Enantiopure 4‐oxazolin‐2‐ones and 4‐methylene‐2‐oxazolidinones as chiral building blocks in a divergent asymmetric synthesis of heterocycles

En este trabajo se describe la reactividad de las oxazolidin-2-onas en un ambiente quiral obteniéndose resultados novedosos, los cuales se describen extensamente.Enantiopure 3‐((R)‐ and 3‐((S)‐1‐phenylethyl)‐4‐oxazoline‐2‐ones were evaluated as chiral building blocks for the divergent construction of heterocycles with stereogenic quaternary centers. The N‐(R)‐ or N‐(S)‐1‐phenylethyl group of these compounds proved to be an efficient chiral auxiliary for the asymmetric induction of the 4‐ and 5‐positions of the 4‐oxazolin‐2‐one ring through thermal and MW‐promoted nucleophilic conjugated addition to Michael acceptors and alkyl halides. The resulting adducts were transformed via a cascade process into fused six‐membered carbo‐ and heterocycles. The structure of the reaction products depended on the electrophiles and reaction conditions used. Alternative isomeric 4‐methylene‐2‐oxazolidinones served as chiral precursors for a versatile and divergent approach to highly substituted cyclic carbamates. DFT quantum calculations showed that the formation of bicyclic pyranyl compounds was generated by a diastereoselective concerted hetero‐Diels‐Alder cycloaddition.Instituto Politécnico Nacional, Secretaria de Investigación y Estudios Avanzados de la Universidad Autónoma del Estado de México, Universidad de Guanajuato y CONACYT

Identification of virulence factors genes in Escherichia coli isolates from women with urinary tract infection

E coli isolates (108) from Mexican women, clinically diagnosed with urinary tract infection, were screened to identify virulence genes, phylogenetic groups, and antibiotic resistance. Isolates were identified by MicroScan4 system; additionally, the minimum inhibitory concentration (MIC) was assessed. The phylogenetic groups and 16 virulence genes encoding adhesins, toxins, siderophores, lipopolysaccharide (LPS), and invasins were identified by PCR. Phylogenetic groups distribution was as follows: B1 9.3%, A 30.6%, B2 55.6%, and D 4.6%. Virulence genes prevalence was ecp 98.1%, fimH 86.1%, traT 77.8%, sfa/focDE 74.1%, papC 62%, iutA 48.1%, fyuA 44.4%, focG 2.8%, sfaS 1.9%, hlyA 7.4%, cnf-1 6.5%, cdt-B 0.9%, cvaC 2.8%, ibeA 2.8%, and rfc 0.9%. Regarding antimicrobial resistance it was above 50% to ampicillin/sulbactam, ampicillin, piperacillin, trimethoprim/sulfamethoxazole, ciprofloxacin, and levofloxacin. Uropathogenic E. coli clustered mainly in the pathogenic phylogenetic group B2. The isolates showed a high presence of siderophores and adhesion genes and a low presence of genes encoding toxins. The high frequency of papC gene suggests that these isolates have the ability to colonize the kidneys. High resistance to drugs considered as first choice treatment such as trimethoprim/sulfamethoxazole and fluoroquinolones was consistently observed

La Avifauna de la región de las Altas Montañas de Veracruz, México

Objective: In the region, no formal studies are systematizing the total richness of bird species, the data here presented has been generated by the authors though several observation initiatives; as well as publications and materials for its diffusion. The main objective is to announce the ornithological richness, an overview of its situation, the activities carried out to encourage its knowledge, conservation, and the troubles faced Design/methodology/approach: A bibliographic review, observations, and auditive records of birds were conducted in situ, following Ralph et al. techniques in the nine types of vegetation encompassed in the region, added with the revision of National Collection of Birds from UNAM and CONABIO databases. Results: We report 515 bird species, 119 are under risk, 79% were in situ records, and 21% from additional sources. 50 species have some endemism status, 14 have shown expansion in their distribution, 65.2% are residents and 34.8% have some migrant status. Finally, eight different problems affecting birds are here reported. Limitations on study/implications: Have no in situ records of birds in 12 municipalities of the region due to a scarce relationship with authorities and lack of budget Findings/conclusions: The ornithological richness encompassing here holds 71.6% of the state. It is necessary to expand the monitoring effort in 12 municipalities where there are no bird data records. The region is ideal for avitourism, especially as it has the widest altitude gradient, not only in Mexico but in North and Central America.Objetivo: En la región de las Altas Montañas de Veracruz no existen estudios formales que sistematicen la riqueza total de especies de aves, a pesar de que en ella se ubican Áreas de Importancia para la Conservación de las Aves y Áreas Naturales Protegidas (federales y estatales); en la región se cuenta con una red de monitoreo comunitario de aves y los autores recientemente han originado diversas publicaciones y materiales para la difusión de la avifauna de la región. El objetivo principal es dar a conocer la riqueza ornitológica de la región, un panorama de su situación y su problemática, así como las actividades que se están realizando para impulsar su conocimiento y conservación. Diseño/metodología/aproximación: Se llevó a cabo una revisión bibliográfica, observaciones y registros auditivos de aves in situ siguiendo la técnica de búsqueda intensiva de Ralph et al., en los nueve tipos de vegetación presentes en la región, así como también se revisó la base de datos de CONABIO-AVER-AVES y la Colección Nacional de Aves de la UNAM. Resultados: Se obtuvo una riqueza de 514 especies, de las cuales, el 79% fueron especies registradas in situ y el 21% de otras fuentes; 50 especies presentan algún estatus de endemismo, 14 muestran ampliación en su distribución, así como también se reportan ocho diferentes problemáticas que afectan a las aves. El 65.2% de las especies registradas se consideran residentes y el 34.8% muestran algún estatus de migración. Del total de especies, 119 se encuentran en alguna lista de especies en riesgo. Limitaciones del estudio/implicaciones: El no contar con registros in situ de 12 de los municipios debido a la poca relación con las autoridades y la falta de presupuesto. Conclusiones: La riqueza ornitológica de la región de las Altas Montañas abarca el 71.6% de las especies registradas para el estado de Veracruz. Los resultados indican que se debe ampliar el esfuerzo de monitoreo en 12 de 57 municipios de la región, donde no se tienen registros de datos ornitológicos, es decir, siguen inexplorados desde el punto de visto ornitológico. Por otra parte, tomando en cuenta esta gran riqueza de aves, la región tiene un alto potencial para el aviturismo, dado el amplio gradiente altitudinal que presenta, uno de los más amplios, no solo de México, sino de Norte y Centroamérica

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum