Browsing by Author "Kumar, Sunit"

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    Copper catalysed regioselective synthesis of pyrimidine substituted Indolizino[8,7-b]indole derivatives via cascade A3 annulation
    (Elsevier Ltd, 2023-07-08T00:00:00) Kumar, Sunit; Kumar, Rakesh; Malakar, Chandi C.; Singh, Virender
    Cu(II) salt has been found to be an efficient catalyst for the regioselective synthesis of a series of novel indolizino [8,7-b]indole derivatives with pyrimidine tethers via three-component annulation of 1-formyl-9H-?-carbolines (Kumujian C), 2-amino-pyrimidines and terminal alkynes. The reactions proceeds through Cu-catalysed A3-coupling followed by intramolecular cyclisation in a cascade manner. The scope of strategy has been exemplified with a library of biologically interesting 25 indolizino [8,7-b]indoles with pyrimidine tethers which mimics several natural products. � 2023 Elsevier Ltd
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    Cu(II)-Catalysed Azide-Alkyne Cycloaddition Reaction towards Synthesis of ?-Carboline C1-Tethered 1,2,3-Triazole Derivatives
    (John Wiley and Sons Inc, 2021-04-27T00:00:00) Kumar, Sunit; Malakar, Chandi C.; Singh, Virender
    Indole and ?-carboline alkaloids exhibit diverse range of significant pharmacological properties as reflected by their contribution in drug-discovery. We have described the synthesis of hybrid molecules containing ?-carboline C1-linked 1,2,3-triazoles in moderate to good yields. The developed transformation was realized by using Cu(II)-catalysed click-reaction of diverse alkynes with in-situ derived rarely explored ?-carboline tethered aliphatic azides. These molecular hybrids also exhibited excellent fluorescence properties. � 2021 Wiley-VCH GmbH
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    An efficient metal-free and catalyst-free C�S/C�O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides
    (Beilstein-Institut Zur Forderung der Chemischen Wissenschaften, 2023-03-02T00:00:00) Sharma, Shubham; Singh, Dharmender; Kumar, Sunit; Vaishali; Jamra, Rahul; Banyal, Naveen; Deepika; Malakar, Chandi C.; Singh, Virender
    An operationally simple and metal-free approach is described for the synthesis of pyrazole-tethered thioamide and amide conjugates. The thioamides were generated by employing a three-component reaction of diverse pyrazole C-3/4/5 carbaldehydes, secondary amines, and elemental sulfur in a single synthetic operation. The advantages of this developed protocol refer to the broad substrate scope, metal-free and easy to perform reaction conditions. Moreover, the pyrazole C-3/5-linked amide conjugates were also synthesized via an oxidative amination of pyrazole carbaldehydes and 2-aminopyridines using hydrogen peroxide as an oxidant. � 2023 Sharma et al.
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    Iodine-Catalysed Synthesis of ?-Carboline Tethered ?-Amino Amidines Through Ugi-Type Multicomponent Reaction
    (John Wiley and Sons Inc, 2022-09-15T00:00:00) Singh, Manpreet; Vaishali; Jamra, Rahul; Deepika; Kumar, Sunit; Singh, Virender
    A simple and efficient iodine catalysed protocol has been unfolded for the synthesis of novel ?-carboline C1-linked ?-amino amidines via one-pot assembly of 1-formyl ?-carbolines (Kumujian C analogues), anilines and isocyanides. This domino strategy proceeds through the formation of three C?N bonds in a single operation. The advantageous features of the developed methodology include one-pot synthesis, operational simplicity, high atom economy, broad substrate scope, multicomponent character, easy purification procedure (no column chromatography) and applicability towards gram scale synthesis. The scope of strategy has been demonstrated with the construction of a library of 32 novel ?-carboline tethered ?-amino amidines having three points of diversity. � 2022 Wiley-VCH GmbH.