Browsing by Autor "Juan M. Amaro‐Luis"

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Absolute structure of two derivatives of a longipinene from<i>Stevia lucida</i>
(Wiley, 2010) Graciela Dı́az de Delgado; Pablo A. Chacón; Juan M. Amaro‐Luis; Hyunsoo Park; José Miguel Delgado
In continuation of our studies of low-melting co-crystals [1], both components of which are liquid under ambient conditions, the crystals of new molecular complexes of chloroform (I) and dichloromethane(II) have been grown in situ and structurally characterized. The structures of new cocrystals of II with cyclohexanone, 1,4-dioxane and butanone-2 are compared with corresponding complexes of I and with the structures of pure components of these co-crystals. In spite of seeming simplicity of the components, the structures display a variety of types and motifs of intermolecular interactions. Indeed, if the (Cl)C-H...O contacts are present in all studied structures, different spatial arrangements of these contacts combined with a delicate balance of weaker interactions of C-H...Cl, C-H...O and even of O...Cl types make the structures of each of these compounds unique, curious and challenging for prediction. Examples of unforeseen products of cocrystallization experiments will also be discussed.
Naphthopyranones from Rhizomes of Paepalanthus diffissus
(2013) José G. Alvarado; José A. Abad-Reyes; Roger Montealegre; Juan M. Amaro‐Luis
Del extracto en diclorometano obtenido de los rizomas de Paepalanthus diffissus Moldenke (Eriocaulaceae)\nfueron aisladas las naftopiranonas bioactivas (+)-semi-vioxantina [3] y vioxantina [8]. Estos compuestos fueron\ncaracterizados en base a estudios espectroscópicos, incluyendo experimentos de RMN uni- y bi-dimensionales.\nLa revisión de la literatura indica que estos metabolitos son encontrados frecuentemente en hongos y líquenes,\npero son compuestos raros en plantas superiores. La presencia de (+)-semi-vioxantina en plantas con flores, es\ndescrita aquí por primera vez.
Productos inesperados en la transformación química de derivados de la podofilotoxona a través de la reacción de Takai.
(2008) Avance De Investigación; José A. Abad-Reyes; José Luis López‐Pérez; Carolina Santiago; Paulino Sánchez Delgado; Alı́ Bahsas; Juan M. Amaro‐Luis
CONTENIDO\n\n\n\n\nEditorial.Algunos logros de "Avances en Química" a sus dos años de aparición. \nLárez Velásquez, Cristóbal\n\n\n\n\nSemblanza\n\n\nOlga y Jairo Márquez: hacedores de ciencia.\nMartínez, Yris J.\n\n\n\nArtículos Científicos\n\n\nAntioxidant and scavenging activity of skyrin on free radical and some reactive oxygen species. \nVargas V., Franklin F.; Rivas, Carlos; Zoltan, Tamara; López, Verónica; Ortega, Jessenia; Izzo, Carla; Pineda, María; Medina, José; Medina, Ernesto y Rosales, Luis\n\n\nOlefin hydroformylation catalysis with RuCl2(DMSO)4.\nReyes, Marisela del C.; Parra, Enrique J.; Fonseca, Y. J.; Fontal, Bernardo; Suárez B., Trino; Bellandi, Fernando; Contreras, Ricardo Rafael; Romero C., Isolda; Prado, Lenis and Cancines, Pedro I.\n\n\nReducción catalítica de NOx con Pt soportado sobre zeolitas MFI modificadas con Cu, Co, Fe, Mn.\nBriceño, Sarah y Del Castillo P., Héctor L.\n\n\n\nAvance de Investigación\n\n\nProductos inesperados en la transformación química de derivados de la podofilotoxona a través de la reacción de Takai.\nReyes, J. Andrés; López Pérez, José Luis; Santiago, Carolina; Delgado Méndez, Paulino; Bahsas B., Alí H.; Amaro, Juan Manuel y Del Olmo, Esther
Profesor Dr. Alí Bahsas Bahsas. Una semblanza sucinta
(Universidad Autónoma del Estado de México, 2009) Juan M. Amaro‐Luis
Sesquiterpene lactones isolated from a medicinal plant of the Venezuelan Andes
(Wiley, 2008) Jaime Delgado; Graciela Dı́az de Delgado; Julia Bruno-Colmenárez; Valentina Cote; Juan M. Amaro‐Luis
Most of nucleoside 5'-monophosphates have been extensively investigated as regards their structure for long, but potassium salts of them have never been studied by the use of X-ray crystallography. The results of structural investigations on five mono-and dipotassium salts of two purine [K2(AMP) . 6H2O, K(IMP) . 3H2O] and two pyrimidine [K2(CMP) . 6.25H2O, K(UMP), K2(UMP) . 5H2O] ribonucleotides will be presented. The K + salts crystallize with Z' = 1-4 for the respective crystal. In all the mono-/dianions, the orientation of the base with respect to the sugar ring is anti, which is typical for nucleotides. The ribose rings in AMP and UMP salts exist in ideal envelope conformations: 2 E in two dianions in K2(AMP) . 6H2O and two dianions in K2(UMP) . 5H2O, and 3 E in the monoanion in K(UMP). The sugar rings in the remaining crystals are slightly deformed from the ideal pucker, with the nearest descriptors being: 3 T2 for the IMP monoanion, 2 T1 for two CMP dianions and 3 T4, 2 E for two remaining CMP dianions. The orientation of the phosphate relative to the ribose ring is the same in all the anions: gauche-gauche, which is characteristic of the 5'-nucleotides. The arrangement of the terminal phosphate atoms relative to the ester C5' is antiperiplanar (ap) for one of O atoms and +/-synclinal (+/-sc) for the others in most of the presented nucleotides. However the phosphate group in the IMP monoanion is disordered and exists in two orientations: typical ap/sc and quite uncommon sp/ac.