Phenylenevinylene Systems: The Oligomer Approach

Among conducting polymers, poly-p-phenylenevinylenes (PPVs) have attained a special place in polymer electronics. The optoelectronic properties initially exposed by PPVs in organic light-emitting diodes (OLEDs) turned these organic electronic conjugated systems from the solo academic interest into a technologically very promising area. The easiness of the tuning of their optoelectronic properties through synthetic modifications make PPVs an outstanding and suitable compound for technological applications and fundamental science development. Unfortunately, the synthesis and structural optoelectronic characterization of novel PPVs is a long and difficult task that sometimes yields unclear results. However, phenylenevinylene oligomers (oPV) can be synthesized and characterized in a very straightforward manner, and their performance in novel applications can be directly related to their structural analogue polymer, methodology designated as the oligomer approach. Herein, we describe the oligomer approach using the Mizoroki-Heck reaction as a synthetic route for oPVs and PPVs, and the importance of an extensive characterization for novel applications, such as photocatalysis and matrix-assisted laser desorption/ionization (MALDI) matrices, where these electronic conjugated systems have very promising applications

TRANSFORMACIÓN QUÍMICA DE LOS 4-N-BENCIL ( α-FENILETIL)AMINO-4-PIRIDIL-1-BUTENOS

An easy and simple synthetic route allowed the homoalylamines oxidation and its later conversion. New derived benzamides of the pyiridine was obtained. The basic hydrolisis of these amides produced new primary amines that can be employees as precursors of biologically active substance

Síntesis de terpiridinas 4-fenil sustituídas y su potencial uso en la determinación de mercurio

En este trabajo se reporta la síntesisde terpiridinas bajo la metodología deKröhnke. Las terpiridinas obtenidas poreste método, se analizaron por espectroscopiaUV-Vis y de fluorescencia, y surespuesta a la presencia de varios metalesen diferentes concentraciones fue evaluadapara sistemas en solución acuosa. Losresultados muestran que la terpiridinaTpyOH es altamente promisoria en la detecciónde mercurio bajo las condicionesexperimentales reportadas

Sistemas fenilenvinileno-terpiridina como quimiosensores de mercurio en agua

Spa: Se sintetizaron tres sistemas fenilenvinileno-terpiridina (FV-Tpy) mediante la reacción de acoplamiento carbono-carbono de Heck, los cuales se caracterizaron mediante espectroscopía de infrarrojo, resonancia magnética nuclear protónica-carbono 13 y espectrometría de masas. Se determinaron sus propiedades fisicoquímicas, tales como; coeficiente de absortividad molar y rendimiento cuántico de fluorescencia, mostrando que presentan características optoelectrónicas que los hacen atractivos sistemas para construir quimiosensores fluorescentes. Por lo tanto, se realizaron ensayos de selectividad y sensibilidad frente a cationes presentes en fuentes hídricas cercanas a sitios de explotación minera Colombiana, entre los cuales están; Pb, Cd, Zn y Hg. Se encontró que los sistemas FV-Tpy pueden ser altamente selectivos hacia mercurio en concentraciones tan bajas como 10 ppb según la naturaleza química del sustituyente unido directamente al sistema electrónicamente conjugado. Mostrando que los sistemas FV-Tpy sufren desde quenching de la fluorescencia hasta corrimientos hacia la región azul del espectro visible cuando coordinan al Hg

Synthesis, characterization, X-ray crystal structure and DFT calculations of 4-([2,2':6',2''-terpyridin]- 4'-yl)phenol

The synthesis of new terpyridine (Tpy) derivatives has been subject of extensive research due to its potential as functional materials for solar energy conversion, among other applications. In this contribution, the 4-([2,2':6',2''-terpyridin]-4'-yl)phenol (TpyOH) has been synthesized, characterized and studied through several methods, including X-ray crystallography and computational approaches. Single crystal X-ray structure analysis shows that TpyOH is essentially planar, with dihedral angles of about 5.03° between the central pyridinyl and the phenolic ring, and also 6.05 and 12.2° in the terpyridine moiety. In the crystal, molecules arelinked by intermolecular hydrogen bonds and through π-π stacking interactions. Using a time-dependent density functional theory approach and taking into account bulk solvent effects, the absorption and fluorescence spectra of TpyOH were investigated and compared. The TD-DFT S0→Sn and S1→S0 transition energies are in good agreement with experimental results. The frontier molecular orbitals analysis showed that the low-energy absorption band has anintraligand charge transfer character (ICT), while the high-energy band is a common feature of π-π* transitions of the Tpy moiety. The S1→S0 emission transition also has an ICT character, with a 90% contribution from the HOMO→LUMO transitions.A síntese de derivados de terpiridina (Tpy) tem sido estudada devido ao seu potencial para a conversão de energia solar. Nesta contribuição, o 4-([2,2':6',2''- terpiridina]-4'-il) fenol (TpyOH) foi sintetizado, caracterizado e estudado por vários métodos. A análise de estrutura de raios X de cristal único mostra que o TpyOH é plano, com ângulos diedros de 5,03 ° entre o piridinilo central e o anel fenólico, e também 6,05 e 12,2 ° na porção de terpiridina. No cristal, as moléculas são ligadas por ligações intermoleculares de hidrogênio e através de interações de empilhamento π-π. Usando uma abordagem da teoria funcional da densidade dependente do tempo e levando em consideração os efeitos do solvente em massa, foram investigados e comparados os espectros de absorção e fluorescência do TpyOH. As energias de transição TD-DFT S0→Sn e S1→S0 estão de acordo com os resultados experimentais. A análise de orbitários moleculares de fronteira mostrou que a banda de absorção de baixa energia possui um caráter de transferência de carga intraligando (TIC), enquanto a banda de alta energia é uma característica comum das transições π-π* da fração Tpy. A transição de emissão S1→S0 também tem um caráter TIC, com uma contribuição de 90% das transições HOMO→LUMO.La síntesis de derivados terpiridinicos (Tpy) se ha investigado ampliamente debido a su potencial para la conversión de  energía solar. En este artículo se sintetizó  y caracterizó el 4-([2,2':6',2'' terpiridin]-4'-il)fenol (TpyOH), a través de varias metodologías como la cristalografía de rayos X y herramientas computacionales. El análisis de rayos X de monocristal mostró que el TpyOH es plano, con ángulos diedros de 5,03° entre el piridinilo central y el anillo fenólico, con presencia de ángulos de 6,05 y 12,2º en la porción terpiridínica. En el cristal, las moléculas están unidas por  enlaces  de  hidrógeno intermoleculares  y  mediante  interacciones  de apilamiento  π-π. Utilizando cálculos DFT dependientes del tiempo (TD-DFT) y teniendo en cuenta el efecto de los  disolventes, se investigaron y  compararon los  espectros  de absorción  y fluorescencia  de TpyOH. Las energías de transición TD-DFT de S0→Sn y S1→S0 concuerdan con los resultados experimentales. El análisis de orbitales moleculares de frontera mostró que la banda de absorción de baja energía corresponde a transferencia de carga intraligando (ICT); mientras que la banda de alta energía es común en las transiciones π-π* del resto Tpy. La emisión debido a la transición S1→S0 corresponde  a  ICT,  con  una  contribución  del 90%  proveniente  de  transiciones HOMO→LUMO

Congreso Internacional de Responsabilidad Social Apuestas para el desarrollo regional.

Congreso Internacional de Responsabilidad Social: apuestas para el desarrollo regional [Edición 1 / Nov. 6 - 7: 2019 Bogotá D.C.]El Congreso Internacional de Responsabilidad Social “Apuestas para el Desarrollo Regional”, se llevó a cabo los días 6 y 7 de noviembre de 2019 en la ciudad de Bogotá D.C. como un evento académico e investigativo liderado por la Corporación Universitaria Minuto de Dios -UNIMINUTO – Rectoría Cundinamarca cuya pretensión fue el fomento de nuevos paradigmas, la divulgación de conocimiento renovado en torno a la Responsabilidad Social; finalidad adoptada institucionalmente como postura ética y política que impacta la docencia, la investigación y la proyección social, y cuyo propósito central es la promoción de una “sensibilización consciente y crítica ante las situaciones problemáticas, tanto de las comunidades como del país, al igual que la adquisición de unas competencias orientadas a la promoción y al compromiso con el desarrollo humano y social integral”. (UNIMINUTO, 2014). Dicha postura, de conciencia crítica y sensibilización social, sumada a la experiencia adquirida mediante el trabajo articulado con otras instituciones de índole académico y de forma directa con las comunidades, permitió establecer como objetivo central del evento la reflexión de los diferentes grupos de interés, la gestión de sus impactos como elementos puntuales que contribuyeron en la audiencia a la toma de conciencia frente al papel que se debe asumir a favor de la responsabilidad social como aporte seguro al desarrollo regional y a su vez al fortalecimiento de los Objetivos de Desarrollo Sostenible

Congreso Internacional de Responsabilidad Social Apuestas para el desarrollo regional.

Congreso Internacional de Responsabilidad Social: apuestas para el desarrollo regional [Edición 1 / Nov. 6 - 7: 2019 Bogotá D.C.]El Congreso Internacional de Responsabilidad Social “Apuestas para el Desarrollo Regional”, se llevó a cabo los días 6 y 7 de noviembre de 2019 en la ciudad de Bogotá D.C. como un evento académico e investigativo liderado por la Corporación Universitaria Minuto de Dios -UNIMINUTO – Rectoría Cundinamarca cuya pretensión fue el fomento de nuevos paradigmas, la divulgación de conocimiento renovado en torno a la Responsabilidad Social; finalidad adoptada institucionalmente como postura ética y política que impacta la docencia, la investigación y la proyección social, y cuyo propósito central es la promoción de una “sensibilización consciente y crítica ante las situaciones problemáticas, tanto de las comunidades como del país, al igual que la adquisición de unas competencias orientadas a la promoción y al compromiso con el desarrollo humano y social integral”. (UNIMINUTO, 2014). Dicha postura, de conciencia crítica y sensibilización social, sumada a la experiencia adquirida mediante el trabajo articulado con otras instituciones de índole académico y de forma directa con las comunidades, permitió establecer como objetivo central del evento la reflexión de los diferentes grupos de interés, la gestión de sus impactos como elementos puntuales que contribuyeron en la audiencia a la toma de conciencia frente al papel que se debe asumir a favor de la responsabilidad social como aporte seguro al desarrollo regional y a su vez al fortalecimiento de los Objetivos de Desarrollo Sostenible

Potent and selective ABCG2 inhibitors derived from tariquidar

Three different classes of selective ABCG2 modulator (BCRP, breast cancer resistance protein) derived from the lead structure tariquidar have been prepared in this thesis. In chapters one and two the solid phase synthesis approach was used to obtain new derivatives of the lead structure and two different methodologies were developed. A very simple, effective and straightforward method of synthesis using Wang resing as solid support was developed in chapter one. A small library of new tariquidar derivatives was obtained in very good yields, improving thus the solution synthesis previously reported. Some of the new compounds bearing a triethylenglycol chain at the tetrahydroisoquinoline core proved to be better soluble in comparison to the other analogs. The inhibitory activity against ABCB1 and ABCG2 transporters were evaluated for all the compounds synthesized. During this work it was discovered that the methyl esters bearing both, a triethylene glycol ether and a quinoline-2-carboxamido substituent, showed selectivity for ABCG2 over ABCB1 and are superior compared to the lead structure with respect to the maximal inhibitory effect. These compounds are among the most potent and selective ABCG2 modulators reported so far and might be useful to reverse the multidrug phenomenon in cancer cells. The second chapter, in which Wang resing was also used as solid support, describes a methodology more elaborated for the synthesis of new tariquidar-like derivatives. In order to obtain more stable compounds, the amide bond between the amino anthranilic ring and the tetrahydroisoquinolinethylphenylamine moiety was replaced and the two fragments of the molecule were linked by a C-C bond using Suzuki coupling. A set of eight compounds were obtained using the solid phase methodology, and four compounds were synthesized in solution. ABCB1 and ABCG2 inhibitory activity of the analogues were determined in the calcein-AM and the Hoechst 33342 microplate assay, respectively, and its result showed that all tested compounds are selective to ABCG2. The most potent compound in this series has an IC50 value of 591± 87 nM, and Imax 109% relative to FTC. Stability test, performed in mouse plasma, revealed that the enzymatic degradation of this derivative starts after 30 min, but after 24 h, around 60% of the compound still remains intact. The structural characteristics of the compounds here obtained together with their activity may contribute to design a new class of active and more stable tariquidar derivatives. The last chapter describes the synthesis of another class of ABCG2 inhibitors bearing an indole core unit. The modifications were done to overcome stability problems and to improve the solubility of the compounds. In the new compounds, that share structural characteristics of the best inhibitors previously synthesized, an indole fragment was introduced as central core in order to increase the stability of the compound. The indole fragment was synthesized by a Sonogashira coupling followed by palladium catalyzed cyclization to the heterocycle. The mesyl group at the nitrogen of the indole was removed and the selectivity and inhibitory activity of the compounds for ABCG2 was determined. The most potent and promising compound has a lower IC50 value (59 ± 14 nM) and a very close maximal inhibitory effect (Imax 100%) compared to the most potent and selective ABCG2 reported so far Ko143, (117 ± 53 nM, Imax 103 ± 7%). The selectivity, the increased activity and the biological stability of some analogues render these compounds good candidates for in vivo studies in order to overcome drug resistance of tumor cells associated to ABCG2 transporters

9-(4-Hydroxybutyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione

The title compound 9-(4-hydroxybutyl)-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione was synthesized in 72% yield through a simple, convenient and environmentally friendly one-pot reaction between dimedone and 3,4-dihydro-2H-pyran in aqueous citric acid. Additionally, a plausible reaction mechanism for the formation of the target xanthene is proposed

1,4-Di(2-butoxycarbonyl-trans-vinyl)-2,5-dimethoxybenzene

The title compound 1,4-di(2-butoxycarbonyl-trans-vinyl)-2,5-dimethoxybenzene was synthesized in 94% yield through the Heck reaction between 2,5-diiodo-1,4-dimethoxybenzene and n-butyl acrylate, using bis(dibenzylideneacetone) palladium(0) as homogeneous catalyst