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Cheol Hong Cheon - One of the best experts on this subject based on the ideXlab platform.
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total syntheses of arcyriaflavin a and calothrixin b using 2 2 bisindole 3 Acetic Acid Derivative as a common intermediate
Organic Letters, 2017Co-Authors: Sungjong Lee, Kyung-hee Kim, Cheol Hong CheonAbstract:A new protocol for the synthesis of 2,2′-bisindole-3-Acetic Acid Derivatives from aldimines derived from 2-aminocinnamic Acid Derivatives and indole-2-carboxaldehyde was developed via a cyanide-catalyzed imino-Stetter reaction. With this protocol, the divergent total syntheses of arcyriaflavin A, a representative indolocarbazole natural product, and calothrixin B, a representative indolo[3,2-j]phenanthridine natural product, were completed using a 2,2′-bisindole-3-Acetic Acid Derivative as the common intermediate.
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Total Syntheses of Arcyriaflavin A and Calothrixin B Using 2,2′-Bisindole-3-Acetic Acid Derivative as a Common Intermediate
2017Co-Authors: Sungjong Lee, Kyung-hee Kim, Cheol Hong CheonAbstract:A new protocol for the synthesis of 2,2′-bisindole-3-Acetic Acid Derivatives from aldimines derived from 2-aminocinnamic Acid Derivatives and indole-2-carboxaldehyde was developed via a cyanide-catalyzed imino-Stetter reaction. With this protocol, the divergent total syntheses of arcyriaflavin A, a representative indolocarbazole natural product, and calothrixin B, a representative indolo[3,2-j]phenanthridine natural product, were completed using a 2,2′-bisindole-3-Acetic Acid Derivative as the common intermediate
Sungjong Lee - One of the best experts on this subject based on the ideXlab platform.
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total syntheses of arcyriaflavin a and calothrixin b using 2 2 bisindole 3 Acetic Acid Derivative as a common intermediate
Organic Letters, 2017Co-Authors: Sungjong Lee, Kyung-hee Kim, Cheol Hong CheonAbstract:A new protocol for the synthesis of 2,2′-bisindole-3-Acetic Acid Derivatives from aldimines derived from 2-aminocinnamic Acid Derivatives and indole-2-carboxaldehyde was developed via a cyanide-catalyzed imino-Stetter reaction. With this protocol, the divergent total syntheses of arcyriaflavin A, a representative indolocarbazole natural product, and calothrixin B, a representative indolo[3,2-j]phenanthridine natural product, were completed using a 2,2′-bisindole-3-Acetic Acid Derivative as the common intermediate.
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Total Syntheses of Arcyriaflavin A and Calothrixin B Using 2,2′-Bisindole-3-Acetic Acid Derivative as a Common Intermediate
2017Co-Authors: Sungjong Lee, Kyung-hee Kim, Cheol Hong CheonAbstract:A new protocol for the synthesis of 2,2′-bisindole-3-Acetic Acid Derivatives from aldimines derived from 2-aminocinnamic Acid Derivatives and indole-2-carboxaldehyde was developed via a cyanide-catalyzed imino-Stetter reaction. With this protocol, the divergent total syntheses of arcyriaflavin A, a representative indolocarbazole natural product, and calothrixin B, a representative indolo[3,2-j]phenanthridine natural product, were completed using a 2,2′-bisindole-3-Acetic Acid Derivative as the common intermediate
Nergis Arsu - One of the best experts on this subject based on the ideXlab platform.
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one component thioxanthone Acetic Acid Derivative photoinitiator for free radical polymerization
Photochemistry and Photobiology, 2014Co-Authors: Duygu Sevinc Esen, Gokhan Temel, Demet Karaca Balta, Xavier Allonas, Nergis ArsuAbstract:Acetic Acid-based thioxanthone (TXCH2 COOH) was synthesized and characterized and used as a photoinitiator for free radical photopolymerization of methyl methacrylate (MMA) in the absence and presence of a tertiary amine (MDEA) in different solvents. Different absorption properties were observed depending on the solvent. Fluorescence and phosphorescence experiments were also carried out successfully. The fluorescence quantum yield was found to be 0.09 and the phosphorescence lifetime was calculated as 138 ms at 77 K. The photoinitiator undergoes efficient intersystem crossing into the triplet state and the lowest triplet state possesses π-π* configuration. Laser flash photolysis experiments show that transient absorption of TXCH2 COOH is similar to the parent thioxanthone and the triplet lifetime was calculated as 2.3 μs at 630 nm.
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mechanistic studies of photoinitiated free radical polymerization using a bifunctional thioxanthone Acetic Acid Derivative as photoinitiator
Macromolecules, 2009Co-Authors: Feyza Karasu, Nergis Arsu, Steffen Jockusch, Nicholas J TurroAbstract:A bifunctional photoinitiator for free radical polymerization, thioxanthone catechol-O,O′-diAcetic Acid, was synthesized, characterized, and compared to photoinitiator parameters of the monofunctional analogue, 2-(carboxymethoxy)thioxanthone. Photophysical studies such as fluorescence, phosphorescence, and laser flash photolysis in addition to photopolymerizations of methyl methacrylate show that the bifunctional photoinitiator is more efficient in polymer generation than the monofunctional Derivative. These studies suggest that initiator radicals are generated from a π−π* triplet state in an intramolecular electron transfer, followed by proton transfer and decarboxylation to generate alkyl radicals, which initiate polymerization. The initial electron transfer is faster for the bifunctional photoinitiator than the monofunctional Derivative, which is based on laser flash photolysis studies. Because of the relatively fast intramolecular radical generation from the triplet state (triplet lifetime = 490 ns), ...
Ysambertt, Fredy José - One of the best experts on this subject based on the ideXlab platform.
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Determinación de fenoles totales en derivados lígnicos obtenidos del licor negro como alternativa de producción
Universidad Centroccidental Lisandro Alvarado, 2018Co-Authors: López Villalobos, María José, Piña Sáenz, Irama Isabel, Abou Masoud Yakelin, Ysambertt, Fredy JoséAbstract:Lignin is an industrial waste being worthless in papermaking byproduct of black liquor obtained from the pulping process in some Venezuelan plants. The black liquor is obtained from the Kraft pulping process to extract lignin sulphite by Acid precipitation and quantify the amount of total phenols in such lignin products used in this study. Spectrophotometry Molecular absorption in the UV-Visible and Infrared Spectroscopy (FTIR) region were used to carry out these study techniques. The products obtained in the study had the same signs than commercial lignin (LA), along with the extracted lignin present little degradation HCl, confirmed by infrared spectra. Also, the amount of total phenols was quantified in Derivative lignin obtained using the Folin-Ciocalteu. In the sulphite process extracted lignin with Acetic Acid Derivative contains more phenols, and in the Kraft process, the Derivative lignin extracted with fewer nitric Acid present. The amount of total phenolics present in these Derivatives are good for making antiseptics, detergents, nylon, resin and many industrial products. , , , , Lignin, waste, precipitation, phenols, antioxidantsLa lignina es un subproducto del licor negro obtenido del proceso de despulpado en algunas plantas de Venezuela, siendo un desecho industrial que carece de valor en la fabricación de papel. En este estudio se utilizó el licor negro obtenido de los procesos de pulpado Kraft y Sulfito para extraer la lignina mediante precipitaciones ácidas y cuantificar la cantidad de fenoles totales en dichos productos lígnicos. Para llevar a cabo este estudio, se utilizaron las técnicas de Espectrofotometría de Absorción Molecular en la región UV-Visible y la Espectroscopia de Infrarrojo (FTIR). Los productos obtenidos en el estudio presentaron señales similares que la lignina comercial (LA), además la lignina extraída con HCl presentó poca degradación, corroborado por los espectros infrarrojos. Asimismo, se cuantificó la cantidad de fenoles totales en los derivados lignicos obtenidos empleando el método de Folin-Ciocalteu. En el proceso de Sulfito el derivado lígnico extraído con ácido acético contiene mayor cantidad de fenoles, y en el proceso de Kraft, el derivado lignido extraido con ácido nítrico presentó menor cantidad. La cantidad de fenoles totales presentes en estos derivados es buena, pudiendo aprovecharse en la elaboración de antisépticos, detergentes, nylon, resina y múltiples productos industria
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Determinación de fenoles totales en derivados lígnicos obtenidos del licor negro como alternativa de producción
2015Co-Authors: Ysambertt, Fredy José, Abou Masoud Yakelin, López Villalobos, José De Jesús, Piña Sáenz IramaAbstract:Lignin is an industrial waste being worthless in papermaking by product of black liquor obtained from the pulping process in some Venezuelan plants. The black liquor is obtained from the Kraft pulping process to extract lignin sulphite by Acid precipitation and quantify the amount of total phenols in such lignin products used in this study. Molecular absorption spectrophotometry in the UV-Visible and Infrared Spectroscopy (FTIR) region were used to carry out these study techniques. The products obtained in the study had the same signs than commercial lignin (LA), along with the extracted lignin present little degradation HCl, confirmed by infrared spectra. Also, the amount of total phenols was quantified in Derivative lignin obtained using the Folin-Ciocalteu. In the sulphite process extracted lignin with Acetic Acid Derivative contains more phenols, and in the Kraft process, the Derivative lignin extracted with fewer nitric Acid present. The amount of total phenolics present in these Derivatives are good for making antiseptics, detergents, nylon, resin and many industrial products.La lignina es un subproducto del licor negro obtenido del proceso de despulpado en algunas plantas de Venezuela, siendo un desecho industrial que carece de valor en la fabricaci´on de papel. En este estudio se utiliz´o el licor negro obtenido de los procesos de pulpado Kraft y Sulfito para extraer la lignina mediante precipitaciones ´Acidas y cuantificar la cantidad de fenoles totales en dichos productos l´ıgnicos. Para llevar a cabo este estudio se utilizaron las t´ecnicas de Espectrofotometr´ıa de Absorci´on Molecular en la regi´on UV-Visible y la Espectroscopa de Infrarrojo (FTIR). Los productos obtenidos en el estudio presentaron se˜nales similares que la lignina comercial (LA), adem´as la lignina extra´ıda con HCl present´o poca degradaci´on, corroborado por los espectros infrarrojos. Asimismo, se cuantific´o la cantidad de fenoles totales en los derivados l´ıgnicos obtenidos empleando el m´etodo de Folin-Ciocalteu. En el proceso de Sulfito el derivado l´ıgnico extra´ıdo con ´Acido ac´etico contiene mayor cantidad de fenoles, y en el proceso de Kraft, el derivado l´ıgnido extra´ıdo con ´Acido n´ıtrico present´o menor cantidad. La cantidad de fenoles totales presentes en estos derivados es buena, pudiendo aprovecharse en la elaboraci´on de antis´epticos, detergentes, nylon, resina y m´ultiples productos industriales
Kyung-hee Kim - One of the best experts on this subject based on the ideXlab platform.
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total syntheses of arcyriaflavin a and calothrixin b using 2 2 bisindole 3 Acetic Acid Derivative as a common intermediate
Organic Letters, 2017Co-Authors: Sungjong Lee, Kyung-hee Kim, Cheol Hong CheonAbstract:A new protocol for the synthesis of 2,2′-bisindole-3-Acetic Acid Derivatives from aldimines derived from 2-aminocinnamic Acid Derivatives and indole-2-carboxaldehyde was developed via a cyanide-catalyzed imino-Stetter reaction. With this protocol, the divergent total syntheses of arcyriaflavin A, a representative indolocarbazole natural product, and calothrixin B, a representative indolo[3,2-j]phenanthridine natural product, were completed using a 2,2′-bisindole-3-Acetic Acid Derivative as the common intermediate.
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Total Syntheses of Arcyriaflavin A and Calothrixin B Using 2,2′-Bisindole-3-Acetic Acid Derivative as a Common Intermediate
2017Co-Authors: Sungjong Lee, Kyung-hee Kim, Cheol Hong CheonAbstract:A new protocol for the synthesis of 2,2′-bisindole-3-Acetic Acid Derivatives from aldimines derived from 2-aminocinnamic Acid Derivatives and indole-2-carboxaldehyde was developed via a cyanide-catalyzed imino-Stetter reaction. With this protocol, the divergent total syntheses of arcyriaflavin A, a representative indolocarbazole natural product, and calothrixin B, a representative indolo[3,2-j]phenanthridine natural product, were completed using a 2,2′-bisindole-3-Acetic Acid Derivative as the common intermediate
