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    Wyświetlanie 1-10 z 10
    Tytuł:
    To treat or not to treat drug-refractory epilepsy by the ketogenic diet? That is the question
    Autorzy:
    Ułamek-Kozioł, Marzena
    Pluta, Ryszard
    Bogucka-Kocka, Anna
    Czuczwar, Stanisław J.
    Powiązania:
    https://bibliotekanauki.pl/articles/989609.pdf
    Data publikacji:
    2016
    Wydawca:
    Instytut Medycyny Wsi
    Tematy:
    ketogenic diet
    ketones
    acetone
    epilepsy
    antiepileptic drugs
    Opis:
    Epilepsy is a serious neurologic disorder worldwide which affects about 1% of the population (ca. 50 million people), the highest prevalence occurring in both children and elderly. Apart from idiopathic forms, etiology of the disease involves multiple brain risk factors – the most frequent being cerebrovascular diseases, tumours and traumatic injuries. Several treatment options exist, including, for instance, pharmacotherapy, vagal nerve stimulation or epilepsy surgery. In spite of treatment, about 30% of patients with epilepsy still have seizures and become drug-refractory. This is why other treatment options may be recommended, and ketogenic diet seems a last-chance method, especially in children and adolescents with epilepsy. The diet contains high amounts of fat and low carbohydrates with vitamin supplementation. The elevated concentrations of ketones induced by the diet may result in inhibition of the synaptic activity of glutamate, the mammalian target of the rapamycin pathway, and activation of adenosine triphosphate-sensitive potassium channels. One of the main ketones is acetone, shown to increase the seizure threshold and potentiate the anticonvulsant activity of some antiepileptic drugs. The clinical effectiveness of the ketogenic diet has been confirmed in a number of clinical trials carried out mainly on children. A wider use of the ketogenic diet may be limited by the number of early adverse effects (gastrointestinal distress, acidosis, hypoglycaemia, dehydration and lethargy), and late adverse effects (hyperuricaemia, hyperlipidaemia, kidney stones, easy bruising, and decreases in height and weight). Recently, data are available on the negative impact of the ketogenic diet on the qualitative characteristics of lipoprotein subfractions which points to the atherogenic fenotype as a new side-effect. In conclusion, future research directed to the proper identification of patients (in terms of age, epilepsy type and duration, recommended antiepileptic drugs) is necessary to answer the title question.
    Źródło:
    Annals of Agricultural and Environmental Medicine; 2016, 23, 4
    1232-1966
    Pojawia się w:
    Annals of Agricultural and Environmental Medicine
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Oxidation of cyclic ketones to dicarboxylic acids
    Autorzy:
    Lisicki, D.
    Orlińska, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/779941.pdf
    Data publikacji:
    2018
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    Dicarboxylic acids
    cyclic ketones
    oxidation
    cyclopentanone
    glutaric acid
    Opis:
    This paper reports the results of studies concerning an alternative method of obtaining dicarboxylic acids, which consist of the oxidation of cyclic ketones with oxygen or air. The raw materials used were cyclopentanone, cycloheptanone, cyclooctanone, cyclododecanone, 1-tetralon, 2-methylhexanone, 3-methylcyclohexanone and 4-methylcyclohexanone. Oxidation reactions were conducted at 70-100°C, under pressure of 0.1 or 0.4 MPa, for 6 h, utilizing the salts of transition metals as catalyst and acetic acid as solvent. For example, when cyclopentanone was oxidized in the presence of Mn(II) salt, a conversion above 98% and selectivity to glutaric acid up to 68% were obtained. Among synthesized dicarboxylic acids, 1,12-dodecanoic acid was obtained with the highest selectivity of 76%.
    Źródło:
    Polish Journal of Chemical Technology; 2018, 20, 4; 102-107
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Generating Organic Compounds by Retrosynthetic Pathway via Typical Corey’s Synthesis
    Autorzy:
    Ononiwu, Chinonso Godwin
    Enwereuzo, Onyekachi Oluchi
    Akakuru, Obinna Chigoziem
    Ejiogu, Chukwudima Benaiah
    Onumah, Chinonso Uchenna
    Achukee, Chinedu Kingsley
    Umaefulam, Tobechukwu Nnamdi
    Abaekwume, Nkechi Nancy
    Akakuru, Ozioma Udochukwu
    Powiązania:
    https://bibliotekanauki.pl/articles/1031449.pdf
    Data publikacji:
    2021
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Corey’s synthesis
    aldehydes
    alkanes
    alkynes
    ketones
    organic compounds
    organic reaction mechanism
    Opis:
    Several methods exist for the synthesis of alkanes including Corey’s synthesis, Wurtz reaction, reduction of alcohols and aldehydes, Kolbe’s electrolysis, hydrogenation of alkenes, and Grignard reaction. Among the available methods, the age-long Corey’s synthesis presents robust advantages of yielding symmetrical, unsymmetrical, straight chain and branched chain alkanes. Moreover, it allows of generating high yields of alkanes by utilizing primary alkyl halide and an array of lithium dialkyl copper ranging from primary, secondary to tertiary. Corey’s synthesis has also been implicated in the synthesis of various organic compounds such as (+)-taylorione, terminal alkynes, caribenol A, ketones, and aldehydes. In this work, an explanation of the general concept in the Corey’s synthesis is provided. Furthermore, specific examples of Corey’s reactions and modifications are discussed. Finally, an outlook into the benefits of the Corey’s synthesis in present-day organic synthesis is provided, which is expected to enhance the understanding of organic reaction mechanisms for the development of various organic compounds as drugs for treating diseases.
    Źródło:
    World News of Natural Sciences; 2021, 36; 88-98
    2543-5426
    Pojawia się w:
    World News of Natural Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spectral correlations and antimicrobial activities of some 1-pyrenyl chalcones
    Autorzy:
    Arulkumaran, R.
    Vijayakumar, S.
    Sundararajan, R.
    Sakthinathan, S.P.
    Kamalakkannan, D.
    Suresh, R.
    Ranganathan, K.
    Rajakumar, P.R.
    Powiązania:
    https://bibliotekanauki.pl/articles/411776.pdf
    Data publikacji:
    2013
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    substituted styryl 1-pyrenyl ketones
    UV spectra
    IR spectra
    NMR spectra
    substituent effects
    antimicrobial activities
    Opis:
    A series of 1-pyrenyl chalcones have been synthesized by Crossed-Aldol condensation of 1-acetylpyrene and substituted benzaldehydes. The purities of these chalcones have been checked by their physical constants, UV, IR, NMR and MASS spectral data. The spectral data of these chalcones have been correlated with Hammett sigma constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the spectral group frequencies have been discussed. The anti-microbial activities of these chalcones have been evaluated using Bauer-Kirby method.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2013, 5; 21-38
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Insect antifeedant potent halogen substituted phenyl chalcones
    Autorzy:
    Sundararajan, R.
    Arulkumaran, R.
    Vijayakumar, S.
    Kamalakkannan, D.
    Suresh, R.
    John, J. S.
    Ranganathan, K.
    Sakthinathan, S. P
    Vanangamudi, G.
    Thirunarayanan, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/412081.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Substituted styryl 2′,3′,4′-trichlorophenyl ketones
    sulfated Titania
    IR and NMR spectra
    Insect antifeedant activities
    Opis:
    Some 2′,3′,4′-trichlorophenyl chalcones [(E)-1-(2,3,4-trichlorophenyl)-3-(substituted phenyl)-2-propen-1-ones] have been synthesised using sulfated Titania catalyzed solvent-free aldol condensation between 2,3,4-trichloroacetophenone and substituted benzaldehydes. The purities of synthesised chalcones were checked by their analytical, physical and spectroscopic data reported in literature. The insect antifeedant activities of these chalcones have been studied using 4th instar larvae Achoea Janata L by castor leaf disc bio-assay method. The chloro substituted chalcones shows significant insect antifeedant activity.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 1; 67-73
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spectral correlation analysis and antimicrobial activities of some 2,4-dimethoxy phenyl chalcones
    Autorzy:
    Joseph, S. J.
    Arulkumaran, R.
    Kamalakkannan, D.
    Sakthinathan, S. P.
    Sundararajan, R.
    Suresh, R.
    Vijayakumar, S.
    Ranganathan, K.
    Kalyanasundaram, N.
    Vanangamudi, G.
    Thirunarayanan, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/412661.pdf
    Data publikacji:
    2014
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    substituted styryl 2
    4-dimethoxy phenyl ketones
    UV spectra
    IR spectra
    NMR spectra
    substituent effects
    antimicrobial activities
    Opis:
    A series of 2,4-dimethoxy phenyl chalcones have been synthesized by Crossed-Aldol condensation of 2,4-dimethoxy phenyl and various substituted benzaldehydes. The purities of these chalcones have been checked by their physical constants, UV, IR, NMR and MASS spectral data. The spectral data of these chalcones have been correlated with Hammett sigma constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effects of substituents on the spectral group frequencies have been discussed. The anti-microbial activities of these chalcones have been evaluated using Bauer-Kirby method.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2014, 4; 48-65
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Enzymatyczne reakcje rozszczepienia wiązania C–C : zastosowanie w syntezie związków zapachowych, farmaceutyków oraz w bioremediacji
    Enzymatic reactions of the C–C bond cleavage : applications in synthesis of aroma compounds, pharmaceuticals and in bioremediation
    Autorzy:
    Panek, A.
    Milecka-Tronina, N.
    Świzdor, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/172055.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    β-oksydacja
    wanilina
    γ-dekalakton
    metyloketony
    leki steroidowe
    bioremediacja
    β-oxidation
    vanillin
    γ-decalactone
    methyl ketones
    steroid drugs
    bioremediation
    Opis:
    The microorganisms are able to utilize natural and synthetic compounds of broad structural diversity as a source of carbon and energy, converting these substrates into low molecular weight products (mainly H2O, CO2 and NH3). The main role in this metabolism is played by the enzymes that catalyze reactions of the C–C bond cleavage. Such reactions are the key step of the primary metabolism of fatty acids in eukaryotic cells by the β-oxidation. The enzymatic systems associated with the C–C bond cleavage have been applied in the synthesis of valuable natural products and in the bioremediation processes. Microbial transformations of natural compounds, in which the reactions of β-oxidation cycle are used, allow the formation of natural aromatic compounds (used as food additives), pharmaceuticals and ingredients of cosmetic compositions. Using this path one can obtain methyl ketones (e.g. responsible for the characteristic smell of cheeses), γ-lactones determining the scent of several popular fruits, and vanillin. A modification of the natural steroids: saponins, alkaloids, sterols, bile acids to products useful in the synthesis of steroid drugs is the most important area of use of the enzymatic C–C bond cleavage, due to the practical significance of the products. Enzymes that catalyze the C–C bonds cleavage are important in the process of biodegradation of toxic aromatic hydrocarbons and their derivatives (bioremediation).
    Źródło:
    Wiadomości Chemiczne; 2015, 69, 5-6; 337-368
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A study of ruthenium-based catalysts used in homogeneous transfer hydrogenation of acetophenone
    Autorzy:
    Mikołajczyk, Filip
    Kamiński, Kamil
    Powiązania:
    https://bibliotekanauki.pl/articles/185307.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ruthenium-based catalysts
    transfer hydrogenation
    ketones
    catalysis
    RuCl2(PPh3)3
    katalizatory na bazie rutenu
    przeniesienie uwodornienia
    ketony
    kataliza
    RuCl2 (PPh3) 3
    Opis:
    A detailed comparison of catalytic properties of two different ruthenium-based catalysts in the reaction of homogeneous hydrogenation of acetophenone was performed. Additionally, methods of synthesis of both catalysts were tested and optimized in order to achieve the best possible quality and purity of the final catalysts. NMR analysis was used to analyze and identify the composition of ruthenium compounds and gas chromatography was used to analyze the conversion rate of hydrogenation reactions. It was determined that RuCl2(PPh3)3 obtained with a modified method described by Shaw’s group (Shawet al., 2007) had the best catalytic properties in the reaction performed under conditions described in Liang Wang’s publication (Wang et al., 2014). It was also determined that for concentration ratio of substrate to RuCl2(PPh3)3 amounting to 250:1 the conversion rate was much higher than that of the reaction performed with a double dose of the catalyst. Results of experiments also show that samples of the post-reaction solution should be analyzed right after the reaction, because even if they are stored in low temperature the amount of product can change up to 3–5% compared to the base sample and this change is not predictable. These findings have significant implications for further research of the reaction of homogeneous transfer hydrogenation of ketones. With the right catalysts and methods of their synthesis other parameters of this reaction can be optimized. The most important one is a change of solvent from isopropyl alcohol to a less toxic substance like water. This may increase the value of the reaction in green chemistry and chemical industry.
    Źródło:
    Chemical and Process Engineering; 2019, 40, 2; 213--222
    0208-6425
    2300-1925
    Pojawia się w:
    Chemical and Process Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dwie dekady chemo-enzymatycznej reakcji Baeyera-Villigera
    Two decades of chemo-enzymatic Baeyer-Villiger reaction
    Autorzy:
    Drożdż, A.
    Bielas, R.
    Chrobok, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/171768.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    reakcja Baeyera-Villigera
    chemo-enzymatyczna reakcja Baeyera-Villigera
    laktony
    utlenianie cyklicznych ketonów
    lipaza B Candida antarctica
    chemo-enzymatic Baeyer–Villiger reaction
    lactones
    cyclic ketones oxidation
    lipase B Candida antarctica
    Opis:
    The Baeyer–Villiger oxidation of ketones to lactones or esters is a reaction of significant interest in organic chemistry owing to very wide range of possible applications, e.g. in the synthesis of antibiotics, steroids, pheromones and monomers for polymerisation. The organic percarboxylic acids typically used as oxidants in these reactions are fairly expensive, often poorly stable and hazardous, and this consequently limits their commercial application. Therefore, the chemo-enzymatic approach appears to be a very attractive alternative. The paper presents literature reports concerning the application the use of lipase B from Candida antarctica in the chemo-enzymatic Baeyer-Villiger oxidation. It involves oxidation of long- or medium-chain carboxylic acids with H2O2 or urea hydrogen peroxide to generate in situ peracid which is later used to oxidise ketones to lactones.
    Źródło:
    Wiadomości Chemiczne; 2014, 68, 11-12; 1031-1048
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thionylchloride catalyzed aldol condensation: Synthesis, spectral correlation and antibacterial activities of some 3,5-dichloro-2-hydroxyphenyl chalcones
    Autorzy:
    Arulkumaran, R.
    Vijayakumar, S.
    Sundararajan, R.
    Sakthinathan, S. P.
    Kamalakkannan, D.
    Suresh, R.
    Ranganathan, K.
    Vanangamudi, G.
    Thirunarayanan, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/411825.pdf
    Data publikacji:
    2012
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    chlorek tionylu
    widma IR i NMR
    korelacja Hammeta
    aktywność antybakteryjna
    wpływ podstawników
    styrylo 3,5-dichloro-2-hydroksy fenylo ketony
    thionyl chloride
    styryl 3,5-dichloro-2-hydroxyphenyl ketones
    IR and NMR spectra
    Hammett correlation
    substituent effects
    antimicrobial activities
    Opis:
    A series of substituted styryl 3,5-dichloro-2-hydroxyphenyl ketones [1-(3, 5-dichloro-2-hydroxy)- 3-phenylprop-2-en-1-one] were synthesized using thionyl chloride assisted Crossed Aldol reaction. The yields of chalcones were more than 80%. The synthesized chalcones were characterized by analytical and spectroscopic data. From the spectroscopic data the group frequencies were correlated with Hammett substituent constants, F and R parameters. From the results of statistical analysis the effect of substituents were discussed. The antibacterial activities of these chalcones have been evaluated using Bauer-Kirby method.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2012, 4; 17-38
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-10 z 10

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