Sample records for HALUROS (halides)
from WorldWideScience.org

Sample records 1 - 14 shown.



1

ESTUDIO EXPERIMENTAL Y TEÓRICO DE LA SÍNTESIS DE N-ALQUIL-NITROIMIDAZOLES/ EXPERIMENTAL AND THEORETICAL STUDY OF SHYNTESIS OF N-ALKYL-NITROIMIDAZOLES.

SALAMANCA M, Constain; TIZNADO V, William; JARAMILLO G, Paula
2010-05-01

Resumen en español En este trabajo se realizó un estudio experimental y teórico sobre la N-alquilación de nitroimidazoles. Los N-alquil-2-metil-nitroimidazoles corresponden a moléculas con actividad biológica, que se obtienen por la reacción del 2-metil-5-nitroimidazol y diferentes halogenuros de alquilo. En esta reacción se observó la formación de una mezcla de productos isoméricos en diferente proporción, denominados como N-alquil-2-metil-4-nitroimidazol y N-alquil-2-metil-5-ni (mas) troimidazol, respectivamente. La reacción sugiere la formación de un equilibrio tautomérico, que genera dos sitios nucleofílicos susceptibles a un ataque electrofílico por parte del halogenuro de alquilo. La reactividad local nucleofílica del anillo nitroimidazólico se determinó utilizando índices de reactividad local, como la función de Fukui y el potencial electrostático, además de la función de localización electrónica (ELF). La función de Fukui se integra en los átomos utilizando los esquemas de partición basados en el análisis de cargas de Mulliken y orbitales naturales de enlace (NBO). Por último, se evaluaron los perfiles de reacción. Los resultados mostraron una leve diferencia en la reactividad local, sin embargo, se observan diferencias significativas en las barreras energéticas, que explican la formación de un producto isomérico sobre el otro, encontrándo así, concordancia entre los resultados experimentales y los teóricos. Resumen en inglés In this work we realized and experimental and theoretical study of the N-alkylation of nitroimidazoles. The N-alkyl-2-methyl-nitroimidazoles correspond to biologically active molecules, obtained by reaction of 2-methyl-5-nitroimidazole and different alkyl halides. This reaction showed the formation of a mixture of isomeric products in different proportions, denominated like N-alkyl-2-methyl-4-nitroimidazole and N-alkyl-2-methyl-5-nitroimidazole, respectively. The reaction (mas) suggestes the formation of a tautomeric equilibrium, which generates two nucleophilic sites susceptible to electrophilic attack by the alkyl halide. The local nucleophilic reactivity of the nitroimidazole ring is determined using local reactivity indices such as the Fukui function and the electrostatic potential, besides the electronic localization function (ELF). The Fukui function was integrated for each atom using partition schemes based on analysis of Mulliken charges and natural bond orbital (NBO). Finally the reaction profiles were assessed. The results show a minor difference in the local reactivity. Nevertheless a significant difference in energy barriers is observed explaining the formation of an isomeric product over another. These results agree quite well with the experimental data.

Scientific Electronic Library Online (Spanish)

3

Study of the presence of fluorine in the recycled fractions during carbothermal treatment of EAF dust

Menad, N.; Ayala, J. Nancy; Garcia Carcedo, Fernando; Ruiz-Ayúcar, E.; Hernández Fernández, Ángel
2003-01-01

Digital.CSIC (Spain)

4

Structural relationships between cations and alloys; an equivalence between oxidation and pressure

Vegas, Ángel; Jansen, M.

More than 100 examples are provided of the structural identity between the cation arrays in oxides and their corresponding alloys (binary compounds). Halides and halogenates, sulfides and sulfites and/or sulfates, selenides and selenates, phosphides and phosphates show this behaviour. In some cases,...

DRIVER (Spanish)

7

Porous crystal structures obtained from directionally solidified eutectic precursors.

Larrea Arbáizar, Ángel; Orera Clemente, Víctor Manuel
2007-03-15

Digital.CSIC (Spain)

9

Phosphonium ionic liquids: design, synthesis and evaluation of biodegradability

Atefi, Farzad; García, M. Teresa; Singer, Robert D.; Scammells, Peter J.
2009-07-21

Digital.CSIC (Spain)

10

Mixed P−N and as−N bis-ylide palladium complexes: Cooperative intramolecular interactions, conformational preferences, and C−H bond activations

Serrano, Elena; Vallés, Cristina; Carbó, Jorge J.; Lledós, Agustí; Soler, Tatiana; Navarro, Rafael; Urriolabeitia, Esteban P.
2006-08-01

Digital.CSIC (Spain)

12

From a trinuclear platinum(III) phosphido derivative to a platinum(II) cluster: Formation of a P−C bond

Forniés, Juan; Fortuño, Consuelo; Ibáñez, Susana; Martín, Antonio
2006-04-01

Digital.CSIC (Spain)

13

Fragmentation of carbohydrate anomeric alkoxy radicals: A new synthesis of chiral 1-halo-1-iodo compounds

González Martín, Concepción C.; Kennedy, Alan R.; León, Elisa I.; Riesco-Fagundo, Concepción; Suárez, Ernesto
2001-06-13

Digital.CSIC (Spain)

14

Comparative analysis of the microbial communities inhabiting halite evaporites of the Atacama Desert

Ríos, Asunción de los; Valea, Sergio; Ascaso, Carmen; Dávila, Alfonso; Kastovsky, Jan; McKay, Christopher P.; Wierzchos, Jacek
2010-01-01

Digital.CSIC (Spain)