of plasmodium berghei), larvicidal (4th instar of aedes aegypti), anti-radicalar (2,2-diphenyl-1-pycryl-hydrazyl, dpph) and anticholinesterase activities of pouteria venosa (mart.) baehni extracts from leaves, stem barks and stems. all isolated compounds are being described for the first time in this species and were identified on basis of the spectral data (ir and nmr, including apt, dept), as well as by comparison with literature data.
Química supramolecular de los compuestos obtenidos por la combinación entre los macrociclos poliaza y los ácidos aromáticos  [cached]
Elena V. Basiuk,Jacobo Gómez Lara,Vladimir A. Basiuk
Revista de la Sociedad Química de México , 2000,
Abstract: Se presentan los resultados recientes sobre la síntesis y caracterización de la estructura cristalina para los nuevos materiales obtenidos por la combinación entre los macrocíclos poliaza (ligantes libres y complejos metálicos) y los ácidos aromáticos, con enfoque al papel de los enlaces de hidrógeno en la formación de las redes supramoleculares extensas.
Nuevos compuestos semiconductores. Síntesis, caracterización y estudio comparativo del comportamiento eléctrico de macrociclos de Niquel(II) del tipo...
M.Elena Sánchez Vergara,Jacobo Gómez Lara,Verónica García Montalvo,Armando Ortíz Rebollo
Revista de la Sociedad Química de México , 2000,
Abstract: El presente trabajo se refiere a la síntesis, caracterización y evaluación de propiedades eléctricas y ópticas de compuestos del tipo de los complejos de J ger; [Ni(C17H25N4OL)](PF6)2 (L = NH (CH2)2NH2, NH(CH2)4NH2, NH(CH2)12NH2, NHC14H6O2NH2). Los compuestos se sintetizaron a partir del macrociclo [Ni(C18H28N4 O2)](PF6)2 (1) y de las correspondientes aminas bidentadas. La caracterización química se llevó a cabo por espectroscopía IR y UV-Vis, análisis elemental, susceptibilidad magnética y difracción de rayos X de polvos. Todos los compuestos son diamagnéticos y presentan la transición d-d en el visible, que corresponde a la geometría cuadrado plana para un Ni(II) tetracoordinado. Los resultados de IR indican que las aminas empleadas se unen al macrociclo a través de uno sólo de sus extremos. Por otra parte, la evaluación de las propiedades eléctricas de los compuestos sintetizados reveló un comportamiento semiconductor. Las magnitudes de conductividad eléctrica se localizan en el intervalo reportado para este tipo de materiales. Las energías de activación de la conductividad eléctrica se asocian con energías necesarias para deslocalizar electrones, mientras que el ancho de banda de las energías prohibidas adquieren valores desde 1.5 hasta 2.49 eV.
LASSBio ’s contribution in the development of novel antiasthmatic prototypes drug candidates [A Contribui o do LASSBio no desenvolvimento de novos candidatos a protótipos de fármacos antiasmáticos]  [cached]
Lidia Moreira Lima,Natália de Lima Medeiros
Revista Virtual de Química , 2009,
Abstract: In this paper will be described the physiopathological aspects of asthma and the main results obtained by the Laboratório de Avalia o e Síntese de Substancias Bioativas (LASSBio ) in the discovery of novel antiasthmatic prototypes drug candidates, using physiological approach as an strategy to rational drug design.
Tetraazamacrocyclic Complexes of Tin(II): Synthesis Spectroscopy and Biological screening  [cached]
ASHU CHAUDHARY,RATAN SWAROOP,R. SINGH
Boletín de la Sociedad Chilena de Química , 2002,
Abstract: Sixteen to eighteen membered tetraamide macrocyclic ligands N4L1 and N4L2 have been prepared by the condensation of 1,2-diaminoethane or 1,3-diaminopropane with phthalic acid in the presence of condensing reagents dicyclohexylcarbodiimide and 4- dimethylaminopyridine. On reduction, these macrocyclic ligands give new tetraazamacrocycles N4L3 and N4L4 which form complexes with tin(II) chloride. The macrocyclic ligands and their complexes have been characterized by elemental analysis, molecular weight determinations, conductance, IR and 1H NMR spectral studies. The spectral data suggested hexacoordinated state for tin in these complexes. Conductivity data suggested that they behave as non-electrolytes. An octahedral geometry for these complexes has been proposed as the binding sites are the nitrogen atoms of the macrocycles. The formulation of the complexes of the type [Sn(N4Ln)Cl2] has been established on the basis of chemical composition. The ligands and their complexes have been screened in vitro against a number of pathogenic fungi and bacteria to assess their growth inhibiting potential Se han preparado ligandos tetraaza macrociclicos de entre 16 a 18 minbros, por condensación de 1,2-diaminoethane o 1,3-diaminopropano con acido ftalico in presencia de de los reactivos condensantes diciclohexilcarbodimida y 4-dimetilaminopiridina. Reducción de estos macrociclos dio nuevos tetraaza macrociclos N4L3 y N4L4 los cuales forman complejos con cloruro de Sn(II). Estos macrociclos y sus complejos han sido caracterizados por análisis elemental, determinaciones de pesois moleculares, conductividad y espectros IR y 1 H NMR. La data espectroscopica sugiere que una hexacoordinación para el esta o en estos complejos. Los datos de conductividad indican que ellos se comportan como no electrolitos. Se propone una geometría octahedrica ya que los sitios de coordinación son los nitrógenos de los macrociclos. La formulación de los complejos como [Sn(N4Ln)Cl2] se ha establecido a partir de los datos de la composición química. Los ligandos y sus complejos han sido usados, in vitro, para determinar su potencial inhibidor de crecimiento de hongos y bacterias
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.