LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 4 of total 4

Search options

  1. Article: Enamine Organocatalysts for the Thiol-Michael Addition Reaction and Cross-Linking Polymerizations

    Sinha, Jasmine / Soars, Shafer / Bowman, Christopher N

    Macromolecules. 2021 Feb. 02, v. 54, no. 4

    2021  

    Abstract: This article describes an efficient enamine organocatalyzed thiol-Michael click reaction and its broad application in cross-linking polymerizations. A series of enamines was shown to catalyze the thiol-Michael reaction via a nucleophilic pathway. By ... ...

    Abstract This article describes an efficient enamine organocatalyzed thiol-Michael click reaction and its broad application in cross-linking polymerizations. A series of enamines was shown to catalyze the thiol-Michael reaction via a nucleophilic pathway. By varying the amines as well as the ring size of the ketones, enamines were designed with broad ranges of nucleophilic character ranging from 11 to 17 on the Mayr nucleophilicity scale. Upon evaluating the enamines’ organocatalytic effect on the kinetics of reactions involving a thiol and Michael acceptor, wherein butyl 3-mercaptopropionate and 1-hexyl acrylate were used as model reactants, enamines were shown to outperform their base analogs. The efficiency and overall reaction yields, ranging from 11 to 92% based on the thiol conversion, were highly dependent upon the nucleophilicity of the enamines employed. Interestingly, in situ formation of an enamine via photo-deprotection of an amine in the presence of cyclic ketones facilitated the thiol-Michael reaction efficiently while simultaneously enabling higher functional group conversion. This efficiency in the reaction kinetics and conversion was extended to multifunctional derivatives, which resulted in the formation of highly cross-linked polymers.
    Keywords Lewis bases ; catalytic activity ; crosslinking ; enamines ; organocatalysts ; reaction kinetics ; thiols
    Language English
    Dates of publication 2021-0202
    Size p. 1693-1701.
    Publishing place American Chemical Society
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 1491942-4
    ISSN 1520-5835 ; 0024-9297
    ISSN (online) 1520-5835
    ISSN 0024-9297
    DOI 10.1021/acs.macromol.0c02128
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Article: Spatial and Temporal Control of Photomediated Disulfide–Ene and Thiol–Ene Chemistries for Two-Stage Polymerizations

    Soars, Shafer M. / Bongiardina, Nicholas J. / Fairbanks, Benjamin D. / Podgórski, Maciej / Bowman, Christopher N.

    Macromolecules. 2022 Feb. 14, v. 55, no. 5

    2022  

    Abstract: A new strategy is reported for the design and synthesis of high sulfur-containing materials for potential use in covalent adaptable networks and optical materials by combining photomediated thiol–ene- and disulfide–ene-based polymerization reactions. ... ...

    Abstract A new strategy is reported for the design and synthesis of high sulfur-containing materials for potential use in covalent adaptable networks and optical materials by combining photomediated thiol–ene- and disulfide–ene-based polymerization reactions. Taking advantage of the relative reaction rates to differentiate sequentially between the thiol–ene and disulfide–ene conjugations, these reactions were performed semiorthogonally to produce polymer networks of controlled architecture. Kinetic analysis demonstrates that the thiol–ene reaction is approximately 30 times faster than the disulfide–ene reaction, enabling spatial and temporal manipulation of material properties via dual-cure networks and photopatterning. A two-stage polymerization approach was implemented with increases in modulus in the second stage of 2–3 orders of magnitude accompanied by increases in the glass-transition temperature of more than 15 °C. Additionally, the thiol–ene reaction in the presence of a disulfide yields materials capable of simultaneous network development and stress relaxation through dynamic bond exchange during in situ polymerization.
    Keywords disulfides ; glass transition temperature ; kinetics ; polymerization ; polymers ; stress relaxation
    Language English
    Dates of publication 2022-0214
    Size p. 1811-1821.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 1491942-4
    ISSN 1520-5835 ; 0024-9297
    ISSN (online) 1520-5835
    ISSN 0024-9297
    DOI 10.1021/acs.macromol.1c02464
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  3. Article: Photodisulfidation of alkenes with linear disulfides: Reaction scope and kinetics

    Kamps, Joshua T. / Soars, Shafer M. / Bongiardina, Nichloas J. / Fairbanks, Benjamin D. / Bowman, Christopher N.

    Tetrahedron. 2022 Mar. 12, v. 109

    2022  

    Abstract: Thiol-ene and thiol-yne photomediated conjugations have received substantial attention in research and in practice. Herein is presented the photodisulfidation of alkenes based on the radical-mediated 1:1 reaction of a disulfide and a vinyl ether, which ... ...

    Abstract Thiol-ene and thiol-yne photomediated conjugations have received substantial attention in research and in practice. Herein is presented the photodisulfidation of alkenes based on the radical-mediated 1:1 reaction of a disulfide and a vinyl ether, which provides an additional route for the formation of the types of sulfides seen in thiol-ene and thiol-yne polymers. Although similar linkages are formed, this approach starting with disulfides is expected to have benefits over the thiol-ene and thiol-yne reactions including extended shelf life of disulfides compared to thiols, reduced shrinkage stress, and increased refractive index of the resulting materials. It was determined that vinyl ethers were the only alkenes capable of undergoing photodisulfidation under ambient conditions and in reasonable timescales. The reaction between vinyl ethers and disulfides performed well in a variety of solvents providing modest to excellent yields (100% for bis(1-methylacetate) disulfide (DSMA)/triethyleneglycol divinylether (TEGDVE)) for numerous disulfide substrates evaluated. It was determined that the mechanism of the photodisulfidation reaction involves an auto-propagating cycle of thiyl radicals which add into either end of a vinyl ether to form thio-ether and thio-acetal linkages in the final product. Finally, although the reaction rate is slower than that of the thiol-ene reaction, the photodisulfidation reaction proceeds relatively rapidly under the explored conditions.
    Keywords alkenes ; disulfides ; extended shelf life ; refractive index ; shrinkage ; thiols
    Language English
    Dates of publication 2022-0312
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 204285-x
    ISSN 1464-5416 ; 0040-4020 ; 0563-2064
    ISSN (online) 1464-5416
    ISSN 0040-4020 ; 0563-2064
    DOI 10.1016/j.tet.2022.132683
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.B 1076: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 2021: Bestellungen von Artikeln über das Online-Bestellformular
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  4. Article ; Online: Discovery of Novel Small-Molecule Inhibitors of NF-κB Signaling with Antiinflammatory and Anticancer Properties.

    Zhang, Lei / Shi, Lei / Soars, Shafer Myers / Kamps, Joshua / Yin, Hang

    Journal of medicinal chemistry

    2018  Volume 61, Issue 14, Page(s) 5881–5899

    Abstract: Excessive NF-κB activation contributes to the pathogenesis of numerous diseases. Small-molecule inhibitors of NF-κB signaling have significant therapeutic potential especially in treating inflammatory diseases and cancers. In this study, we performed a ... ...

    Abstract Excessive NF-κB activation contributes to the pathogenesis of numerous diseases. Small-molecule inhibitors of NF-κB signaling have significant therapeutic potential especially in treating inflammatory diseases and cancers. In this study, we performed a cell-based high-throughput screening to discover novel agents capable of inhibiting NF-κB signaling. On the basis of two hit scaffolds from the screening, we synthesized 69 derivatives to optimize the potency for inhibition of NF-κB activation, leading to successful discovery of the most potent compound Z9j with over 170-fold enhancement of inhibitory activity. Preliminary mechanistic studies revealed that Z9j inhibited NF-κB signaling via suppression of Src/Syk, PI3K/Akt, and IKK/IκB pathways. This novel compound also demonstrated antiinflammatory and anticancer activities, warranting its further development as a potential multifunctional agent to treat inflammatory diseases and cancers.
    MeSH term(s) Anti-Inflammatory Agents/chemical synthesis ; Anti-Inflammatory Agents/chemistry ; Anti-Inflammatory Agents/pharmacology ; Antineoplastic Agents/chemical synthesis ; Antineoplastic Agents/chemistry ; Antineoplastic Agents/pharmacology ; Drug Discovery ; Drug Evaluation, Preclinical ; HeLa Cells ; High-Throughput Screening Assays ; Humans ; NF-kappa B/metabolism ; Signal Transduction/drug effects ; Small Molecule Libraries/chemical synthesis ; Small Molecule Libraries/chemistry ; Small Molecule Libraries/pharmacology ; Structure-Activity Relationship
    Chemical Substances Anti-Inflammatory Agents ; Antineoplastic Agents ; NF-kappa B ; Small Molecule Libraries
    Language English
    Publishing date 2018-07-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 218133-2
    ISSN 1520-4804 ; 0022-2623
    ISSN (online) 1520-4804
    ISSN 0022-2623
    DOI 10.1021/acs.jmedchem.7b01557
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.B 151: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 2021: Bestellungen von Artikeln über das Online-Bestellformular
    ab Jg. 2022: Lesesaal (EG)
    Zs.MB 1: Show issues

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

To top