Journal articles: 'Sucres amines'

1

Thomas, Aleena, Baptiste Gasch, Enzo Olivieri, and Adrien Quintard. "Trichloroacetic acid fueled practical amine purifications." Beilstein Journal of Organic Chemistry 18 (February 24, 2022): 225–31. http://dx.doi.org/10.3762/bjoc.18.26.

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Amine purification have for long been dominated by tedious stepwise processes involving the generation of large amounts of undesired waste. Inspired by recent work on out of equilibrium molecular machinery, using trichloroacetic acid (TCA), we disclose a purification technique considerably decreasing the number of operations and the waste generation required for such purifications. At first, TCA triggers the precipitation of the amines through their protonated salt formation, enabling the separation with the impurities. From these amine salts, simple decarboxylation of TCA liberates volatile CO2 and chloroform affording directly the pure amines. Through this approach, a broad range of diversely substituted amines could be isolated with success.

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Ding, Wen, Shaoyu Mai, and Qiuling Song. "Molecular-oxygen-promoted Cu-catalyzed oxidative direct amidation of nonactivated carboxylic acids with azoles." Beilstein Journal of Organic Chemistry 11 (November 11, 2015): 2158–65. http://dx.doi.org/10.3762/bjoc.11.233.

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A copper-catalyzed oxidative direct formation of amides from nonactivated carboxylic acids and azoles with dioxygen as an activating reagent is reported. The azole amides were produced in good to excellent yields with a broad substrate scope. The mechanistic studies reveal that oxygen plays an essential role in the success of the amidation reactions with copper peroxycarboxylate as the key intermediate. Transamidation occurs smoothly between azole amide and a variety of amines.

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3

Rahman, N. A., W. Widiyastuti, and S. P. A. Anggraini. "FUNCTIONALIZATION OF SILICA FROM BAGASSE ASH WITH PRIMARY AMINES: FTIR ANALYSIS." RASAYAN Journal of Chemistry 15, no. 02 (2022): 885–88. http://dx.doi.org/10.31788/rjc.2022.1526177.

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Organic silica from bagasse ash was successfully manufactured as a carbon dioxide gas adsorbent. Moreover, this is accomplished by functionalizing the silica surface's amine groups. Amines have high reactivity to CO2 gas. Using the in-situ method, silanol groups can interact with amine groups. This research employs an in-situ technique in which the hydrolysis and condensation reactions co-occur to form a gel. Infrared spectroscopy was used to assess the efficacy of the functionalization of silanol and amine groups. This work aimed to examine the success of the functionalization of the amine group on the silica surface using infrared spectroscopy to produce carbon dioxide gas as an adsorbent. Fourier-Transform Infrared (FTIR) spectroscopy indicated a shift in silica groups produced by amine functionalization.

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Still, Ian WJ, Rosanne Natividad-Preyra, and F. Dean Toste. "A versatile synthetic route to 1,5-dithiocins from o-mercapto aromatic aldehydes." Canadian Journal of Chemistry 77, no. 1 (January 1, 1999): 113–21. http://dx.doi.org/10.1139/v98-230.

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An earlier procedure for the facile preparation of benzo-fused 1,5-dithiocins 2a-2c from o-mercapto- benzaldehydes has been improved and shown to be capable of extension to the preparation of several naphthalene-derived analogues. The general method also afforded several N-alkylated 1,5-dithiocins 4, 5 by replacing NH3 with the appropriate primary amine. It was found that N-acylation of the 1,5-dithiocins was successful only with methyl chloroformate. Attempted N-phenylation met with limited success but was shown to be unnecessary since even the less reactive aniline readily undergoes the general reaction of primary amines. When simple α-amino acids, or their methyl esters, were employed as the primary amine in the reaction with o-mercaptobenzaldehyde, the formation of the N-alkylated 1,5-dithiocins 4a, 17a,17b with accompanying loss of -COOH or -COOMe was observed, in preparatively useful yields. A mechanism is proposed for this interesting transformation.Key words: 1,5-dithiocins, α-amino acids, N-acylation, decarboxylation.

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Roura Padrosa, David, Zoya Nisar, and Francesca Paradisi. "Efficient Amino Donor Recycling in Amination Reactions: Development of a New Alanine Dehydrogenase in Continuous Flow and Dialysis Membrane Reactors." Catalysts 11, no. 4 (April 20, 2021): 520. http://dx.doi.org/10.3390/catal11040520.

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Transaminases have arisen as one of the main biocatalysts for amine production but despite their many advantages, their stability is still a concern for widespread application. One of the reasons for their instability is the need to use an excess of the amino donor when trying to synthesise amines with unfavourable equilibria. To circumvent this, recycling systems for the amino donor, such as amino acid dehydrogenases or aldolases, have proved useful to push the equilibria while avoiding high amino donor concentrations. In this work, we report the use of a new alanine dehydrogenase from the halotolerant bacteria Halomonas elongata which exhibits excellent stability to different cosolvents, combined with the well characterised CbFDH as a recycling system of L-alanine for the amination of three model substrates with unfavourable equilibria. In a step forward, the amino donor recycling system has been co-immobilised and used in flow with success as well as re-used as a dialysis enclosed system for the amination of an aromatic aldehyde.

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Novak, Levente, Muriel Cocaign-Bousquet, Nicholas D. Lindley, and Pascal Loubière. "Cométabolisme sucre-acides aminés chez Lactococcus lactis." Le Lait 78, no. 1 (1998): 17–22. http://dx.doi.org/10.1051/lait:199813.

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7

Niephaus, Herbert, Gerhard Raabe, and Jörg Fleischhauer. "Quantenchemische Rechnungen an Stickstoffbasen. Teil 4*: Zur Berechnung der Polarisierbarkeiten aliphatischer Amine mit der MINDO /3-FP-Methode." Zeitschrift für Naturforschung A 41, no. 4 (April 1, 1986): 671–77. http://dx.doi.org/10.1515/zna-1986-0413.

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The polarizabilities of some primary, secondary, and tertiary amines have been calculated with the MINDO/3-FP-method. The calculated values are found to correlate with the experimental polarizabilities and with those determined by the method of Miller and Savchik in a satisfying manner. In addition atomic polarizabilities have been calculated according to the method of Metzger. Averaging over the calculated mean atomic polarizabilities of hydrogen, carbon, and nitrogen yields increments which, when used to recalculate molecular polarizabilities, lead to values which correlate in an excellent manner with those determined from densities and refraction indices by means of the Lorenz-Lorentz-equation.Because different nitrogen increments have been determined for primary, secondary and tertiary amines, the parameters presented here make it possible to distinguish between constitutional isomers as long as they belong to different groups (i.e. primary, secondary, and tertiary amines), something which cannot be done using the method of Miller and Savchik. The increments derived do not only allow to predict the polarizabilities of primary, secondary and tertiary amines but can be used to calculate the corresponding values for hydrazines and polyfunctional amines with equal success.

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8

Liu, Jingjing, Jiaxi Xu, Zhenjiang Li, Songquan Xu, Xin Wang, Haixin Wang, Tianfo Guo, Yu Gao, Lei Zhang, and Kai Guo. "Squaramide and amine binary H-bond organocatalysis in polymerizations of cyclic carbonates, lactones, and lactides." Polymer Chemistry 8, no. 45 (2017): 7054–68. http://dx.doi.org/10.1039/c7py01671a.

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9

Régaldo-Saint-Blancard, Pierre. "Les céramiques de raffinage du sucre : typologie - technologie." Archéologie du Midi médiéval 4, no. 1 (1986): 151–68. http://dx.doi.org/10.3406/amime.1986.1125.

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10

Lin, Cheng, Hui Yun Zhang, Xiao Ying Lin, and Yun Fei Feng. "Adsorption CO₂ on Activated Carbon with Surface Modification." Advanced Materials Research 634-638 (January 2013): 746–50. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.746.

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The success of CO2 capture from flue gas with solid sorbent is dependent of a low cost sorbent with high CO2 adsorption capacity and selectivity. Modifying surface texture of activated carbon with impregnating amines is expected to offer the benefits of liquid amines in the typical adsorption process routes. In this work, cocoanut activate carbon (AC) is firstly alkalified by KOH solution, then modified by impregnation of tetraethylenepentamine (TEPA), triethylenetetramine (TATA), and triethanolamine (TEA) to form a new type of sorbents. The effects of alkalifying treatment and temperature on CO2 adsorption capacities of the sorbents are investigated. Results indicate that the activate carbons modified by combining alkalification pretreatment firstly and then impregnated amines at low temperature are profitable for CO2 adsorption. The adsorption capacities of CO2 are enhanced with TEPA and TETA impregnation on the activate carbon pretreated by KOH solution. And CO2 adsorption capacity of new sorbents is stable after many adsorption and desorption cycles.

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11

Raza, Muhammad Fahad, Tianbao Wang, Zhiguo Li, Hongyi Nie, Martin Giurfa, Arif Husain, Pavol Hlaváč, et al. "Biogenic amines mediate learning success in appetitive odor conditioning in honeybees." Journal of King Saud University - Science 34, no. 4 (June 2022): 101928. http://dx.doi.org/10.1016/j.jksus.2022.101928.

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12

Vilariño, Maria, F. Rudeaux, Alicia León, and Michel Picard. "Teneur en énergie métabolisable et digestibilité des acides aminés chez le coq de deux sous-produits de l'extraction de l'huile : tourteau de palmiste pressé (Elaeis guineensis) et germe et son de maïs extrait (Zea mays)." Revue d’élevage et de médecine vétérinaire des pays tropicaux 49, no. 3 (March 1, 1996): 229–34. http://dx.doi.org/10.19182/remvt.9519.

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La digestibilité d'un échantillon de tourteau de palmiste vénézuélien (TP) [contenant 92,2 % de matière sèche (MS) et en pourcentage de MS : 13,5 de protéine brute (PB), 14,6 de matières grasses (MG), 4,6 de matières minérales (MM), 60,7 de parois végétales (PAR) et moins de 1 % d'amidon et de sucres] est mesurée chez neuf coqs nourris ad libitum (30 p. 100 TP + 67 % maïs témoin + 3 % prémélange). La valeur d'énergie métabolisable apparente (EMA) de TP est 1 963 ± 52 kcal/kg MS. La digestibilité vraie moyenne des acides aminés de TP est 48 % (pour la lysine, 26 %). Les mêmes mesures sont faites sur un sous-produit vénézuélien de l'extraction de l'huile et de la farine de maïs contenant les germes et du son (GSME) [85,9 % MS et en p. 100 MS : 14,1 PB, 1,3 MG, 3,9 MM, 34,2 PAR, 44,0 d'amidon et 6,2 de sucres] à 50 % dans le régime de test (+ 47 % maïs témoin + 3 % prémélange). La valeur EMA de GSME est 2 648 ± 28 kcal/kg MS. La digestibilité vraie moyenne des acides aminés de GSME est de 89 % (pour la lysine, 82 %). Les coefficients de digestibilité élevés pour les protéines et l'amidon de GSME facilitent la prédiction de sa valeur EMA pour les volailles à partir de l'analyse chimique. Le TP testé est essentiellement une source de lipides résiduels dont la teneur détermine la valeur nutritionnelle pour les volailles.

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13

Hubert Dieu Béni, Elian, Fotso Fotso, Touckia Gorgon Igor, Djamndo Djasbé Mathurin, and Djeuani Astride Carole. "Influence de la BAP et de l’ANA sur l’évolution des teneurs en sucres solubles et acides aminés totaux dans les tiges des vitroplants du Manihot esculenta Crantz variété TMS 96/1762 au cours de la régénération in vitro directe." European Scientific Journal, ESJ 18, no. 11 (March 31, 2022): 102. http://dx.doi.org/10.19044/esj.2022.v18n11p102.

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L’objectif de cette étude est d’évaluer l’effet de la BAP et de l’ANA sur les varaiations des teneurs en sucres solubles et acides aminés totaux dans les tiges des vitroplants du Manihot esculenta Crantz variété TMS 96/1762 au cours de la régénération in vitro. Pour ce faire, les bourgeons néoformés sur microboutures sont isolés sous la hotte à flux laminaire. Ils ont été ensuite repiqués dans des tubes de cultures contenant le milieu de régénération, constitué de MB auquel on a ajouté 0,05/0,05 et 0,1/0,1 mg.l-1 BAP/ANA. Les sucres solubles et les acides aminés totaux ont été extraits selon la méthode de Saha et Brewer (1994) modifiée. Le dosage des sucres solubles a été effectué selon la méthode de Saha et Brewer (1994). Les acides aminés ont été dosés à la ninhydrine selon la méthode de Yemm et Cocking (1995). Le milieu de culture favorable au microbouturage est le milieu MS + 0,1/0,1mg.l-1 BAP/ANA qui a permis d’obtenir un nombre moyen de feuilles maximal de 6,44 ± 1,89. L’addition de BAP/ANA (0,05/0,05mg.l-1) aux MB a entrainé une baisse de la teneur en sucres solubles. Elle est passée de 530,932 µg/g de PF au jour 7 à 507 µg/g de PF puis elle était devenue élevée jour 28 (684,152 µg/g de PF). L’utilisation de la combinaison BAP/ANA aux concentrations de 0,05/0,05 mg.l-1 et de 0,1/0,1mg.l-1 dans les MB a respectivement engendré des pics de la teneur en acides aminés totaux au jour 14 (101831,5 mg/g de PF) et au jour 28 (167948,7mg/g de PF). The objective of this study was to evaluate the effect of BAP and NAA on changes in soluble sugar and total amino acid contents in stems of Manihot esculenta Crantz variety TMS 96/1762 during in vitro regeneration. For this purpose, buds neoformed on microbuds were isolated under the laminar flow hood. They were then transplanted into culture tubes containing the regeneration medium, consisting of MB to which 0.05/0.05 and 0.1/0.1 mg.l-1 BAP/ANA were added. Soluble sugars and total amino acids were extracted according to the modified method of Saha and Brewer (1994). The determination of soluble sugars was performed according to the method of Saha and Brewer (1994). Amino acids were assayed with ninhydrin according to the method of Yemm and Cocking (1995). The culture medium favorable for micro bottling was MS + 0.1/0.1mg.l-1 BAP/ANA, which resulted in a maximum average leaf count of 6.44 ± 1.89. The addition of BAP/ANA (0.05/0.05mg.l-1) to MB resulted in a decrease in soluble sugar content. It went from 530.932 µg/g FP on day 7 to 507 µg/g FP and then became high on day 28 (684.152 µg/g FP). The use of BAP/ANA combination at the concentrations of 0.05/0.05 mg.l-1 and 0.1/0.1mg.l-1 in MB resulted in peaks in total amino acid content at day 14 (101831.5 mg/g FP) and day 28 (167948.7mg/g FP), respectively.

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14

Darquié, Benoît. "Vers une mesure de la brisure de la parité dans les molécules." Reflets de la physique, no. 73 (July 2022): 16–20. http://dx.doi.org/10.1051/refdp/202273016.

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Le vivant n’a sélectionné qu’une seule des deux formes, droite ou gauche, de molécules chirales aussi essentielles que les acides aminés ou les sucres. Les causes de cette asymétrie restent un mystère mais, d’après les prédictions théoriques, l’interaction nucléaire faible serait à l’origine d’une infime différence d’énergie entre les deux formes. Les enjeux relatifs à une première mesure de cette différence d’énergie sont présentés ici. Cette mesure apporterait une lumière précieuse sur un sujet qui touche à la fois à l’origine de la vie et à la physique fondamentale.

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15

Pusey, Marc, Michelle Morris, Jorge Barcena, Qunying Yuan, and Joseph Ng. "Optimization of Cryptic Leads from Trace Fluorescent Labeling Screening." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1155. http://dx.doi.org/10.1107/s2053273314088445.

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We use trace fluorescent labeling (TFL) as a means of rapidly identifying crystals in the screening plate. The method involves the covalent labeling of between 0.1 to 0.2 % of the protein molecules with a fluorescent probe. Our standard labeling process uses the amine reactive dye 5(6)-carboxyrhodamine 6G succinimidyl ester (Invitrogen, C-6157), with reaction conditions (pH) adjusted to label random side chain amines. Previous results had shown that labeling below 1% does not affect the nucleation rate or diffraction data quality. Identification of crystalline outcomes is based on intensity; (labeled) protein packing density is highest in the crystalline form which will fluoresce more brightly than other precipitated forms. We found that there were many outcomes where the fluorescent images had regions of high intensity, but no corresponding crystalline structures were apparent using white light transmission microscopy. Under the governing paradigm, that intensity = structure, we hypothesized that these were likely lead conditions and tested that hypothesis with optimization screening using capillary counter diffusion (CCD). Four CCD experiments are set up for each lead condition experiment having different ratios of the stock screening cocktail components. The capillaries (40 mm long, 0.3, 0.2, or 0.1 mm ID) are filled with protein at 2.5X the sitting drop screening experiment concentration, sealed at one end using soft wax, then inserted open end down into 40 uL of the precipitant solution in a 1.2 mL titer tube (E&K Scientific, cat.# 684510-R), which is then sealed with a stopper (E&K Scientific, cat.# 64108-P). The capillaries can be examined using a microscope through the walls of the tube, using either white light or fluorescence illumination. We are currently finding ~40% of the identified lead conditions yield crystals upon optimization, representing a significant increase in the success rate for the screening experiment.

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16

Bond, Patrick. "Truncated 21st-Century Trajectories of Progressive International Solidarity." Journal of World-Systems Research 25, no. 2 (September 3, 2019): 259–69. http://dx.doi.org/10.5195/jwsr.2019.948.

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Patrick Bond provides a biography of Amin’s work as a global political thinker and leader on the left. From his early days building the Third World Forum and establishing “origins of a South-centric organic intelligentsia with global visions” to his work with the World Social Forum process, Amin dedicated his life to trying to lay the foundations for a Fifth International. Bond notes Amin’s frustration with the extreme fragmentation and limited policy impacts of left struggles. Yet he points out some recent exceptions here in the successes of global South campaigns around the right to water, access to medicines and the right to health, and Via Campesina and MST’s success in building global resistance to corporate land grabbing.

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Rana, Anil, Varun Kumar, Lata Tiwari, Anamika Thakur, Chhuttan Meena, and Dinesh Mahajan. "Triflic Anhydride Promoted Synthesis of Primary Amides and their Conversion into Nitriles." SynOpen 02, no. 02 (April 2018): 0180–91. http://dx.doi.org/10.1055/s-0037-1610154.

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A facile, two-pot conversion of carboxylic acids into the corresponding nitriles has been developed using triflic anhydride as a promoter and aqueous NH4OH as a source of nitrogen. The methodology involves synthesis of primary amides from carboxylic acids as the key first step using triflic anhydride and aqueous NH4OH as a source of nitrogen. Triflic anhydride is also found to be an excellent reagent for conversion of primary amides into nitriles, affording high yields with considerable chemoselectivity and functional group tolerance. In spite of the mild reaction conditions and broad substrate scope for the two-step conversions, all attempts for one-pot domino conversion of acids into nitriles exhibited limited success because of poor yields.

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18

Felden, Antoine, Carolina Paris, David G. Chapple, Andrew V. Suarez, Neil D. Tsutsui, Philip J. Lester, and Monica A. M. Gruber. "Native and introduced Argentine ant populations are characterised by distinct transcriptomic signatures associated with behaviour and immunity." NeoBiota 49 (August 19, 2019): 105–26. http://dx.doi.org/10.3897/neobiota.49.36086.

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Biological invasions can be influenced by trait variation in the invader, such as behavioural traits and ecological factors, such as variation in pathogen pressure. High-throughput nucleotide sequencing has increased our capacity to investigate the genomic basis of the functional changes associated with biological invasions. Here, we used RNA-sequencing in Argentina and California, Australia and New Zealand to investigate if native and introduced Argentine ant populations were characterised by distinct transcriptomic signatures. We focused our analysis on viral pressure and immunity, as well as genes associated with biogenic amines known to modulate key behaviour in social insects. Using a combination of differential expression analysis, gene co-expression network analysis and candidate gene approach, we show that native and introduced populations have distinct transcriptomic signatures. Genes associated with biogenic amines were overall up-regulated in the native range compared to introduced populations. Although we found no significant variation in overall viral loads amongst regions for viruses known to infect Argentine ants, viral diversity was lower in most of the introduced range which was interestingly associated with down-regulation of the RNAi immune pathway, primarily directed against viruses. Altogether, our data show that Argentine ant populations exhibit range-specific transcriptomic signatures, perhaps reflecting regional adaptations that may contribute to the ecological success of introduced populations.

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Cerdá, Xim, Louise van Oudenhove, Carlos Bernstein, and Raphaël R. Boulay. "A List of and Some Comments about the Trail Pheromones of Ants." Natural Product Communications 9, no. 8 (August 2014): 1934578X1400900. http://dx.doi.org/10.1177/1934578x1400900813.

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Ants use many different chemical compounds to communicate with their nestmates. Foraging success depends on how efficiently ants communicate the presence of food and thus recruit workers to exploit the food resource. Trail pheromones, produced by different exocrine glands, are a key part of ant foraging strategies. By combing through the literature, we compiled a list of the identity and glandular origin of the chemical compounds found in the trail pheromones of 75 different ant species. Of the 168 compounds identified, more than 40% are amines. In the subfamily Myrmicinae, trail pheromones are mostly produced in the venom gland, while in the subfamily Formicinae, they come from the rectal gland.

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Kwon, Soonjin, Seongjoon Yoo, Hanku Lee, Changhee Han, Kangseok Kim, and Wonil Kim. "Increasing Search Success Rate by Comparing Queries Formation Patterns." Applied Mathematics & Information Sciences 8, no. 1L (April 1, 2014): 149–55. http://dx.doi.org/10.12785/amis/081l19.

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Czopik, Barbara, Monika Ciechomska, Joanna Zarzecka, Maciej Góra, and Michał Woźniakiewicz. "Insight into the Reaction of Alexidine with Sodium Hypochlorite: A Potential Error in Endodontic Treatment." Molecules 26, no. 6 (March 15, 2021): 1623. http://dx.doi.org/10.3390/molecules26061623.

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Therapeutic success in endodontic treatment depends on successful infection control. Alexidine dihydrochloride (ALX) was recently proposed as a potential alternative to 2% chlorhexidine (CHX) as it possesses similar antimicrobial properties, expresses substantivity and does not produce p-chloroaniline (PCA) when mixed with sodium hypochlorite (NaOCl). However, the products released in this reaction have not been described to date. The aim of this study was to identify detected chemical compounds formed in the reaction of ALX and NaOCl with the ultra-high-performance liquid chromatography–mass spectrophotometry (UHPLC-MS) method and assess whether precipitates and PCA are formed in this reaction. Solutions of ALX were mixed with the equivalent volume of 2% and 5.25% (w/v) NaOCl solutions. As control, 2% (w/v) CHX was mixed with 2% and 5.25% (w/v) NaOCl. Samples were subjected to the UHPLC-MS analysis. The mixture of ALX and NaOCl resulted in a yellowish precipitate formation, the amount of which depended on NaOCl concentration. Interaction of ALX and NaOCl resulted in the production of aliphatic amines. No PCA was formed when NaOCl was mixed with ALX. However, for the first time, we identified the possible products of the interaction. The interaction between NaOCl and ALX results in the formation of aliphatic amines; therefore, these compounds should not be mixed during endodontic treatment.

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Elofson, Richard M., Fahmi F. Gadallah, and James K. Laidler. "Bicyclization of aza-compounds by positive halide ions. II. Lactams and some related cyclizations." Canadian Journal of Chemistry 65, no. 12 (December 1, 1987): 2770–73. http://dx.doi.org/10.1139/v87-460.

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Anodic oxidation of lactams in the presence of halide ions produced excellent yields of bicyclic compounds with reactants having rings in the range of eight to ten atoms (C7 to C9). Smaller rings did not react to form bicyclic products and larger rings gave reduced yields. Attempts were made to cyclize non-cyclic amides and to bicyclize cycloheptyl and cyclooctyl acetamide with limited success.

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Bockman, Anna R., and Jeffrey M. Pruet. "Exploring the scope of DBU-promoted amidations of 7-methoxycarbonylpterin." Beilstein Journal of Organic Chemistry 16 (March 26, 2020): 509–14. http://dx.doi.org/10.3762/bjoc.16.46.

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The synthetic utility of pterins is often hampered by the notorious insolubility of this heterocycle, slowing the development of medicinally relevant pteridine derivatives. Reactions which expedite the development of new pterins are thus of great importance. Through a dual role of diazabicycloundecene (DBU), 7-carboxymethylpterin is converted to the soluble DBU salt, with additional DBU promoting an ester-to-amide transformation. We have explored this reaction to assess its scope and identify structural features in the amines which significantly affect success, monitored the reaction kinetics using a pseudo-first order kinetics model, and further adapted the reaction conditions to allow for product formation in as little as 5 min, with yields often >80%.

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Bennett, Lisa K., and Fred T. Davies. "In Vitro Propagation of Quercus shumardii Seedlings." HortScience 21, no. 4 (August 1986): 1045–47. http://dx.doi.org/10.21273/hortsci.21.4.1045.

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Abstract Single node stem sections of Quercus shumardii Buckl. seedlings were used to propagate Shumard oak in vitro. Stem sections in liquid woody plant medium (WPM) with 8.9 μm (2 mg liter−1) BA produced the greatest number of shoots ≥10 mm. The cytokinin 2iP did not promote axillary shoot growth. Shoots were rooted with 73% success under ex vitro conditions in Jiffy-7 peat pellets after a basal dip in 2.5 μm (0.5 g-liter−1) IBA. Plantlets were acclimatized successfully to greenhouse conditions. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA), N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP), 1H-indole-3-butanoic acid (IBA), (1α,2β,4aα,4bβ,10β)-2,4a,7-trihy- droxy-1-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone (GA3).

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Xia, Xiao-Feng, Guo-Wei Zhang, An-Xi Zhou, and Wei He. "Copper-Catalyzed Base-Free N-Arylation of 8-Aminoquinoline Amides through Chelation Assistance." Synlett 29, no. 17 (September 11, 2018): 2269–74. http://dx.doi.org/10.1055/s-0037-1610906.

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A new and efficient approach for the N-arylation of 8-aminoquinoline amides with diaryliodonium salts has been developed. This chelation-assisted selective C–N cross-coupling reaction gave the desired N-arylated 8-aminoquinoline in moderate to good yields. In contrast to previous reports, no additional ligands and bases are used in this transformation. In addition, the anion of the diaryliodonium salt plays an important role in the success of the process.

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Wulan, Fia Fathiana, Tutik Dwi Wahyuningsih, Jumina Jumina, and Naresh Kumar. "Synthesis Studies of N-Acetyl Glyoxylamide Derivatives Using Unreactive Amines." Key Engineering Materials 884 (May 2021): 312–19. http://dx.doi.org/10.4028/www.scientific.net/kem.884.312.

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This research was performed to synthesize the glyoxylamide made from N-acetylisatin and anthranilic acid derivatives. The synthesis was conducted in two steps, starting from the formation of glyoxylamide using N-acetylisatin and methyl anthranilate as the starting material. The reaction was performed under reflux and inert nitrogen gaseous atmosphere for 48 h in the presence of DIPEA in acetonitrile (ACN) solvent. However, that reaction has proven to be unsuccessful. Several strategies were performed to increase the ease of glyoxylamide syntheses, such as increasing the electrophilicity of the isatin ring and increasing the nucleophilicity of the amine. The methyl anthranilate derivatives, methyl-2-amino-5-methoxybenzoate, and methyl-2-amino-4-methoxybenzoate has already been used and proven to be success to ring open the N-acetylisatin and produced glyoxylamide 5 and 6 with a yield of 12% and 11%, respectively. Thus, the desired benzoic acid functional group obtained from the hydrolysis of 5 and 6 successfully produced glyoxylamide 7 and 8 with a yield of 52% and 42%, respectively.

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Arote, Rohidas B., Tae Hee Kim, You Kyoung Kim, Dhananjay Jere, Hu Lin Jiang, In Young Park, Myung Haing Cho, Jae Woon Nah, and Chong Su Cho. "Novel Poly(Ester Amine) Based on Polycaprolactone and Polyethylenimine as a Gene Carrier: Effect of Hydrophobicity on Transfection Efficiency and Cytotoxicity." Key Engineering Materials 342-343 (July 2007): 453–56. http://dx.doi.org/10.4028/www.scientific.net/kem.342-343.453.

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Novel, biodegradable poly(ester amine)s (PEAs) were synthesized using hydrophobic polycaprolactone diacrylate (PCLDA) and highly cationic polyethylenimine (PEI). This novel gene carrier can form stable DNA complexes with particle sizes around 200 nm, and showing excellent transfection efficiency and relatively low cytotoxicity compared with PEI 25K. Effect of hydrophobicity on transfection efficiency and cytotoxicity was profound and was relatively important parameter for the success of gene delivery.

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Beeson, Richard C., and William M. Proebsting. "Picea Graft Success: Effects of Environment, Rootstock Disbudding, Growth Regulators, and Antitranspirants." HortScience 24, no. 2 (April 1989): 253–54. http://dx.doi.org/10.21273/hortsci.24.2.253.

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Abstract Several techniques were tested to improve the development of Colorado blue spruce (Picea pungens Engelm. ‘Hoopsi’) grafts. In the Pacific Northwest, Picea grafts are normally made on active rootstocks in heated greenhouses between December and mid-March. Grafting on dormant rootstocks and holding these grafts in an unheated, polyethylene-covered lath house resulted in generally higher graft success. IBA, NAA, and BA applied to the base of the scion just before grafting increased graft success by 10% to 13%. Retarding the development of the rootstock by dikegulac applications or by bud removal stimulated scion growth. Polyethylene tents and a film-forming anti-transpirant had no effect on graft success. Chemical names used N-(phenylmethyl)-1H-purin-6-amine (BA); 2,3:4,6-bis-0-(l-methylethylidone)-a-l-xylo-2-hexulofuranosonic acid (dikegulac); 1H-indole-3-butyric acid (IBA); 1-naphthaleneacetic acid (NAA).

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Carlisi, Jacqueline A., and Kenneth C. Torres. "In Vitro Shoot Proliferation of Camellia ‘Purple Dawn’." HortScience 21, no. 2 (April 1986): 314. http://dx.doi.org/10.21273/hortsci.21.2.314.

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Abstract Success with in vitro propagation of camellias has been limited to juvenile material of Camellia japonica L. (1, 2, 6). Beauchesne (1) obtained callus from meristems cultured on either Knops or Murashige and Skoog (MS) medium (2) amended with 1H- indole-3-butanoic acid (IBA), N-(phenyl-methyl)-1H-purin-6-amine (BA), gibberellic acid (GA3), and (2,4-dichlorophenoxy) acetic acid (2,4-D). Callus proliferated rapidly when cotyledons of camellias were cultured on a diluted (MS) medium (2). Subculturing the callus onto fresh media resulted in plantlet formation; however, no data were reported on multiplication rates to support these findings. More recently, Samartin et al. (6) reported callus formation from juvenile nodal explants of Camellia cultured on a modified MS medium supplemented with N-(2-fur-anylmethyl)-1H-purin-6-amine (kinetin) (4.6 μM) and BA (4.4 μM). The objectives of this research were to define some of the requirements for shoot proliferation of mature Camellia ‘Purple Dawn’ in vitro.

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Faria, Joao L. C., and Juan Segura. "Micropropagation of Yellow Passionfruit by Axillary Bud Proliferation." HortScience 32, no. 7 (December 1997): 1276–77. http://dx.doi.org/10.21273/hortsci.32.7.1276.

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A protocol for in vitro propagation in yellow passionfruit (Passiflora edulis F. flavicarpa Deg) has been developed. Shoot apices from aseptically grown seedlings were used as initial explants. Multiple shoot formation was obtained by placing the explants on solidified Murashige and Skoog medium containing BA. Regenerated shoots were rooted on media without growth regulators. Following conventional procedures, plantlets were transferred to soil with more than 90% success. Chemical name used: N-(phenylmethyl)-lH-purin-6-amine (BA).

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van Wijk, W. E. "Sur Quelques Amides D'acides du Groupe des Sucres. Contribution à la Connaissance de la Relation Entre la Constitution et le Pouvoir Rotatoire." Recueil des Travaux Chimiques des Pays-Bas 40, no. 4 (September 3, 2010): 221–46. http://dx.doi.org/10.1002/recl.19210400403.

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Rhee, Sang Hoon, Sun Ja Lee, Young Mi Kang, Yong Keun Lee, Bum Soon Lim, and Seung Jin Lee. "Synthesis of Poly(ε-Caprolactone)-Organosiloxane Hybrid Containing Amine Group." Key Engineering Materials 330-332 (February 2007): 1277–80. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.1277.

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Novel poly(ε-caprolactone)-organosiloxane hybrid containing amine group was synthesized through sol-gel method. Triethoxysilane end-capped poly(ε-caprolactone) was prepared by reaction with α,ω-hydroxyl poly(ε-caprolactone) and 3-isocyanatopropyl triethoxysilane. It was then hydrolyzed and co-condensed with aminopropyl triethoxysilane through sol-gel method. The success of hybridization was evaluated by FT-IR by new formation of siloxane group. Osteoblast-like cell responses were assessed on this new hybrid material for the potential application as a bone tissue engineering scaffold. The cell responses were compatible with those on pure poly(ε-caprolactone) used as a control.

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Noh, Hyun Sung, and Jaehan Jung. "Synthesis of Organic–Inorganic Hybrid Nanocomposites via a Simple Two-Phase Ligands Exchange." Science of Advanced Materials 12, no. 3 (March 1, 2020): 326–32. http://dx.doi.org/10.1166/sam.2020.3644.

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The surface of nanocrystals (NCs) was precisely engineered with bifunctional ligands via a simple yet effective two-phase ligand exchange strategy where the introduction of bifunctional ligands and displacement of insulating aliphatic ligands are simultaneously occurred. This is advantageous compared to conventional ligands exchange procedure where the desired ligands are often introduced through two-step processes after treating NC surface with short mobile ligands such as pyridine or short amines. In this study, 4-azidobenzoic acid possessing carboxylic acid for binding with NCs and azide group for chemical coupling was utilized as bifunctional ligands. A correlation between the concentration and the efficiency of ligands replacement was corroborated by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (1H NMR) spectroscopy measurement. Lastly, organic–inorganic nanocomposites were crafted via click coupling between 1-octyne and azidobenzoic acid capped CdSe NCs. The success of coupling was substantiated by FTIR and 1H NMR.

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Sheikhi Mehrabadi, Fatemeh, Hanxiang Zeng, Mark Johnson, Cathleen Schlesener, Zhibin Guan, and Rainer Haag. "Multivalent dendritic polyglycerolamine with arginine and histidine end groups for efficient siRNA transfection." Beilstein Journal of Organic Chemistry 11 (May 13, 2015): 763–72. http://dx.doi.org/10.3762/bjoc.11.86.

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The success of siRNA-based therapeutics highly depends on a safe and efficient delivery of siRNA into the cytosol. In this study, we post-modified the primary amines on dendritic polyglycerolamine (dPG-NH2) with different ratios of two relevant amino acids, namely, arginine (Arg) and histidine (His). To investigate the effects from introducing Arg and His to dPG, the resulting polyplexes of amino acid functionalized dPG-NH2s (AAdPGs)/siRNA were evaluated regarding cytotoxicity, transfection efficiency, and cellular uptake. Among AAdPGs, an optimal vector with (1:3) Arg to His ratio, showed efficient siRNA transfection with minimal cytotoxicity (cell viability ≥ 90%) in NIH 3T3 cells line. We also demonstrated that the cytotoxicity of dPG-NH2 decreased as a result of amino acid functionalization. While the incorporation of both cationic (Arg) and pH-responsive residues (His) are important for safe and efficient siRNA transfection, this study indicates that AAdPGs containing higher degrees of His display lower cytotoxicity and more efficient endosomal escape.

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Falcetti, Mario, and Attilio Scienza. "Influence de la densité de plantation et du porte-greffe sur la production et la qualité du moût de Pinot blanc et de Chardonnay cultivés en Italie dans le Trentin." OENO One 23, no. 3 (September 30, 1989): 151. http://dx.doi.org/10.20870/oeno-one.1989.23.3.1241.

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De nombreux chercheurs ont montré l'influence, soit quantitative soit qualitative, de la diminution du nombre de pieds à l'hectare.Les auteurs, dans une série d'expériences conduites de 1983 à 1986 dans le Trentin en Italie, ont mis en relief l'effet de la densité de plantation sur le bois de taille, sur la production de raisin par pied, ainsi que sur les teneurs en sucres, en acidité et en acides aminés; ces données ont été complétées par des microvinifications et par une analyse sensorielle des vins. Le portegreffe, employé comme moyen pour réduire la vigueur, s'est révélé comme peu important pour les hautes densités, même s'il est à noter une signification de l'interaction « année x portegreffe ».En définitive, ce sont les densités moyennes (3.333 et 4.167 pieds par hectare) qui fournissent les meilleurs résultats dans la pratique viticole de la région (mode de conduite en pergola).

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Simard, Majella. "La contribution du modèle de renforcement des capacités dans la mise en oeuvre de la démarche MADA : études de cas en Acadie du Nouveau-Brunswick." Francophonies d'Amérique, no. 44-45 (February 5, 2019): 115–36. http://dx.doi.org/10.7202/1055907ar.

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Implanté en 2005 par l’Organisation mondiale de la santé, le réseau Municipalités amies des aînés a pour objectif d’améliorer la qualité de vie des aînés. Au Nouveau-Brunswick, 13 municipalités en font partie. Le but de cet article consiste à examiner les effets de la gestion territoriale du vieillissement en matière de développement dans deux MADA. L’approche méthodologique repose sur l’observation participante. Le modèle de renforcement des capacités sert de cadre théorique à la présentation des résultats. Ceux-ci révèlent le rôle de la mobilisation, de la concertation, du leadership et de la transparence de l’information dans le succès de la démarche.

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Ahmed, Naeem, Asad Masood, Kim S. Siow, M. F. Mohd Razip Wee, Rahmat Zaki Auliya, and Wai Kuan Ho. "Effect of H2O-Based Low-Pressure Plasma (LPP) Treatment on the Germination of Bambara Groundnut Seeds." Agronomy 11, no. 2 (February 14, 2021): 338. http://dx.doi.org/10.3390/agronomy11020338.

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In general, seed germination is improved by low-pressure plasma (LPP) treatment using precursors such as air, nitrogen, argon, or water (H2O). Here, H2O-based LPP treatment using the optimized parameters of 10 W and 10 s improves the germination of Bambara groundnut seeds by 22%. LPP increases the wettability and roughness of the seed hilum while oxidizing the surface with carboxyl and amine groups. In this H2O-based treatment of Bambara groundnut seeds, combinatory etching and chemical modification facilitated the imbibition process and increased the germination percentage. The success of this method has the potential to be scaled up to solve food security with seeds otherwise facing germination-related issues.

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Engle, Keary, and John Gurak. "Regioselective Hydroamination Using a Directed Nucleopalladation/Protodepalladation Strategy." Synlett 28, no. 16 (August 2, 2017): 2057–65. http://dx.doi.org/10.1055/s-0036-1589077.

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Alkene hydroamination is an attractive approach for converting alkenes into structurally complex amine products. Several different strategies have been pursued over the past few decades to achieve this historically challenging reaction. One of the key issues associated with this transformation is control of regioselectivity, which is particularly difficult for internal non-conjugated alkenes. Our group has recently found success using a removable bidentate auxiliary to control regioselectivity and stabilize the key nucleopalladated intermediate in a palladium(II)-catalyzed alkene hydroamination with N–H nucleophiles. This article describes the historical context for this work, the underlying conceptual logic, our results to date, and the future outlook.

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Magini, Marcio, and Máira R. Rodrigues. "Dynamical Model to Describe the Interactions between the Chemical Components in Environment of Photopolymerization of MMA by Dye/Amine Systems." Research Letters in Organic Chemistry 2008 (January 25, 2008): 1–5. http://dx.doi.org/10.1155/2008/404936.

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This work discusses the model that explains the aspects of photopolymerization of methyl methacrylate initiated by dye/amine systems. This model is based on a simulation that uses differential equations. A similar model following the hypothesis presented here was used with success in a preliminary work, by Magini and Rodrigues (2005), to describe the cationic photopolymerization of THF in the presence of sensitizers/sulfonium salt systems. Using the same structure was possible to generate a straight correlation between experimental and theoretical results for this system, free radically initiated, opening an important theoretical understanding about the photopolymerization systems and their chemical relations during the reaction.

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Graziano, Antimo, Shaffiq Jaffer, and Mohini Sain. "Graphene oxide modification for enhancing high-density polyethylene properties: a comparison between solvent reaction and melt mixing." Journal of Polymer Engineering 39, no. 1 (December 19, 2018): 85–93. http://dx.doi.org/10.1515/polyeng-2018-0106.

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Abstract Graphene oxide (GO) was chemically modified in xylene with dodecyl amine and hydrazine monohydrate to obtain reduced functionalized graphene oxide (RFGO). Composites of high-density polyethylene (HDPE) and GO were made via solvent reaction, whereas both melt mixing and solvent reaction were used for HDPE-RFGO composites for comparison purposes. Elemental and thermal analysis showed the success of GO modification in grafting amine functionalities onto its structure and restoring most of the original graphene C=C bonds. A significant increase in mechanical properties, thermal stability, and crystallization behavior was observed for HDPE-RFGO (solvent) compared with HDPE and HDPE-GO, proving that homogeneous dispersion of RFGO in the polymer matrix and strong interactions between them resulted in facilitated stress transfer, delayed thermal degradation, and more efficient nucleating effect in inducing the crystal growth of HDPE. A comparison of HDPE-RFGO properties enhancement between the melt mixing method and the solvent reaction method showed that, apart from mechanical behavior, the RFGO contribution was the same, suggesting that the optimization of the ecofriendlier approach (melt) could eventually lead to its total use for the mass production of high-performance, cost-effective, and more environmentally friendly graphene-based thermoplastic polyolefin nanocomposites suitable for highly demanding industrial applications.

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Chen, Pei Pei, Chun Ming Zheng, Xiang Zhi Chen, Zhi Wu Yang, Jun Xia, Ming Lin Guo, and Xiao Hong Sun. "Synthesis and Characterization of Non-Surfactant Mesoporous Chitosan/Silica Composite Sorbent and its Purification of Sugarcane Juice Bioresources." Applied Mechanics and Materials 700 (December 2014): 286–89. http://dx.doi.org/10.4028/www.scientific.net/amm.700.286.

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Mesoporous chitosan-silica composite sorbent has been successfully synthesized by a simple and facile template-free hydrolyzing route from single cheap silica precursor of sodium silicate. The overall decolorization efficiency and capacity for sugar juice between pure chitosan and composite sorbent are very close in field pilot-scale, while much lower quantity of chitosan (only 10 wt.%) is used to build the composite sorbent. The success of increased purification performance and sorption capacity of sugar juice is ascribed to the appropriate pore structure of the composite sorbent with high surface area (395 m2/g), large pore size (7.73×10-9 m) and high percentage of accessible free amine groups of chitosan (70 %).

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THAI, DU X., VAN V. TRAN, SUONG K. NGO, UYEN V. NGUYEN, and T. S. TRAN. "COMPOSITION EN PROTEINES ET EN ACIDES AMINES DES CELLULES DE CANNE A SUCRE D’UNE LIGNEE TOLERANTE A UN MILIEU RICHE EN LYSINE ET EN THREONINE." Canadian Journal of Plant Science 69, no. 2 (April 1, 1989): 625–29. http://dx.doi.org/10.4141/cjps89-078.

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A cell line selection was carried out on sugarcane (Saccharum officinarum L.) callus, and the F. 156 (LT2) line having a high capability to produce lysine and threonine was isolated. This cell line contains more proteins, peptides and free amino acids than the control line. The amount and relative percentage of free and bound lysine and threonine were especially high in the LT2 line. In the free amino acid pool, the contents of the aspartic and glutamic acids of LT2 were also higher but that of alanine, valine, serine and proline tended to be lower than in the control. The biochemical modifications seem to be more important in the fractions of soluble proteins and free amino acids. This study showed the possibility of selection of overproducing amino acid cell lines in cereals and vegetable plants.Key words: Amino acids, lysine, threonine, cell line selection, sugarcane

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Wang, Xiao Xiao, Tao Chen, and Ji Ping Wang. "Degradation of Synthetic Reactive Dye Wastewater Based on Amine-Functionalized Polyacrylonitrile Fiber." Key Engineering Materials 671 (November 2015): 425–30. http://dx.doi.org/10.4028/www.scientific.net/kem.671.425.

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A series of functional fibers have been prepared by modifying a commercially available polyacrylonitrilefiber (PANF) with polyamines such as ethylenediamine, tetraethylenepentamine and hyperbranched polyethylenimine (HPEI), and then used to coordinate with Fe3+, respectively, to produce Fe-modified PAN fiber complexes. The chemical structures of modified PANFs were verified by Fourier transform infrared spectroscopy (FT-IR). X-ray Diffraction (XRD) characterization showed that the inner crystal region of PANF was damaged during the introduction of amine groups.. Organic elemental analysis results to a certain extent demonstrate the success of modification. The coordination of Fe3+ was verified by Energy Dispersive Spectroscopy (EDS). The Fe-modified PAN fiber complexes were were used to eliminate the color from synthetic reactive dye wastewater (SRDW, including Reactive Red 195, RR 195) under normal conditions. This study presents a valuable route towards wastewater treatment in dyeing and finishing.

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Thuriot, Fabrice. "European Capital of Culture 2028: For Which Identities and Values? French Bids for the Title in 2028." Intercultural Relations 7, no. 2(12) (December 21, 2022): 54–67. http://dx.doi.org/10.12797/rm.02.2022.12.04.

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The general objectives of the European Capitals of Culture are to safeguard and promote the diversity of cultures in Europe and the common features they share, while strengthening the sense of belonging to a common cultural space. The growing appeal of the title of European Capital of Culture, especially after the success of Lille (2004) and Marseille (2013), both in France, has led to numerous bids in the country, despite the high cost of preparation and implementation. Amiens, Bastia, Bourges, Clermont-Ferrand, Lens-Lievin, Nice, Reims, Roubaix, Rouen and Saint-Denis have already announced their candidacy to the title of European Capital of Culture in 2028, often in connection with their region. The article analyses the cultural and development projects of these cities and territories according to the criteria of European values and identities.

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Thurston, Alana M., Lauren Waller, Leo Condron, and Amanda Black. "Sensitivity of the soil-borne pathogen Phytophthora agathidicida, the causal agent of kauri dieback, to the anti-oomycete fungicides ethaboxam, fluopicolide, mandipropamid, and oxathiapiprolin." New Zealand Plant Protection 75 (May 3, 2022): 14–18. http://dx.doi.org/10.30843/nzpp.2022.75.11751.

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The oomycete Phytophthora agathidicida is the causal agent of kauri dieback, which threatens the survival of endemic kauri (Agathis australis) forests in Aotearoa|New Zealand. Current chemical control of P. agathidicida involves the application of either a mixture of halogenated tertiary amines or phosphite salts with some success, but neither treatment cures the disease. Recently, four anti-oomycete fungicides, all with different modes of action, have become commercially available. Here, we determined the inhibition potential of these fungicides on three P. agathidicida isolates, using agar dilution assays. The average concentration required to inhibit mycelial growth by 50% (EC50) for ethaboxam, fluopicolide, and mandipropamid was 0.0916, 0.372, and 0.0196 µg/mL, respectively. Inhibition of P. agathidicida mycelia by oxathiapiprolin and its commercial formulation, Zorvec® Enicade®, was 0.000152 and 0.000309 µg/mL, respectively. Based on the EC50 values reported in this study, these fungicides are the most effective inhibitors of P. agathidicida mycelia when compared to previously screened fungicides, natural products, and plant extracts. Thus, their performance in this initial screening supports further research into their potential use as a kauri dieback management tool.

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Michael Besser, G., Ronald F. Pfeiffer, and Michael O. Thorner. "ANNIVERSARY REVIEW: 50 years since the discovery of bromocriptine." European Journal of Endocrinology 179, no. 2 (August 2018): R69—R75. http://dx.doi.org/10.1530/eje-18-0378.

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Ergotism is the long-term ergot poisoning by ingestion of rye or other grains infected with the fungus Claviceps purpurea and more recently by excessive intake of ergot drugs. It has either neuropsychiatric or vascular manifestations. In the Middle Ages, the gangrenous poisoning was known as St. Anthony’s fire, after the order of the Monks of St. Anthony who were particularly skilled at treating the condition. In 1917, Prof. Arthur Stoll returned home to Switzerland from Germany, to lead the development of a new pharmaceutical department at Sandoz Chemical Company. Stoll, using the special methods of extraction learned from his work with his mentor Willstetter, started his industrial research work with ergot. He succeeded in isolating, from the ergot of rye, ergotamine as an active principle of an old popular remedy for excessive post-partum bleeding. The success of this discovery occurred in 1918 and was translated into a pharmaceutical product in 1921 under the trade name Gynergen. In subsequent work, Stoll and his team were leaders in identifying the structure of the many other alkaloids and amines produced by Claviceps purpurea. This was the cultural background and scientific foundation on which bromocriptine was discovered.

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Varga, Petra R., and György Keglevich. "Synthesis of α-Aminophosphonates and Related Derivatives; The Last Decade of the Kabachnik–Fields Reaction." Molecules 26, no. 9 (April 25, 2021): 2511. http://dx.doi.org/10.3390/molecules26092511.

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The Kabachnik–Fields reaction, comprising the condensation of an amine, oxo compound and a P-reagent (generally a >P(O)H species or trialkyl phosphite), still attracts interest due to the challenging synthetic procedures and the potential biological activity of the resulting α-aminophosphonic derivatives. Following the success of the first part (Molecules 2012, 17, 12821), here we summarize the synthetic developments in this field accumulated in the last decade. The procedures compiled include catalytic accomplishments as well as catalyst-free and/or solvent-free “greener” protocols. The products embrace α-aminophosphonates, α-aminophosphinates, and α-aminophosphine oxides along with different bis derivatives from the double phospha-Mannich approach. The newer developments of the aza-Pudovik reactions are also included.

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Zimuwandeyi, Memory, Manuel A. Fernandes, Amanda L. Rousseau, and Moira L. Bode. "Total synthesis of ent-pavettamine." Beilstein Journal of Organic Chemistry 17 (June 10, 2021): 1440–46. http://dx.doi.org/10.3762/bjoc.17.99.

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Pavettamine, a plant toxin first isolated from Pavetta harborii in 1995, was previously identified as a polyamine with C2 symmetry and a 1,3-syn-diol moiety on a C10 carbon backbone – one of very few substituted polyamines to be isolated from nature. Its absolute configuration was later established by our first reported total synthesis in 2010. Herein we report the first total synthesis of the enantiomer of pavettamine, ent-pavettamine. The symmetrical structure of the molecule allows for the synthesis of a common C5 fragment that can be divergently transformed into two synthons for later convergent coupling to furnish the target carbon framework. Based on the success of the protocol we employed for the synthesis of the naturally occurring pavettamine, (S)-malic acid was again the starting material of choice for the synthesis of the two individual C5 fragments, with strategic differences in terminal-group manipulation allowing for the synthesis of ent-pavettamine rather than pavettamine. Chain extension and stereoselective ketone reduction were achieved using the (R)-methyl p-tolyl sulfoxide chiral auxiliary to give the desired 1,3-syn-diol C5 unit. A protecting-group strategy was also developed for the orthogonal protection of the alcohol and amine functional groups as they were unveiled. The functionalized C5 fragments were coupled via reductive amination revealing the C10 carbon backbone. Deprotection of the alcohol and amine functional groups successfully provided ent-pavettamine as a TFA salt.

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Bachrach, Uriel. "Polyamines and carcinogenesis." Acta Facultatis Medicae Naissensis 29, no. 4 (December 1, 2012): 165–74. http://dx.doi.org/10.2478/v10283-012-0023-5.

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SUMMARY The naturally occurring polyamines, spermine, spermidine and the diamine putrescine are widespread in nature. They have been implicated in growth and differentiation processes. In 1967, we reported that cancer cells are rich in polyamines. Subsequently, it has been shown that polyamines are released from cancer cells and may be detected in body fluids such as urine, blood and cerebrospinal fluids. It has also been demonstrated that the increase in cellular polyamine levels is an early and an obligatory event in the process of malignant transformation. This increase in cellular polyamine concentration is due to the activation of ornithine decarboxylase (ODC), which catalyses the rate limiting step in polyamine synthesis by converting ornithine to putrescine. Assays of urinary and blood polyamines have been used to detect cancer and to determine the success of therapy. A sensitive, rapid, chemiluminescence-based method for the determination of diamines and polyamines was developed and 2.000 urine samples were tested. An interesting "gene therapy" system for injecting amine oxidases into normal and transformed cells was developed as follows: serum amine oxidase and porcine kidney damine oxidase were trapped within reconstituted Sendai virus envelopes. Chick or rat fibroblasts, transformed by Rous sarcoma virus, were more susceptible to the injected enzymes, compared to the normal culture, when macromolecular synthesis was tested. An in vitro chemosensitivity assay for the testing of the sensitivity of cancer cells from individual patients ("tailored treatment") was also developed. All these studies stress the importance of polyamines in carcinogenesis.

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Wang, Chunyan, Jianping Xu, Junxin Yang, Yong Qian, and Hesheng Liu. "In-situ polymerization and multifunctional properties of surface-modified multiwalled carbon nanotube-reinforced polyimide nanocomposites." High Performance Polymers 29, no. 7 (July 12, 2016): 797–807. http://dx.doi.org/10.1177/0954008316657862.

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In this study, strong multiwalled carbon nanotube (MWNT)–polyimide (PI) matrix interfaces were designed and constructed to obtain high-performance nanocomposites via in-situ polymerization. MWNTs with reactive amino groups were produced by the covalent linking of phenylenediamine to the surface of MWNTs by amide bonds; this material exhibited excellent dispersibility and compatibility with the PI matrix. The incorporation of amine-functionalized MWNT (MWNT-NH2) significantly improved the macroscopic properties of the PI-based nanocomposites. A 50.5% increase in the tensile strength and an 83.1% increase in the Young’s modulus were achieved by 3.0 wt% MWNT-NH2 loading. Furthermore, the storage modulus, thermal stability, and glass transition temperature of the nanocomposite clearly increased by adding MWNT-NH2. The success of this method provides a good rational for developing high-performance polymer-based nanocomposites.

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Journal articles on the topic 'Sucres amines'

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