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1.
JMIR Res Protoc ; 8(2): e10823, 2019 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-30789352

RESUMEN

BACKGROUND: Increasing proportions of the global population transition through a university setting, a setting associated with engagement in behaviors that diminish health such as high levels of physical inactivity. Increasing physical activity (PA) is a key element of health promotion strategies in many countries, but a better understanding of students' PA and how it is associated with personal, behavioral, and environmental factors is needed. Studies provide protocols to collect information regarding these factors separately; however, none have developed a validated systematic approach to gather information pertaining to all across a whole country. OBJECTIVE: The purpose of this project is to examine students' physical activity and how it is associated with personal, behavioral, and environmental factors. METHODS: Student Activity and Sport Study Ireland (SASSI) is a university-based cross-sectional study that was carried out across the island of Ireland in 2014. A novel and comprehensive Web-based environmental audit tool (EAT) gathered information pertaining to the environment provided by universities for physical activity. A Web-based student survey (SS) collected information about physical activity beliefs, attitudes, motivations, and behaviors of students. The audit tool and SS were developed through rigorous consultation processes involving international experts. An institutional champion volunteered at each university to recruit, administer, and ensure the completion of both assessments. RESULTS: Data collection was undertaken between May and December 2014. A total of 80% (33/41) of universities completed the EAT, whereas 88.31% (8122/9197) of students (49.10% [3966/8122] male; mean 23.17 [SD 6.75], years) completed the SS sufficiently. Studies are currently underway with the data collected using this protocol. CONCLUSIONS: SASSI provides a novel and comprehensive protocol for systematically assessing the PA of students and the related personal, behavioral, and actual environmental factors. The strengths of the SASSI study are presented and include high response rates and a unique dataset that can provide information to relevant stakeholders and policy makers, along with aiding the development of university environments and interventions that promote PA involvement. The weaknesses of the protocol are recognized with suggestions given to overcome them in future research. This protocol is applicable for other countries and has great potential to create harmonization of data, which would allow for direct comparisons across nations. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/10823.

2.
J Am Chem Soc ; 130(41): 13549-51, 2008 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-18798628

RESUMEN

Computational studies at the BLYP/6-31G(d) level (supplemented by BCCD(T)/cc-pVDZ calculations) suggest that in aryl-substituted 1,2-diethynylbenzenes, steric effects disfavor the thermal C1-C6 diradical cyclization reaction (Bergman) and electronic effects favor the regiovariant C1-C5 cyclization to the extent that the C1-C5 process should become an important reaction pathway in the thermolyses of such compounds. Experimentally, thermolyses of 1,2-bis(2,4,6-trichlorophenylethynyl)benzene, a particularly favorable case, yields only products derived from C1-C5 cyclization [specifically, 1-(2,4,6-trichlorobenzylidene)-2-(2,4,6-trichlorophenyl)-1H-indene and its hydrogenation product 3-(2,4,6-trichlorobenzyl)-2-(2,4,6-trichlorophenyl)-1H-indene], and even for the parent hydrocarbon 1,2-bis(phenylethynyl)benzene, the formation of C1-C5 cyclization products is competitive with the major Bergman reaction. Although some C1-C5 cyclization products are probably formed by transfer hydrogenation from 1,4-cyclohexadiene (commonly included in such reactions), thermolyses in the absence of 1,4-CHD as well as deuterium labeling studies confirm the existence of direct C1-C5 diradical cyclizations for diaryl-substituted enediynes.


Asunto(s)
Carbono/química , Enediinos/química , Temperatura , Alcadienos/química , Cristalografía por Rayos X , Ciclización , Radicales Libres/química , Modelos Moleculares , Estructura Molecular
3.
J Am Chem Soc ; 130(48): 16435-41, 2008 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-18998648

RESUMEN

Two strategies for the synthesis of configurationally stable twisted polycyclic aromatic compounds (PACs) were pursued. The first approach employed dissymmetrically positioned 1-naphthyl substituents to bias the direction of twist in highly substituted PACs. 2,3-Bis(1-naphthyl)-1,4-diphenyltriphenylene (7) was prepared, and its meso cis-dinaphthyl and enantiomeric trans-dinaphthyl isomers were resolved by preparative supercritical fluid chromatography (SFC) on chiral supports. Similarly, several naphthyl-substituted derivatives of the more highly twisted 9,10,11,12,13,14-hexaphenylbenzo[b]triphenylene (2) were prepared. Of these, 10-(1-naphthyl)-9,11,12,14-tetraphenylbenzo[b]triphenylene (13) was resolved by SFC on a chiral support. The pure enantiomers of trans-7 showed moderately large specific rotations ([alpha]D(25) = -330 and +320 degrees), but the specific rotations for the enantiomers of 13 were unexpectedly small ([alpha]D(25) = -23 and +23 degrees). Computational studies suggest that the latter result is due to presence of a minor conformation of 13 possessing a larger rotation of opposite sign than the major conformation. Both 7 and 13 showed strong circular dichroism and moderately strong circularly polarized luminescence. A byproduct of these syntheses was 9,10,19,21-tetraphenyldiphenanthro[9,10-b:9,10-h]carbazole (15), a very crowded carbazole that exhibits an 81 degree end-to-end twist but is not resolvable. In the second approach, the large, twisted, polycyclic aromatic ligand 9,10,11,12,13,14-hexaphenylbenzo[h]naphtho[2,3-f]quinoline (21, an aza-2) was used to prepare the chiral, cyclometallated iridium(III) complex 4. The ligand 21 was prepared via an unusually stable benzannulated norbornadienone, for which the free energy of activation for decarbonylation was a remarkable 33.5 kcal/mol. The iridium complex 4 proved to be configurationally stable and resolvable by analytical HPLC on chiral supports, but the low solubility of 4 prevented its resolution on a preparative scale. A much more soluble dibutyl analogue of 4 (complex 28) was then prepared, but it was not resolvable on any of the available media.

4.
Artículo en Inglés | MEDLINE | ID: mdl-18676209

RESUMEN

2,2,2-Trifluoroethanol (TFE) is evaluated as an alternative modifier for the analysis and purification of alcohol-sensitive chiral compounds using supercritical fluid chromatography (SFC). Four chiral compounds, selected for their sensitivity to alcohols, in addition to a variety of standard chiral compounds were analyzed by SFC using TFE with polysaccharide and Pirkle-type chiral stationary phases (CSPs) to produce selectivities (alpha) and resolutions (Rs) as high as 1.4 and 7.2. A preparative isolation of 2-phenylglutaric anhydride was achieved using TFE as the mobile phase modifier to produce clean enantiomers.


Asunto(s)
Anhídridos/aislamiento & purificación , Cromatografía con Fluido Supercrítico/métodos , Glutaratos/aislamiento & purificación , Trifluoroetanol/química , Preparaciones Farmacéuticas/aislamiento & purificación , Estereoisomerismo
5.
J Chromatogr A ; 1100(1): 108-15, 2005 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-16197954

RESUMEN

The carbobenzyloxy (cbz) protecting group is evaluated for it's potential to enhance the resolution of chiral amine enantiomers using high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). A series of cbz derivatives of commercially available racemates was prepared and analyzed by enantioselective chromatography using a variety of mobile phases and polysaccharide and Pirkle-type chiral stationary phases (CSPs). The cbz-derivatized product consistently demonstrated enhanced chiral resolution under HPLC and SFC conditions. Improved selectivity and resolution combined with an automated preparative HPLC or SFC system can lead to the rapid generation of highly purified enantiomers of desirable starting materials, intermediates or final products.


Asunto(s)
Aminas/química , Cromatografía Líquida de Alta Presión/métodos , Cromatografía con Fluido Supercrítico/métodos , Estereoisomerismo
6.
Inorg Chem ; 47(6): 2039-48, 2008 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-18271527

RESUMEN

A family of heteroleptic (C;N)2Ir(acac) and homoleptic fac-Ir(C;N)3 complexes have been synthesized and their photophysical properties studied (where C;N = a substituted 2-phenylpyridine and acac = acetylacetonate). The neutral Delta and Lambda complexes were separated with greater than 95% enantiomeric purity by chiral supercritical fluid chromatography, and the solution circular dichroism and circularly polarized luminescence spectra for each of the enantio-enriched iridium complexes were obtained. The experimentally measured emission dissymmetries (gem) for this series compared well with predicted values provided by time-dependent density functional theory calculations. The discovered trend further showed a correlation with the dissymmetries of ionic, enantiopure hemicage compounds of Ru(II) and Zn(II), thus demonstrating the applicability of the model for predicting emission dissymmetry values across a wide range of complexes.

7.
Chirality ; 19(9): 658-82, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17390370

RESUMEN

The application of Chiral Technology, or the (extensive) use of techniques or tools for the determination of absolute stereochemistry and the enantiomeric or chiral separation of racemic small molecule potential lead compounds, has been critical to successfully discovering and developing chiral drugs in the pharmaceutical industry. This has been due to the rapid increase over the past 10-15 years in potential drug candidates containing one or more asymmetric centers. Based on the experiences of one pharmaceutical company, a summary of the establishment of a Chiral Technology toolbox, including the implementation of known tools as well as the design, development, and implementation of new Chiral Technology tools, is provided.


Asunto(s)
Química Farmacéutica/métodos , Industria Farmacéutica/métodos , Estereoisomerismo , Cromatografía/métodos , Dicroismo Circular , Diseño de Fármacos , Electrones , Humanos , Espectroscopía de Resonancia Magnética/métodos , Modelos Químicos , Conformación Molecular , Sales (Química)/farmacología , Tecnología Farmacéutica/métodos
8.
J Am Chem Soc ; 128(51): 17043-50, 2006 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-17177456

RESUMEN

9,10,11,20,21,22-hexaphenyltetrabenzo[a,c,l,n]pentacene (2) and a dimethyl derivative (2m) were prepared by the reaction of 1,3-diphenylphenanthro[9,10-c]furan with bisaryne equivalents generated from 1,2,4,5-tetrabromo-3,6-diarylbenzenes in the presence of n-butyllithium, followed by deoxygenation of the double adducts with low-valent titanium. Both are bright red solids with a strong orange fluorescence in solution. The X-ray structures of these compounds show them to be the most highly twisted polycyclic aromatic hydrocarbons known. Compound 2 has an end-to-end twist of 144 degrees , and the two crystallographically independent molecules of 2m have twists of 138 degrees and 143 degrees. Both molecules were resolved by chromatography on chiral supports, and the pure enantiomers have extremely high specific rotations (for 2, [alpha]D = 7400 degrees; for 2m, 5600 degrees), but the molecules racemize slowly at room temperature (DeltaG++rac = 24 kcal/mol). Both the experimental geometry and the observed racemization barrier for 2 are in good agreement with computational studies of the molecule at a variety of levels. Attempts to prepare compound 2 by reaction of tetraphenylbenzyne with 9,10,12,13-tetraphenyl-11-oxacyclopenta[b]triphenylene (3, a twisted isobenzofuran) gave no adducts, and attempts to prepare tetradecaphenylpentacene by reaction of hexaphenylisobenzofuran (11) with bisaryne equivalents gave only monoadducts.


Asunto(s)
Antracenos/química , Antracenos/síntesis química , Hidrocarburos Policíclicos Aromáticos/química , Hidrocarburos Policíclicos Aromáticos/síntesis química , Simulación por Computador , Cristalografía por Rayos X , Modelos Moleculares , Estructura Molecular
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