Browsing Química by Title
Now showing items 62-81 of 360
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Chemical composition of essential oils of the tree Melaleuca quinquenervia (Myrtaceae) cultivated in Costa Rica
(2021-04-21)Introduction: Melaleuca is a Myrtaceous genus of flowering plants of about 290 species, distributed throughout Indonesia, Papua New Guinea, Australia, and New Caledonia. Objective: To identify the chemical composition of ... -
Chemical Investigations of Tropical Medicinal Plants, XXI [1] Long Chain Alkyl Esters of Ferulic and p-Coumaric Acid from Bauhinia manca
(1986)Bauhibia manca (Leguminosae) is a vine growing in the lowland forests of Costa Rica and Panama [2]. In Costa Rica, an infusion of the stems and leaves is taken as an astringent and diuretic, and as a remedy for diabetes[3,4] ... -
Cinética y Mecanismo de la Transposición Fotoquímica de Benzoiloxifosforinas
(1980)Al irradiar los compuestos organofosforados del tipo benzoiloxifosforinas con luz visible de 380 nm hasta 760 nm en ciclohexano y en ausencia de oxígeno, se obtienen con buenos rendimientos los fosfaciclohexadienos (2) ... -
Clibadiolide, a sesquiterpene lactone esterified with a homoditerpene from Clibadium pittierii
(1988)The aerial parts of Clibadium pittierii afforded in addition to known melampolides two new ones, one being esterified with a homoditerpenic acid and the homoditerpenic acid itself. The structures were elucidated by high ... -
Co-adsorbing effect of bile acids containing bulky amide groups at 3β-position on the photovoltaic performance in dye-sensitized solar cells
(2019)Co-adsorbing molecules attain certain control in the surrounding of the dyes leading to enhanced efficiencies mainly by affecting the recombination of the photogenerated electrons and aggregation of dyes. Bile acids ... -
Composition, Chemical Fingerprinting and Antimicrobial Assessment of Costa Rican Cultivated Guavas (Psidium friedrichsthalianum (O. Berg) Nied. and Psidium guajava L.) Essential Oils from Leaves and Fruits
(2016-07-28)The essential oil of two related tree species, P. friedrichsthalianum and P. guajava, where obtained. A total of six different oil samples were recovered including leaves in dry/rainy season and fruits of both plant species. ... -
Concomitant prediction of environmental fate and toxicity of chemical compounds
(2020)The environmental fate of many functional molecules that are produced on a large scale as precursors or as additives to specialty goods (plastics, fibers, construction materials, etc.), let alone those synthesized by the ... -
Condensación de Cetonas Alifáticas con la Fenantrenoquinona en Hidróxido de Amonio
(1971)A study on the synthesis and structure of the products of condensation of phenanthrenequinone with acetone and methyl-ethyl-ketone in presence of ammonia was made. The structures were established by spectroscopic methods. ... -
Constituents of Fevillea cordifolia: New Norcucurbitacin and Cucurbitacin Glycosides
(1993)The seeds of Fevillea cordifolta have yielded 11 new fevicordin-type 29- norcucurbitacins 3-13, and two new cucurbitacin glycosides 14 and 15, which were isolated along with previous reported fevicordin A [2] and its ... -
Costa Rican Propolis Chemical Compositions: Nemorosone Found to Be Present in an Exclusive Geographical Zone
(2023-10-14)Background: The chemistry of Costa Rican propolis from Apis mellifera remains underexplored despite its potential applications. This study identified its chemical composition, linking chemotypes to antioxidant potential. ... -
Crecimiento de estructuras de carbono mediante deposición química en fase de vapor a baja presión
(2022)Los alótropos de carbono han ganado interés en las últimas décadas debido a sus propiedades y a la gran variedad de posibles aplicaciones tecnológicas que han demostrado. Por dichas razones, la obtención de estos alótropos ... -
Critical Assessment of pH-Dependent Lipophilicity Profiles of Small Molecules: Which One Should We Use and In Which Cases?
(2023-10-03)Lipophilicity is a physicochemical property with wide relevance in drug design, computational biology, food, environmental and medicinal chemistry. Lipophilicity is commonly expressed as the partition coefficient for neutral ... -
Crystal structure of (E)-2-(tert-butylamino)-4-(tertbutylimino)naphthalen-1(4H)-one
(2018)The title compound, C18H24N2O, is the first example of a naphthoquinone imine derivative isolated in the 4-imine/2-amine tautomeric form having bulky alkyl substituents at the N atoms. The molecular conformation is stabilized ... -
Crystal structure of 4-[(adamantan-1-yl)amino]naphthalene-1,2-dione
(2019)The title compound, C20H21NO2, an example of a stable 1,2-naphthoquinone, was determined by single-crystal X-ray diffraction analysis at 100 K. This structure illustrates steric buttressing of the adamantanyl group, forcing ... -
Crystal structures and biological activity of 1,1,4-triphenyl-substituted 1,3-enyne compounds
(2019)1,3-Enyne structural motifs are versatile building blocks in organic synthesis and occur widely in various natural products with many of them being highly active as cytotoxic macrolides and antitumour antibiotics. This ... -
Derivados del 3,4-Dihidro-isoazol
(1978)Synthesis and structure elucidation of the products (3a-e) of condensation of phenanthrenequinone with various ketones in presence of ammonia. -
Derivados del 9,10-Dihidrofenantreno
(1970)La siguiente tesis de licenciatura muestra un estudio de los productos sintéticos obtenidos por la condensación aldólica Schmidt - Claisen de la acetona con la fenantrenoquinona por medios espectroscópicos. -
Derivados del colesterol en el alga roja Laurencia papillosa (Forssk.) Grev.
(1991)La gran mayoría de las algas de la división Rhodophyta contienen colesterol como el contribuye esteroidal C27 mayoritario a pesar de que en algunas especies el desmosterol es el que se encuentra en cantidades apreciables, ... -
Derivados del fenantreno [9,10-d] Imidazol
(1981)A simplified synthetic method of the phenanthro[9,10-d]imidazol (1) is reported in this work. The acetyl derivative (2) and a new cupric complex (3) of the imidazole (1) are synthesized, and the structures assigned on the ...