Browsing by Author "Marquez, Edgar"

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    Changes in Protonation Sites of 3-Styryl Derivatives of 7-(dialkylamino)-aza-coumarin Dyes Induced by Cucurbit[7]uril
    (2022) Alcazar, Jackson J.; Marquez, Edgar; Garcia-Rio, Luis; Robles-Munoz, Agustin; Fierro, Angelica; Santos, Jose G.; Aliaga, Margarita E.
    The incorporation of a guest, with different basic sites, into an organized system (host), such as macrocycles, could stabilize, detect, or promote the formation of a certain protomer. In this context, this work aimed to study the influence of cucurbit[7]uril (CB7) on dyes such as 7-(dimethylamino)-aza-coumarins, which have more than one basic site along their molecular structure. For this, three 3-styryl derivatives of 7-(dialkylamino)-aza-coumarin dyes (SAC1-3) were synthesized and characterized by NMR, ESI-HRMS and IR. The spectral behaviour of the SACs in the absence and presence of CB7 was studied. The results showed large shifts in the UV-vis spectrum in acid medium: a hypsochromic shift of approximate to 5400 cm(-1) (SAC1-2) and approximate to 3500 cm(-1) (SAC3) in the absence of CB7 and a bathochromic shift of approximate to 4500 cm(-1) (SAC1-3) in the presence of CB7. The new absorptions at long and short wavelengths were assigned to the corresponding protomers by computational calculations at the density functional theory (DFT) level. Additionally, the binding mode was corroborated by molecular dynamics simulations. Findings revealed that in the presence of CB7 the heterocyclic nitrogen was preferably protonated instead of the dialkylamino group. Namely, CB7 induces a change in the protonation preference at the basic sites of the SACs, as consequence of the molecular recognition by the macrocycle.
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    Classical QSAR and Docking Simulation of 4-Pyridone Derivatives for Their Antimalarial Activity
    (2018) Flores-Sumoza, Maryury; Alcázar Jiménez, Jackson José; Marquez, Edgar; Mora, Jose R.; Lezama, Jesus; Puello, Esneyder
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    Predicting the Adsorption of Amoxicillin and Ibuprofen on Chitosan and Graphene Oxide Materials: A Density Functional Theory Study
    (2021) Anchique, Leonardo; Alcazar, Jackson J.; Ramos-Hernandez, Andrea; Mendez-Lopez, Maximiliano; Mora, Jose R.; Rangel, Norma; Luis Paz, Jose; Marquez, Edgar
    The occurrence, persistence, and accumulation of antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) represent a new environmental problem due to their harmful effects on human and aquatic life. A suitable absorbent for a particular type of pollutant does not necessarily absorb other types of compounds, so knowing the compatibility between a particular pollutant and a potential absorbent before experimentation seems to be fundamental. In this work, the molecular interactions between some pharmaceuticals (amoxicillin, ibuprofen, and tetracycline derivatives) with two potential absorbers, chitosan and graphene oxide models (pyrene, GO-1, and coronene, GO-2), were studied using the omega B97X-D/6-311G(2d,p) level of theory. The energetic interaction order found was amoxicillin/chitosan > amoxicillin/GO-1 > amoxicillin/GO-2 > ibuprofen/chitosan > ibuprofen/GO-2 > ibuprofen/GO-1, the negative sign for the interaction energy in all complex formations confirms good compatibility, while the size of E-int between 24-34 kcal/mol indicates physisorption processes. Moreover, the free energies of complex formation were negative, confirming the spontaneity of the processes. The larger interaction of amoxicillin Gos, compared to ibuprofen Gos, is consistent with previously reported experimental results, demonstrating the exceptional predictability of these methods. The second-order perturbation theory analysis shows that the amoxicillin complexes are mainly driven by hydrogen bonds, while van der Waals interactions with chitosan and hydrophobic interactions with graphene oxides are modelled for the ibuprofen complexes. Energy decomposition analysis (EDA) shows that electrostatic energy is a major contributor to the stabilization energy in all cases. The results obtained in this work promote the use of graphene oxides and chitosan as potential adsorbents for the removal of these emerging pollutants from water.
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    Synthesis, Photophysical Properties, Theoretical Studies, and Living Cancer Cell Imaging Applications of New 7-(Diethylamino)quinolone Chalcones
    (2024) Insuasty, Daniel; Mutis, Mario; Trilleras, Jorge; Illicachi, Luis A.; Rodriguez, Juan D.; Ramos-Hernandez, Andrea; San-Juan-Vergara, Homero G.; Cadena-Cruz, Christian; Mora, Jose R.; Paz, Jose L.; Mendez-Lopez, Maximiliano; Perez, Edwin G.; Aliaga, Margarita E.; Valencia, Jhesua; Marquez, Edgar
    In this article, three unsymmetrical 7-(diethylamino)quinolone chalcones with D-pi-A-D and D-pi-A-pi-D type push-pull molecular arrangements were synthesized via a Claisen-Schmidt reaction. Using 7-(diethylamino)quinolone and vanillin as electron donor (D) moieties, these were linked together through the alpha,beta-unsaturated carbonyl system acting as a linker and an electron acceptor (A). The photophysical properties were studied, revealing significant Stokes shifts and strong solvatofluorochromism caused by the ICT and TICT behavior produced by the push-pull effect. Moreover, quenching caused by the population of the TICT state in THF-H2O mixtures was observed, and the emission in the solid state evidenced a red shift compared to the emission in solution. These findings were corroborated by density functional theory (DFT) calculations employing the wb97xd/6-311G(d,p) method. The cytotoxic activity of the synthesized compounds was assessed on BHK-21, PC3, and LNCaP cell lines, revealing moderate activity across all compounds. Notably, compound 5b exhibited the highest activity against LNCaP cells, with an LC50 value of 10.89 mu M. Furthermore, the compounds were evaluated for their potential as imaging agents in living prostate cells. The results demonstrated their favorable cell permeability and strong emission at 488 nm, positioning them as promising candidates for cancer cell imaging applications.
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    Theoretical Calculations of the Multistep Reaction Mechanism Involved in Asparagine Pyrolysis Supported by Degree of Rate Control and Thermodynamic Control Analyses
    (2019) Cervantes, Cristian; Mora, Jose R.; Marquez, Edgar; Torres, Javier; Rincon, Luis; Mendez, Miguel A.; Alcazar, Jackson J.
    A computational study on the mechanisms of reaction for the pyrolysis of asparagine is presented. A density functional theory (DFT) study at the omega B97XD/6-311G(d,p) level was performed to analyze the differences in two reaction mechanisms: (i) the formation of five-membered cyclic products: maleimide and succinimide, and (ii) the more classical, six-membered cyclic products (diketopiperazine species) which are common in the pyrolysis of many other amino acids. The effect of temperature was included in the calculations at 300 degrees C or 625 degrees C, as required. Moreover, a detailed study based on the degree of rate control and thermodynamic control of the proposed mechanism for the formation of maleimide and succinimide is also presented. Results show that, for asparagine, the five-membered ring formation is the preferred process instead of the six-membered cycle (32 kJ/mol of Gibbs free energy difference between them at the first cyclization step); therefore, the polymerization is favored. On the other hand, the rupture of the polymer represents the highest energetic barrier (Delta G(double dagger) = 281 kJ/mol) and the most influential process in the overall rate of the reaction. These results are in good agreement with the experimental evidence.