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  1. Article: Lewis-Acid-Catalyzed (3+2)-Cycloadditions of Donor-Acceptor Cyclopropanes with Thioketenes.

    Mlostoń, Grzegorz / Kowalczyk, Mateusz / Augustin, André U / Jones, Peter G / Werz, Daniel B

    European journal of organic chemistry

    2021  Volume 2021, Issue 46, Page(s) 6250–6253

    Abstract: The reactivity of donor-acceptor (D-A) cyclopropanes towards thioketenes was investigated. In a (3+2)-cycloaddition using Sc(OTf) ...

    Abstract The reactivity of donor-acceptor (D-A) cyclopropanes towards thioketenes was investigated. In a (3+2)-cycloaddition using Sc(OTf)
    Language English
    Publishing date 2021-08-25
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1475010-7
    ISSN 1099-0690 ; 1434-193X
    ISSN (online) 1099-0690
    ISSN 1434-193X
    DOI 10.1002/ejoc.202100879
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Hexamethylenetetramine Complexes as Easy-to-Handle and Efficient Lewis Acid–Base Heterogeneous Catalysts for Coupling of CO₂ under Mild Conditions

    Lan, Dong-Hui / Chen, Kun / Zhu, Heng-Jun / Shen, Jing / Wu, Shui-Sheng / Au, Chak-Tong / Yi, Bing / Yin, ShuangFeng

    Industrial & engineering chemistry process design and development. 2022 July 23, v. 61, no. 31

    2022  

    Abstract: In terms of the multisynergetic effects among Lewis acid, halogen anions, and Lewis base, a series ... of Lewis acid–base hexamethylenetetramine complexes with tertiary amines, different metal centers, and halogen ... in nucleophilicity and Lewis acidity are designed and evaluated, which suggest that the stronger Lewis acidity ...

    Abstract In terms of the multisynergetic effects among Lewis acid, halogen anions, and Lewis base, a series of Lewis acid–base hexamethylenetetramine complexes with tertiary amines, different metal centers, and halogen anions were conveniently synthesized at room temperature. Hexamethylenetetramine is cheap, nontoxic, rich in tertiary amine, and with a cage structure. This is the first time that the hexamethylenetetramine complexes were used as efficient and stable heterogeneous catalysts for the generation of cyclic carbonates by the coupling reaction of CO₂ under relatively mild conditions (60 °C, 1.5 MPa, 12 h) with outstanding performance (yield = 98.9%) without use of solvent and cocatalyst. Hatm complexes that are different in nucleophilicity and Lewis acidity are designed and evaluated, which suggest that the stronger Lewis acidity of metal together with stronger nucleophilicity of anions means higher catalytic performance. A plausible multisynergetic mechanism over ZnBr₂–Hatm is proposed for the CO₂ coupling. In addition, the ZnBr₂–Hatm can be conveniently recovered and reused in a test of five times without remarkable decline of activity.
    Keywords Lewis acids ; Lewis bases ; acidity ; ambient temperature ; carbon dioxide ; catalytic activity ; chemical structure ; halogens ; process design ; solvents
    Language English
    Dates of publication 2022-0723
    Size p. 11390-11396.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 1484436-9
    ISSN 1520-5045 ; 0888-5885
    ISSN (online) 1520-5045
    ISSN 0888-5885
    DOI 10.1021/acs.iecr.2c00254
    Database NAL-Catalogue (AGRICOLA)

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  3. Article ; Online: Formal Insertion of Thioketenes into Donor-Acceptor Cyclopropanes by Lewis Acid Catalysis.

    Augustin, André U / Busse, Marius / Jones, Peter G / Werz, Daniel B

    Organic letters

    2018  Volume 20, Issue 3, Page(s) 820–823

    Abstract: Donor-acceptor cyclopropanes were reacted under Lewis acid catalysis with 3-thioxocyclobutanones ...

    Abstract Donor-acceptor cyclopropanes were reacted under Lewis acid catalysis with 3-thioxocyclobutanones as surrogates for disubstituted thioketenes. A broad scope of 2-substituted tetrahydrothiophenes with a semicyclic double bond was obtained under mild conditions with high functional group tolerance and in excellent yield. A sequence of a formal [3 + 2]-cycloaddition followed by the subsequent release of disubstituted ketene is postulated as the mechanism.
    Language English
    Publishing date 2018--02
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1523-7052
    ISSN (online) 1523-7052
    DOI 10.1021/acs.orglett.7b03961
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Book ; Thesis: Stereologische Untersuchungen zur Auswirkung maternaler Deprivation auf die Entwicklung von Neuronen in Gyrus dentatus und Hippokampus bei Fischer 344- und Lewis-Ratten

    Niesel-Willenborg, Alexandra Ulrike

    2005  

    Author's details vorgelegt von Alexandra Ulrike Niesel-Willenborg geb. Niesel
    Language German
    Size III, 75 S. : Ill., graph. Darst.
    Publishing country Germany
    Document type Book ; Thesis
    Thesis / German Habilitation thesis Aachen, Techn. Hochsch., Diss., 2005
    HBZ-ID HT014678660
    Database Catalogue ZB MED Medicine, Health

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    In stock of ZB MED Cologne/Königswinter

    Shelf markLoan statusLocation
    2006 D 126 order for loan Magazin

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  5. Article: Formal Insertion of Thioketenes into Donor–Acceptor Cyclopropanes by Lewis Acid Catalysis

    Augustin, André U / Daniel B. Werz / Marius Busse / Peter G. Jones

    Organic letters. 2018 Feb. 02, v. 20, no. 3

    2018  

    Abstract: Donor–acceptor cyclopropanes were reacted under Lewis acid catalysis with 3-thioxocyclobutanones ...

    Abstract Donor–acceptor cyclopropanes were reacted under Lewis acid catalysis with 3-thioxocyclobutanones as surrogates for disubstituted thioketenes. A broad scope of 2-substituted tetrahydrothiophenes with a semicyclic double bond was obtained under mild conditions with high functional group tolerance and in excellent yield. A sequence of a formal [3 + 2]-cycloaddition followed by the subsequent release of disubstituted ketene is postulated as the mechanism.
    Keywords catalytic activity ; chemical bonding ; chemical reactions ; Lewis acids ; moieties ; organic compounds
    Language English
    Dates of publication 2018-0202
    Size p. 820-823.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1523-7052
    DOI 10.1021/acs.orglett.7b03961
    Database NAL-Catalogue (AGRICOLA)

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  6. Article ; Online: Establishing the correlation between catalytic performance and N→Sb donor-acceptor interaction: systematic assessment of azastibocine halide derivatives as water tolerant Lewis acids.

    Lei, Jian / Peng, Lingteng / Qiu, Renhua / Liu, Yongping / Chen, Yi / Au, Chak-Tong / Yin, Shuang-Feng

    Dalton transactions (Cambridge, England : 2003)

    2019  Volume 48, Issue 23, Page(s) 8478–8487

    Abstract: ... framework were synthesized and employed as water tolerant Lewis acid catalysts. The results of a systematic ...

    Abstract A series of organoantimony(iii) halide complexes with a tetrahydrodibenzo[c,f][1,5]azastibocine framework were synthesized and employed as water tolerant Lewis acid catalysts. The results of a systematic structure-activity relationship study demonstrated that the strength of N→Sb donor-acceptor interaction could be synergistically modulated by tuning the properties of the nitrogen substituents and halogen atoms adjacent to the central antimony atom, and consequently resulted in distinct catalytic performances towards organic reactions such as Mannich, cross-condensation, cyclization-aromatization and epoxide aminolysis reaction. The fluorinated organoantimony(iii) derivatives were found to be more active than those of the chlorinated, brominated and iodinated analogues, owing to the use of an Sb-F moiety as a hydrogen bond acceptor. By comparison, the compound 6-cyclohexyl-12-fluoro-5,6,7,12-tetrahydrodibenzo[c,f][1,5] azastibocine (1d) is found to exhibit the highest catalytic activity, together with facile reusability in scale enlarged synthesis.
    Language English
    Publishing date 2019-05-22
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472887-4
    ISSN 1477-9234 ; 1364-5447 ; 0300-9246 ; 1477-9226
    ISSN (online) 1477-9234 ; 1364-5447
    ISSN 0300-9246 ; 1477-9226
    DOI 10.1039/c9dt01100e
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Reactions of Donor-Acceptor Cyclopropanes with Naphthoquinones: Redox and Lewis Acid Catalysis Working in Concert.

    Lücht, Alexander / Patalag, Lukas J / Augustin, André U / Jones, Peter G / Werz, Daniel B

    Angewandte Chemie (International ed. in English)

    2017  Volume 56, Issue 35, Page(s) 10587–10591

    Abstract: Reactions of 2-arylcyclopropane dicarboxylates with naphthoquinones are reported. The key feature was the use of catalytic amounts of ... ...

    Abstract Reactions of 2-arylcyclopropane dicarboxylates with naphthoquinones are reported. The key feature was the use of catalytic amounts of SnCl
    Language English
    Publishing date 2017-07-19
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2011836-3
    ISSN 1521-3773 ; 1433-7851
    ISSN (online) 1521-3773
    ISSN 1433-7851
    DOI 10.1002/anie.201703732
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  8. Article ; Online: Low Band Gap Coplanar Conjugated Molecules Featuring Dynamic Intramolecular Lewis Acid-Base Coordination.

    Zhu, Congzhi / Guo, Zi-Hao / Mu, Anthony U / Liu, Yi / Wheeler, Steven E / Fang, Lei

    The Journal of organic chemistry

    2016  Volume 81, Issue 10, Page(s) 4347–4352

    Abstract: ... of the optical properties of these molecules by using competing Lewis basic solvents. ...

    Abstract Ladder-type conjugated molecules with a low band gap and low LUMO level were synthesized through an N-directed borylation reaction of pyrazine-derived donor-acceptor-donor precursors. The intramolecular boron-nitrogen coordination bonds played a key role in rendering the rigid and coplanar conformation of these molecules and their corresponding electronic structures. Experimental investigation and theoretical simulation revealed the dynamic nature of such coordination, which allowed for active manipulation of the optical properties of these molecules by using competing Lewis basic solvents.
    Language English
    Publishing date 2016-05-20
    Publishing country United States
    Document type Journal Article
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.6b00238
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 4473: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

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  9. Article: The MEK-Inhibitor Selumetinib Attenuates Tumor Growth and Reduces IL-6 Expression but Does Not Protect against Muscle Wasting in Lewis Lung Cancer Cachexia.

    Au, Ernie D / Desai, Aditya P / Koniaris, Leonidas G / Zimmers, Teresa A

    Frontiers in physiology

    2017  Volume 7, Page(s) 682

    Abstract: Cachexia, or wasting of skeletal muscle and fat, afflicts many patients with chronic diseases including cancer, organ failure, and AIDS. Muscle wasting reduces quality of life and decreases response to therapy. Cachexia is caused partly by elevated ... ...

    Abstract Cachexia, or wasting of skeletal muscle and fat, afflicts many patients with chronic diseases including cancer, organ failure, and AIDS. Muscle wasting reduces quality of life and decreases response to therapy. Cachexia is caused partly by elevated inflammatory cytokines, including interleukin-6 (IL-6). Others and we have shown that IL-6 alone is sufficient to induce cachexia both
    Language English
    Publishing date 2017-01-18
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2564217-0
    ISSN 1664-042X
    ISSN 1664-042X
    DOI 10.3389/fphys.2016.00682
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  10. Article: A mini-review on air-stable organometallic Lewis acids: synthesis, characterization, and catalytic application in organic synthesis

    Qiu, Renhua / Chen, Yi / Yin, Shuang-Feng / Xu, Xinhua / Au, Chak-Tong

    RSC advances. 2012 Oct. 22, v. 2, no. 29

    2012  

    Abstract: Organometallic Lewis acids play an important role in modern organic synthesis. How to design and ... synthesize highly efficient and recyclable organometallic Lewis acid catalysts that can be conveniently ... acidity means higher catalytic activity for organometallic Lewis acids. However, with the rise in acidity ...

    Abstract Organometallic Lewis acids play an important role in modern organic synthesis. How to design and synthesize highly efficient and recyclable organometallic Lewis acid catalysts that can be conveniently applied in chemical reactions are key issues for sustainable synthetic processes. In general, stronger acidity means higher catalytic activity for organometallic Lewis acids. However, with the rise in acidity, the compound becomes more susceptible to hydrolysis and cannot be recycled. Simultaneous improvement of the hygroscopic character and Lewis acidity/catalytic activity of organometallic Lewis acids is highly desirable from the standpoint of practical applications. In this mini-review, the history of air-stable organometallic Lewis acids is introduced, with emphasis on our research works on metallocene, organobismuth, and organoantimony Lewis acids to the aspects of synthesis, characterization and catalytic application in carbon–carbon bond (Friedel–Crafts acylation, Mukaiyama aldol reactions; allylation, cyclotrimerization, Mannich reactions, cross-condensation reactions) and carbon–heteroatom bond (acylation, S–S bond cleavage, glycosylation) formation reactions. In terms of stability, storage, versatile ability, high catalytic activity and chemo-/stereo-selectivity, the complexes will find broad applications in organic synthesis.
    Keywords Lewis acids ; acidity ; acylation ; allylation ; catalysts ; catalytic activity ; chemical bonding ; cleavage (chemistry) ; glycosylation ; hydrolysis
    Language English
    Dates of publication 2012-1022
    Size p. 10774-10793.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ISSN 2046-2069
    DOI 10.1039/c2ra21517a
    Database NAL-Catalogue (AGRICOLA)

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