Chemistry - Research Publications

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Author: search.filters.author.Banerjee, BiplabSubject: search.filters.subject.Article

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    Visible-Light-Induced Metal- and Photocatalyst-Free Radical Cascade Cyclization of Cinnamamides for Synthesis of Functionalized Dihydroquinolinones
    (American Chemical Society, 2023-07-18T00:00:00) Nishad, Chandra Shekhar; Suman, Pallav; Saha, Himadri; Banerjee, Biplab
    Visible-light-promoted metal- and photocatalyst-free radical cascade cyclization of cinnamamides with ?-oxocarboxylic acids is described for sustainable synthesis of diverse pharmaceutically important dihydroquinolinone scaffolds in one pot under mild conditions. The decarboxylative cascade cyclization proceeded efficiently at room temperature without the need for expensive photocatalysts such as Ir or Ru complexes, which indicates the practicability and environmentally benign nature of this protocol. Preliminary mechanistic studies reveal that the blue LED irradiation efficiently cleaves the I-O bond of the hypervalent iodine reagent PhI(O2CCOAr)2 formed through ligand exchange between iodobenzene diacetate and arylglyoxylic acid to initiate the cascade reaction. The synthetic value of this operationally simple and energy-efficient method is further demonstrated by late-stage functionalization of drug molecules in excellent yields. � 2023 American Chemical Society.
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    Metal-Free Direct Access to N-Sulfonyl Amidines from Sulfonamides and Secondary Amines Involving Tandem C-N Bond Formations
    (American Chemical Society, 2022-08-17T00:00:00) Nishad, Chandra Shekhar; Haldar, Krishna Kanta; Banerjee, Biplab
    We report a mild and efficient metal-free one-pot procedure for the synthesis of N-sulfonyl amidines via the direct reaction of sulfonamides with secondary amines without using any additives. A wide range of substrates with variety of functional groups is well tolerated under the reaction conditions. Preliminary mechanistic studies indicate that the secondary amine plays a dual role as a C1 source of the amidine group and an aminating agent. Synthetic utility of this method is shown in the late-stage functionalization of drug molecules on the gram scale. � 2022 American Chemical Society.