Browsing by Author "Singh, Dharmender"

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    Efficient approach towards the polysubstituted 4h-pyran hybrid quinolone derivatives and subsequent copper-catalyzed hydroxylation of haloarenes
    (Japan Institute of Heterocyclic Chemistry, 2021-03-16T00:00:00) Kumar, Vipin; Singh, Dharmender; Gujjarappa, Raghuram; Malakar, Chandi C.; Singh, Virender
    A proficient and feasible approach towards polysubstituted quinolone conjugated 4H-pyrans has been elucidated. The illustrated phenomenon concern with the base-mediated multicomponent reaction and subsequent copper-catalyzed hydroxylation of C-X bond emerging in an amide functionality. The developed reaction conditions showcased considerable substrate scope and functional group tolerance by giving the desired products in good yields. � 2021 Japan Institute of Heterocyclic Chemistry. All rights reserved.
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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.