Browsing by Author "Bharatam, Prasad V."

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    Synthesis of 1,4-dihydropyrazolo[4,3-b]indoles via intramolecular C(sp2)-N bond formation involving nitrene insertion, DFT study and their anticancer assessment
    (Academic Press Inc., 2021-06-29T00:00:00) Kaur, Manpreet; Mehta, Vikrant; Abdullah Wani, Aabid; Arora, Sahil; Bharatam, Prasad V.; Sharon, Ashoke; Singh, Sandeep; Kumar, Raj
    We herein report a new synthetic route for a series of unreported 1,4-dihydropyrazolo[4,3-b]indoles (6�8) via deoxygenation of o-nitrophenyl-substituted N-aryl pyrazoles and subsequent intramolecular (sp2)-N bond formation under microwave irradiation expedite modified Cadogan condition. This method allows access to NH-free as well as N-substituted fused indoles. DFT study and controlled experiments highlighted the role of nitrene insertion as one of the plausible reaction mechanisms. Furthermore, the target compounds exhibited cytotoxicity at low micromolar concentration against lung (A549), colon (HCT-116), and breast (MDA-MB-231, and MCF-7) cancer cell lines, induced the ROS generation and altered the mitochondrial membrane potential of highly aggressive MDA-MB-231 cells. Further investigations revealed that these compounds were selective Topo I (6h) or Topo II (7a, 7b) inhibitors. � 2021 Elsevier Inc.
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    Unanticipated Cleavage of 2-Nitrophenyl-Substituted N-Formyl Pyrazolines under Bechamp Conditions: Unveiling the Synthesis of 2-Aryl Quinolines and Their Mechanistic Exploration via DFT Studies
    (American Chemical Society, 2018) Joshi, Gaurav; Wani, Aabid Abdullah; Sharma, Sahil; Bhutani, Priyadeep; Bharatam, Prasad V.; Paul, Atish T.; Kumar, Raj
    We herein report for the first time an unusual decomposition of 2-nitrophenyl-substituted N-formyl pyrazolines under Bechamp reduction condition employed to yield 2-aryl quinolines exclusively instead of pyrazolo[1,5-c]quinazolines. The reaction investigation suggests acid-mediated cleavage of 1 followed by a retro-Michael addition, and a subsequent in situ intramolecular reductive cyclization through a modified Friedlander mechanism afforded 2-aryl quinolines (2) in good yields. The proposed mechanistic pathways were supported via experimental evidence and density functional theory studies. B3LYP/6-31+G(d) analysis indicated the involvement of trans-2-hydroxyaminochalcone as a key intermediate and its isomerization and cyclization, leading to unusual product formation.