Archivo de la categoría: 2014

Abarca et al. Org Lett. 2014;16(13):3464-7. Efficient synthesis of an indoloquinolizinium alkaloid selective DNA-binder by ring-closing metathesis.

Publicaciones > Abarca et al

Efficient synthesis of an indoloquinolizinium alkaloid selective DNA-binder by ring-closing metathesis.

Departamento de Quimica Organica y Quimica Inorganica, double daggerDepartamento de Biologia de Sistemas, section signDepartamento de Quimica Analitica, Quimica Fisica e Ingenieria Quimica, Universidad de Alcala , 28871-Alcala de Henares, Madrid, Spain.

Abstract

Two total syntheses of the indolo[2,3-a]quinolizinium cation have been accomplished through the application of two ring-closing metathesis reactions to form the pyridinium ring. One of these approaches provides the tetracyclic cation in only five steps from commercially available harmane. Fluorescence-based thermal denaturation experiments, as well as spectrofluorimetric titration, circular dichroism measurements, and theoretical simulations, showed a consistent DNA-binding capacity by intercalation with a marked preference for AT-rich sequences.

Sanchez et al. Org Biomol Chem. 2014;12(24):4233-42. Microwave-assisted synthesis of potent PDE7 inhibitors containing a thienopyrimidin-4-amine scaffold.

Publicaciones > Sanchez et al

Microwave-assisted synthesis of potent PDE7 inhibitors containing a thienopyrimidin-4-amine scaffold.

Departamento de Quimica Organica, Universidad de Alcala, E-28871 Alcala de Henares, Madrid, Spain. julio.alvarez.@uah.es.

Abstract

A series of novel thienopyrimidin-4-amines have been synthesized and evaluated as phosphodiesterase (PDE) inhibitors. A rationale for the observed selectivity against PDE7 has been obtained from molecular modelling studies on the most active compounds.

Carmona et al. Dyes and Pigments. 2014;:106-117. Cucurbit[n]urils as a potential fine-tuned instrument for modifying photophysical properties of D–π–A+–π–D “push–pull” chromophores.

Publicaciones > Carmona et al

Cucurbit[n]urils as a potential fine-tuned instrument for modifying photophysical properties of D–π–A+–π–D “push–pull” chromophores.

1. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.  2. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.

Abstract

Photophysical properties of supramolecular complexes between cucurbit[7]uril (CB[7]) and one- (1D, linear) and two-dimensional (2D, V-shaped) D–π–A+–π–D pyridinium (A+) based “push–pull” chromophores, were investigated by UV–Vis and fluorescence techniques, as well as Molecular Mechanics and Molecular Dynamics simulations. Both chromophores formed stable complexes with CB[7] of different stoichiometries. Complexation was accompanied by significant changes in the photophysical properties of the guests: (i) bathochromic shifts for the π–π* charge transfer absorption band, which is more evident for the 1D than for the V-shaped one, (ii) significant enhancement of the fluorescence intensity, (iii) displacement to the blue of the emission and (iv) change in their fluorescence lifetimes, which is more patent for the V-shaped one. 1D chromophore/CB[7] complex formation was both enthalpically and entropically favored, whereas inclusion of the V-shaped one, accompanied by a little positive enthalpy change, was entropically governed. Variation of fluorescence lifetime and fluorescence anisotropy upon complexation exhibited quite different behaviors. MM and MD calculations were performed to simulate the complexation processes in the presence of water, determine their preferred structures and establish the host:guest interactions responsible for the complexes formation which were preferentially electrostatics.

Cañeque et al. Dyes and Pigments. 2014;:116-121. Novel charged NLO chromophores based on quinolizinium acceptor units.

Publicaciones > Cañeque et al

Novel charged NLO chromophores based on quinolizinium acceptor units.

1. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.  2. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  3. Department of Chemistry, University of Leuven, Celestijnenlaan 200 D, B-3001, Belgium.  4. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.  5. IES Matarraña, 44580 Valderrobres, Teruel, Spain.

Abstract

An azonia cation has been explored for the first time as an acceptor unit in charged π-donor π-acceptor chromophores. Initial experimental and theoretical data show that quinolizinium, the simplest heteroaromatic azonia cation, behaved as a good acceptor unit and conferred promising nonlinear optical properties to simple push–pull cationic chromophores.