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  1. Article ; Online: Relay Organophotoredox/

    Hussain, Yaseen / Sharma, Deepak / Tamanna / Chauhan, Pankaj

    Organic letters

    2023  Volume 25, Issue 14, Page(s) 2520–2524

    Abstract: An unprecedented highly stereoselective synthesis of pyrrolo[1,2- ...

    Abstract An unprecedented highly stereoselective synthesis of pyrrolo[1,2-
    Language English
    Publishing date 2023-04-04
    Publishing country United States
    Document type Journal Article
    ISSN 1523-7052
    ISSN (online) 1523-7052
    DOI 10.1021/acs.orglett.3c00685
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  2. Article ; Online: Catalytic asymmetric umpolung reactions of imines

    Hussain, Yaseen / Chauhan, Pankaj

    Organic & biomolecular chemistry

    2021  Volume 19, Issue 19, Page(s) 4193–4212

    Abstract: The imine umpolung is a relatively new and interesting strategy, especially in catalytic asymmetric synthesis. A significant development in organo- and transition metal-catalyzed umpolung of imines took place only in the recently concluded decade. A ... ...

    Abstract The imine umpolung is a relatively new and interesting strategy, especially in catalytic asymmetric synthesis. A significant development in organo- and transition metal-catalyzed umpolung of imines took place only in the recently concluded decade. A majority of the reports on the asymmetric umpolung of imines involve the initial generation of 2-azaallyl anion intermediates with the chiral catalysts, which serve as a significant driving force for the umpolung addition/substitution reactions. A variety of organocatalysts such as bifunctional cinchona alkaloids including squaramides and thioureas, chiral BINOL derived phosphoric acids, phase transfer catalysts (PTCs), phosphines, and transition metal-complexes of iridium, copper and palladium have been employed to achieve the excellent level of asymmetric induction in such types of umpolung reactions. The asymmetric imine umpolung strategy has been applied successfully to synthesize synthetic amino-acid derivatives and other useful chiral amines, including drugs and potentially bioactive molecules. This review summarizes all the significant recent development in catalytic umpolung reactions of imines involving a 2-azaallyl anion intermediate.
    Language English
    Publishing date 2021-04-17
    Publishing country England
    Document type Journal Article ; Review ; Research Support, Non-U.S. Gov't
    ZDB-ID 2097583-1
    ISSN 1477-0539 ; 1477-0520
    ISSN (online) 1477-0539
    ISSN 1477-0520
    DOI 10.1039/d1ob00409c
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  3. Article ; Online: Carbene Formation or Reduction of the Diazo Functional Group? An Unexpected Solvent-Dependent Reactivity of Cyclic Diazo Imides.

    Hussain, Yaseen / Empel, Claire / Koenigs, Rene M / Chauhan, Pankaj

    Angewandte Chemie (International ed. in English)

    2023  Volume 62, Issue 40, Page(s) e202309184

    Abstract: The control of the reactivity of diazo compounds is commonly achieved by the choice of a suitable catalyst, e.g. via stabilization of singlet carbenes or radical intermediates. Herein, we report on the light-promoted reactivity of cyclic diazo imides ... ...

    Abstract The control of the reactivity of diazo compounds is commonly achieved by the choice of a suitable catalyst, e.g. via stabilization of singlet carbenes or radical intermediates. Herein, we report on the light-promoted reactivity of cyclic diazo imides with thiols, where the choice of solvent results in two fundamentally different reaction pathways. In dichloromethane (DCM), a carbene is formed initially and engages in a cascade C-H functionalization/thiolation reaction to deliver indane-fused pyrrolidines in good to excellent yields. When switching to acetonitrile solvent, the carbene pathway is shut down and an unusual reduction of the diazo compound occurs under otherwise identical reaction conditions, where the aryl thiol acts as reductant. A combined set of experimental and computational studies was carried out to obtain mechanistic understanding and to support that indane formation proceeds via the insertion of a triplet carbene, while the reduction of diazo imides proceeds via an electron transfer process.
    Language English
    Publishing date 2023-08-24
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2011836-3
    ISSN 1521-3773 ; 1433-7851
    ISSN (online) 1521-3773
    ISSN 1433-7851
    DOI 10.1002/anie.202309184
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  4. Article ; Online: Regulation of endoplasmic reticulum stress by hesperetin: Focus on antitumor and cytoprotective effects.

    Hussain, Yaseen / Khan, Haroon / Efferth, Thomas / Alam, Waqas

    Phytomedicine : international journal of phytotherapy and phytopharmacology

    2022  Volume 100, Page(s) 153985

    Abstract: Background: Cancer is still an all-times issue due to a large and even increasing number of deaths. Impaired genes regulating cell proliferation and apoptosis are targets for the development of novel cancer treatments.: Hypothesis: Increased ... ...

    Abstract Background: Cancer is still an all-times issue due to a large and even increasing number of deaths. Impaired genes regulating cell proliferation and apoptosis are targets for the development of novel cancer treatments.
    Hypothesis: Increased transcription of NADPH oxidase activator (NOXA), Bcl2-like11 (BIM), BH3-only proteins and p53 unregulated apoptosis modulator (PUMA) is caused by the imbalance between pro- and anti-apoptotic Bcl-2 proteins due to endoplasmic reticulum (ER) stress. The membranous network of ER is present in all eukaryotic cells. ER stress facilitates the interaction between Bax and PUMA, triggering the release of cytochrome C. As a main intracellular organelle, ER is responsible for translocation as well as post-translation modification and protein folding.
    Results: Hesperetin is a cytoprotective flavonone, which acts against ER stress and protects from cell damage induced by reactive oxygen species (ROS) and reactive nitrogen species (RNS). Hesperetin inhibits lipid peroxidation induced by Fe
    Conclusion: This review deals with the anticancer effects of hesperetin regarding the regulation of ER stress as a principal mechanism in the pathogenesis of tumors.
    MeSH term(s) Animals ; Antineoplastic Agents, Phytogenic/pharmacology ; Apoptosis ; Apoptosis Regulatory Proteins/metabolism ; Endoplasmic Reticulum Stress ; Hesperidin/pharmacology ; Rats
    Chemical Substances Antineoplastic Agents, Phytogenic ; Apoptosis Regulatory Proteins ; Hesperidin (E750O06Y6O) ; hesperetin (Q9Q3D557F1)
    Language English
    Publishing date 2022-02-12
    Publishing country Germany
    Document type Journal Article ; Review
    ZDB-ID 1205240-1
    ISSN 1618-095X ; 0944-7113
    ISSN (online) 1618-095X
    ISSN 0944-7113
    DOI 10.1016/j.phymed.2022.153985
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    Zs.A 4115: Show issues Location:
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  5. Article ; Online: Asymmetric Synthesis of Cyclohexenone-Fused Isochromans via Quinidine-Catalyzed Domino Peroxyhemiacetalization/Oxa-Michael Addition/Desymmetrization Sequence.

    Tamanna / Hussain, Yaseen / Sharma, Deepak / Chauhan, Pankaj

    The Journal of organic chemistry

    2022  Volume 87, Issue 9, Page(s) 6397–6402

    Abstract: A highly enantio- and diastereoselective synthesis of highly functionalized isochromans was achieved through an organocatalyzed domino reaction. Quinidine as the catalyst initiates a peroxyhemiacetalization/oxa-Michael/desymmetrization domino sequence ... ...

    Abstract A highly enantio- and diastereoselective synthesis of highly functionalized isochromans was achieved through an organocatalyzed domino reaction. Quinidine as the catalyst initiates a peroxyhemiacetalization/oxa-Michael/desymmetrization domino sequence between various 2,5-cyclohexadienone-tethered aryl aldehydes with hydroperoxides to generate the single diastereomers of isochromans appended with a cyclohexenone ring bearing three vicinal stereocenters in good yields and high enantioselectivities under ambient reaction conditions.
    MeSH term(s) Aldehydes ; Catalysis ; Quinidine ; Stereoisomerism
    Chemical Substances Aldehydes ; Quinidine (ITX08688JL)
    Language English
    Publishing date 2022-04-19
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.2c00215
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    Zs.A 4473: Show issues Location:
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  6. Article: Asymmetric Synthesis of Cyclohexenone-Fused Isochromans via Quinidine-Catalyzed Domino Peroxyhemiacetalization/Oxa-Michael Addition/Desymmetrization Sequence

    Tamanna / Hussain, Yaseen / Sharma, Deepak / Chauhan, Pankaj

    Journal of organic chemistry. 2022 Apr. 19, v. 87, no. 9

    2022  

    Abstract: A highly enantio- and diastereoselective synthesis of highly functionalized isochromans was achieved through an organocatalyzed domino reaction. Quinidine as the catalyst initiates a peroxyhemiacetalization/oxa-Michael/desymmetrization domino sequence ... ...

    Abstract A highly enantio- and diastereoselective synthesis of highly functionalized isochromans was achieved through an organocatalyzed domino reaction. Quinidine as the catalyst initiates a peroxyhemiacetalization/oxa-Michael/desymmetrization domino sequence between various 2,5-cyclohexadienone-tethered aryl aldehydes with hydroperoxides to generate the single diastereomers of isochromans appended with a cyclohexenone ring bearing three vicinal stereocenters in good yields and high enantioselectivities under ambient reaction conditions.
    Keywords catalysts ; diastereomers ; diastereoselective synthesis ; hydroperoxides ; organic chemistry ; quinidine
    Language English
    Dates of publication 2022-0419
    Size p. 6397-6402.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.2c00215
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    In stock of ZB MED Bonn / Germany

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  7. Article: Electrochemical cascade synthesis of α-thio-substituted masked aldehydes

    Sharma, Deepak / Hussain, Yaseen / Sharma, Manisha / Chauhan, Pankaj

    Green chemistry. 2022 June 20, v. 24, no. 12

    2022  

    Abstract: The recent upsurge in electrosynthesis has provided efficient and sustainable synthetic strategies for procuring valuable molecules and their precursors. In this context, we have achieved an efficient cascade synthesis of β,β-dialkoxy sulfides under ... ...

    Abstract The recent upsurge in electrosynthesis has provided efficient and sustainable synthetic strategies for procuring valuable molecules and their precursors. In this context, we have achieved an efficient cascade synthesis of β,β-dialkoxy sulfides under ambient electrochemical conditions. The electrolysis of terminal aryl alkynes, aromatic and aliphatic thiols, and alcohols initiates a cascade sequence involving the thiol–yne reaction/1,2-thio migration via nucleophilic attack of alkoxides to provide α-thio-substituted masked aldehydes in good yields for a diverse range of substrates. The cascade sequence also works well when using acetic acid and acetic anhydride instead of alcohols.
    Keywords Lewis bases ; acetic acid ; acetic anhydride ; alkynes ; electrochemistry ; electrolysis ; electrosynthesis ; green chemistry ; thiols
    Language English
    Dates of publication 2022-0620
    Size p. 4783-4788.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 2006274-6
    ISSN 1463-9270 ; 1463-9262
    ISSN (online) 1463-9270
    ISSN 1463-9262
    DOI 10.1039/d2gc00845a
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  8. Article: Regulation of endoplasmic reticulum stress by hesperetin: Focus on antitumor and cytoprotective effects

    Hussain, Yaseen / Khan, Haroon / Efferth, Thomas / Alam, Waqas

    Phytomedicine. 2022 Feb. 10,

    2022  

    Abstract: Cancer is still an all-times issue due to a large and even increasing number of deaths. Impaired genes regulating cell proliferation and apoptosis are targets for the development of novel cancer treatments. Increased transcription of NADPH oxidase ... ...

    Abstract Cancer is still an all-times issue due to a large and even increasing number of deaths. Impaired genes regulating cell proliferation and apoptosis are targets for the development of novel cancer treatments. Increased transcription of NADPH oxidase activator (NOXA), Bcl2-like11 (BIM), BH3-only proteins and p53 unregulated apoptosis modulator (PUMA) is caused by the imbalance between pro- and anti-apoptotic Bcl-2 proteins due to endoplasmic reticulum (ER) stress. The membranous network of ER is present in all eukaryotic cells. ER stress facilitates the interaction between Bax and PUMA, triggering the release of cytochrome C. As a main intracellular organelle, ER is responsible for translocation as well as post-translation modification and protein folding. Hesperetin is a cytoprotective flavonone, which acts against ER stress and protects from cell damage induced by reactive oxygen species (ROS) and reactive nitrogen species (RNS). Hesperetin inhibits lipid peroxidation induced by Fe²⁺ and L-ascorbic acid in rat brain homogenates. This review deals with the anticancer effects of hesperetin regarding the regulation of ER stress as a principal mechanism in the pathogenesis of tumors.
    Keywords NAD(P)H oxidase (H2O2-forming) ; apoptosis ; ascorbic acid ; brain ; cell proliferation ; endoplasmic reticulum ; endoplasmic reticulum stress ; hesperetin ; lipid peroxidation ; pathogenesis ; post-translational modification ; rats ; reactive nitrogen species ; reactive oxygen species
    Language English
    Dates of publication 2022-0210
    Publishing place Elsevier GmbH
    Document type Article
    Note Pre-press version
    ZDB-ID 1205240-1
    ISSN 1618-095X ; 0944-7113
    ISSN (online) 1618-095X
    ISSN 0944-7113
    DOI 10.1016/j.phymed.2022.153985
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    Zs.A 4115: Show issues Location:
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  9. Article ; Online: Stereoselective Oxidative Mannich Reaction of Ketones with Dihydrodibenzo-Oxazepines via a Merger of Photoredox-/Electro-Catalysis with Organocatalysis.

    Hussain, Yaseen / Sharma, Deepak / Kotwal, Namrata / Kumar, Indresh / Chauhan, Pankaj

    ChemSusChem

    2022  Volume 15, Issue 12, Page(s) e202200415

    Abstract: An enantio- and diastereoselective ... ...

    Abstract An enantio- and diastereoselective sp
    MeSH term(s) Catalysis ; Ketones ; Oxazepines ; Oxidation-Reduction ; Oxidative Stress ; Stereoisomerism
    Chemical Substances Ketones ; Oxazepines
    Language English
    Publishing date 2022-04-29
    Publishing country Germany
    Document type Journal Article
    ISSN 1864-564X
    ISSN (online) 1864-564X
    DOI 10.1002/cssc.202200415
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  10. Article: Nanoscale delivery of phytochemicals targeting CRISPR/Cas9 for cancer therapy

    Hussain, Yaseen / Khan, Haroon / Ahmad, Imad / Efferth, Thomas / Alam, Waqas

    Phytomedicine. 2022 Jan., v. 94

    2022  

    Abstract: With growing global prevalence, cancer is a major cause of disease-related deaths. The understanding of the fundamental tumor pathology has contributed to the development of agents targeting oncogenic signaling pathways. Although these agents have ... ...

    Abstract With growing global prevalence, cancer is a major cause of disease-related deaths. The understanding of the fundamental tumor pathology has contributed to the development of agents targeting oncogenic signaling pathways. Although these agents have increased survival for defined cancers, the therapeutic choices are still limited due to the development of drug resistance. CRISPR/Cas9 is a powerful new technology in cancer therapy by facilitating the identification of novel treatment targets and development of cell-based treatment strategies. We focused on applications of the CRISPR/Cas9 system in cancer therapy and discuss nanoscale delivery of cytotoxic phytochemical targeting the CRISPR/Cas9 system. Genome engineering has been significantly accelerated by the advancement of the CRISPR/Cas9 technique. Phytochemicals play a key role in treating cancer by targeting various mechanisms and pathways. The use of CRISPR/Cas9 for nanoscale delivery of phytochemicals opens new avenues in cancer therapy. One of the main obstacles in the clinical application of CRISPR/Cas9 is safe and efficient delivery. As viral delivery methods have certain drawbacks, there is an urgent need to develop non-viral delivery systems for therapeutic applications.
    Keywords CRISPR-Cas systems ; cancer therapy ; cytotoxicity ; drug development ; drug resistance ; neoplasms ; phytochemicals
    Language English
    Dates of publication 2022-01
    Publishing place Elsevier GmbH
    Document type Article
    ZDB-ID 1205240-1
    ISSN 1618-095X ; 0944-7113
    ISSN (online) 1618-095X
    ISSN 0944-7113
    DOI 10.1016/j.phymed.2021.153830
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