Browsing Química by Title
Now showing items 194-213 of 322
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N-[3-(Prop-1-yn-1-yl)phenyl]benzenesulfonamide
(2019)In the title sulfanilamide derivative, C15H13NO2S, which shows significant activity against Staphylococcus aureus and Escherichia coli, the dihedral angle between the planes of the aromatic rings is 62.15 (19)° and the ... -
Naphthalenones and Isocoumarins from a Costa Rican Fungus Xylariaceae sp. CR1546C
(2014)A new naphthalenone, (R)-4,6,8-trihydroxy-3,4-dihydro-1(2H)-naphthalenone and a new isocoumarin, 6,8-dihydroxy-(3R)-(2-oxopropyl)-3,4-dihydroisocoumarin, together with eight related known compounds were isolated from the ... -
Natural product based inhibitors of the thioredoxin-thioredoxin reductase system
(2004)Spiroketal naphthodecalins are readily assembled by Barton's base mediated Ullmann binaphthyl ether coupling, Dakin reactions and hypervalent iodine spirocyclization. The core structures can be further diversified by enone ... -
Neutral organic redox pairs based on sterically hindered hydroquinone/benzoquinone derivatives for dye-sensitized solar cells
(2018-06)Substituted derivatives of hydroquinone/benzoquinone were studied as organic redox mediators in the electrolyte for dye-sensitized solar cells (DSSCs). Thus, di-tert-butylhydroquinone (DTHQ), thymohydroquinone (ThymHQ) and ... -
Nickel-iron catalysts for electrochemical water oxidation – redox synergism investigated by in situ X-ray spectroscopy with millisecond time resolution
(2018)In future technological systems for chemical storage of renewable energy and production of non-fossil fuels, NiFe oxyhydroxides are prime candidates for efficient alkaline water oxidation (oxygen evolution reaction, OER). ... -
Norstictic Acid Is a Selective Allosteric Transcriptional Regulator
(2021-06-17)Inhibitors of transcriptional protein–protein interactions (PPIs) have high value both as tools and for therapeutic applications. The PPI network mediated by the transcriptional coactivator Med25, for example, regulates ... -
Nota sobre la Preparación de un Dicatión Cuaternario de Azufre Divalente
(1979)A synthesis has been developed for the previously unreported salts of S,S-di-(1-methylbenzimidazol-2-yl)-S,S-dimethylsulfonium dication [3] derived from the sulfide [2] and dimethyl-sulfate. -
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 ... -
Nueva síntesis de la feromona sexual de la polilla del repollo Plutella Xylostella
(2007)El compuesto (Z)-11-hexadecenal, feromona sexual de la polilla Plutella xylostella, fue preparado mediante tres secuencias sintéticas. La primer secuencia consistió de siete pasos y un rendimiento total de 47%. En las otras ... -
Nuevos métodos de preparación del 1,3-Dilitiopropino y sus aplicaciones en la síntesis de compuestos bioactivos
(2006)Se desarrolló un método para la preparación del 1,3-dilitiopropino, a partir de bromuro de propargilo. Este procedimiento ha sido usado para desarrollar nuevos métodos de síntesis de alcoholes homopropargílicos, 1,5-diinos, ... -
One-Pot Conversion of Aldehydes and Ketones into 1-Substituted and 1,4-Disubstituted 1,3-Enynes
(2018)Sequential treatment of 2,3-dichloropropene with magnesium and n-BuLi generates the operational equivalent of 1,3-dilithiopropyne, which upon treatment with aldehydes or ketones, produces the corresponding alkoxy lithium ... -
Operando tracking of oxidation-state changes by coupling electrochemistry with time-resolved X-ray absorption spectroscopy demonstrated for water oxidation by a cobalt-based catalysts film
(2021)Transition metal oxides are promising electrocatalysts for water oxidation, i.e., the oxygen evolution reaction (OER), which is critical in electrochemical production of non-fossil fuels. The involvement of oxidation state ... -
Optimization of semiochemical-based trapping of Metamasius hemipterus sericeus (Olivier) (Coleoptera: Curculionidae)
(1996-08)Response of adults of the West Indian sugarcane weevil,Metamasius hemipterus sericeus, to various semiochemical treatments and physical trap designs was studied in southern Florida in field-grown banana and Canary Island ... -
Oral administration of Costa Rican guava (Psidium friedrichsthalianum) juice induces changes in urinary excretion of energy-related compounds in Wistar rats determined by 1H NMR
(2020-08)Introduction: Psidium friedrichsthalianum fruits have in vitro antioxidant activity and their intake has been suggested to have potential health benefits; however, there is still no evidence on the potential in vivo effect ... -
Orbitals in general chemistry, Part I: The great debate
(2020-08)In Part I of a three-part series, we present an objective survey of the technical literature discussing the inclusion of orbitals in highschool and post-secondary general chemistry. We start with the definition of orbitals. ... -
Orbitals in general chemistry, Part II: Mathematical Realities
(2021)In Part II of a three-part series, we discuss two factors absent from textbooks of general chemistry that are important in a discussion of teaching orbitals. First, atomic orbitals are shown systematically to comprise ... -
Orbitals in general chemistry, Part III: Consequences for Teaching
(2021)In Part III of this series, we undertake a critique of the nature of application of orbitals to describe or to explain the structure and the binding within molecules and materials. Teaching orbitals in introductory chemistry ... -
Organic Acids without a Carboxylic Acid Functional Group
(Journal of Chemical Education 77(7):910-915. July 2000, 2000-07)This paper presents several organic molecules that have been labeled as acids but do not contain a carboxylic acid functional group. The rationale for the nomenclature and appropriate explanations for the apparent acidity ...