Química
Envíos recientes
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Fungi with history: Unveiling the mycobiota of historic documents of Costa Rica
(2022-06-12)Through nondestructive techniques, we studied the physicochemical characteristics and mycobiota of five key historic documents from Costa Rica, including the Independence Act of Costa Rica from 1821. We determined that for ... -
Synthesis and Antibacterial Activity of Aromatic Homopropargyl Alcohols
(2017)Several aromatic homopropargyl alcohols, and derivatives were prepared by one-pot reaction of 1,3-dilithiopropyne (or its equivalent) with aldehydes and ketones. The antibacterial activity, of alcohols ... -
Palladium-Catalyzed One-Pot Conversion of Aldehydes and Ketones into 4‑Substituted Homopropargyl Alcohols and 5‑En-3-yn-1-ols
(2017)Sequential treatment of 2,3-dichloropropene with magnesium and n-BuLi generated the equivalent of 1,3- dilithiopropyne, which adds regiospecifically to aldehydes and ketones to produce homopropargyl alcohols. The ... -
Synthesis and Determination of Antibacterial Activity of Jacaranone and Synthetic Analogs
(2017)Natural product jacaranone, 1, and five more analog derivatives were synthesized and its antibacterial activity against Gram-positive and Gram-negative microorganisms was tested. One of these derivatives, 5, ... -
Uncovering the Cultivable Microbial Diversity of Costa Rican Beetles and Its Ability to Break Down Plant Cell Wall Components
(2014)Coleopterans are the most diverse insect order described to date. These organisms have acquired an array of survival mechanisms through their evolution, including highly efficient digestive systems. Therefore, the coleopteran ... -
Identification of Protein Kinase C Activation as a Novel Mechanism for RGS2 Protein Upregulation through Phenotypic Screening of Natural Product Extracts
(2014)Biochemical high-throughput screening is widely used in drug discovery, using a variety of small molecule libraries. However, broader screening strategies may be more beneficial to identify novel biologic mechanisms. In ... -
Identification of polyphenols from antiviral Chamaecrista nictitans extract using high-resolution LC–ESI–MS/MS
(2014)Chamaecrista nictitans (L) extract possesses antiviral properties; it acts against the herpes simplex virus, and this may be attributed to its constituent phenolics. Here, high-resolution LC–ESI–MS/MS is used to identify ... -
Baulamycins A and B, Broad-Spectrum Antibiotics Identified as Inhibitors of Siderophore Biosynthesis in Staphylococcus aureus and Bacillus anthracis
(2014)Siderophores are high-affinity iron chelators produced by microorganisms and frequently contribute to the virulence of human pathogens. Targeted inhibition of the biosynthesis of siderophores staphyloferrin B of Staphylococcus ... -
Isolation of Major Components from the Roots of Godmania aesculifolia and Determination of Their Antifungal Activities
(2013)From the methanol root extract of Godmania aesculifolia, a species selected in a multinational OAS program aimed at discovering antifungal compounds from Latin American plants, a new chavicol diglycoside (1), the known ... -
Identification of Anziaic Acid, a Lichen Depside from Hypotrachyna sp., as a New Topoisomerase Poison Inhibitor
(2013)Topoisomerase inhibitors are effective for antibacterial and anticancer therapy because they can lead to the accumulation of the intermediate DNA cleavage complex formed by the topoisomerase enzymes, which trigger cell ... -
Sekikaic Acid and Lobaric Acid Target a Dynamic Interface of the Coactivator CBP/p300
(2012-10-08)Although there have been recent notable successes in thediscovery of ligands that target stable, high-affinity protein-protein interactions (PPIs), the transient and moderateaffinity PPIs that underpin many fundamental ... -
Phenolic compounds as antiangiogenic CMG2 inhibitors from costa rican endophytic fungi
(2012)Targeting and inhibiting CMG2 (Capillary Morphogenesis Gene protein 2) represents a new strategy for therapeutic agents for cancer and retinal diseases due to CMG2’s role in blood vessel growth (angiogenesis). A high ... -
A New Method for the Preparation of 1-Ethynyl Ethers
(1994)During our study of the stannylcupration of acetylenic ethers we required [2-13C]-1 for mechanistic studies. Existing methods for the synthesis of acetylenic ethers involve dehydrohalogenation of 2-halo, ... -
An Improved stereospecific synthesis of (Z,E)-tetradecadienal. Sex pheromone component of Stenoma cecropia
(1998)(Z,E)-9, 11-Tetradecadienal, a sex pheromone component of Stenoma cecropia, has been synthesized in 7 steps and 61% overall yield. The synthesis utilized a palladium catalyzed coupling between 9-decynyl tert-butyldinethylsilyl ... -
Una nueva ruta para la sintesis de la feromona sexual de la polilla de la papa, Scrobipalpopsis solanivora
(1996)Acetato de (E)-3-dodecenilo, principal componente de feromona de Scrobipal-popsis solanivora, se preparó con un rendimiento total del 61 %. El precursor, 3-dodecin-1-ol, se preparó en el paso de un recipiente mediante la ... -
An improved stereospecific synthesis of (Z,E)-9, 11, 13-Tetradecatrienal. Sex pheromone component of Stenoma cecropia
(2000)(Z,E)-9,11,13-tetradecatrienal, a pheromone component of Stenoma cecropia, was prepared in 61% overall yield from 1-nonyne. The synthesis involved two palladium-catalyzed cros-couplings to afford a 1,3-dien5-yne, which was ... -
A new method for the preparation of 1,3-dilithiopropyne: an efficient synthesis of homopropargyl alcohols
(2001)Controlled dilithiation of propargyl bromide with two equivalents of n-butyllithium, in the presence of TMEDA, produces the operational equivalent of the dianion 1,3-dilithiopropyne. The latter reacts efficiently with ... -
Organic Carbon Determination by the Walkley-Black and Dry Combustion Methods in SurfaceSoils and Andept Profiles from Costa Rica
(1979-01)The efficiency of oxidation of organic C by the Walkley-Black method was studied by comparing with determinations using dry combustion equipment and gravimetric determination for the evolved CO2. Fifty surface soils (0-30 ... -
Estudio sobre cambios fisico-químicos durante la fermentación del pasto elefante en microsilos de laboratorio con tres niveles de melaza
(1981)Physical and chemical changes during the fermentation of elephant grass with three levels of sugar cane molasses, in laboratory silos. The effect of the adition of sugar cane molasses on the chemical composition and nutritive ... -
Fate of buturon-14C in soil during seven seasons of exposure under outdoor conditions
(1984-03)Buturon (ring 14C) was applied to wheat and soil in two successive years (3 kg/ha each year) at outdoor conditions. Residual radioactive substances in the upper soil layer (0-10-cm depth) were measured 1.5, 2.5, 3.5, 6.0, ...
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