Browsing by Author "Ashvani Yadav"

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Hypervalent Iodine Mediated Synthesis of Thiosulfonates from Sulfonyl Hydrazides and Their Transformation into Symmetrical Disulfides
(Georg Thieme Verlag, 2024) Ashvani Yadav; Rohit Kumar; Virendra Prasad
A transition-metal-free synthesis of thiosulfonates has been accomplished by the disproportionate coupling of readily available and inexpensive sulfonyl hydrazides embracing hypervalent iodine(III) [phenyliodine(III) diacetate (PIDA)] as an oxidant. This synthesis involves cleavage of the S-N bond and is endowed with creation of a new S-S bond. The thiosulfonates were further reduced with CS2/KOH to obtain symmetrical disulfides. This protocol features mild reaction conditions in open air, an inexpensive oxidant, and high functional group tolerance with good to excellent product yields. © 2024. Thieme. All rights reserved.
Metal-Free Desulfonylative and C-H Halogenation of Arenes: A Novel Approach for Haloarene Synthesis
(John Wiley and Sons Inc, 2025) Vikas G. Yadav; Rohit Kumar; Mitushree Ghosh; Ashvani Yadav; Virendra Prasad
We report a novel metal-free approach for the desulfonylative halogenation of aryl sulfonyl chlorides and the C-H halogenation of arenes. This strategy employs hypervalent iodine(III) as both an oxidant and a group transfer agent with tetrabutylammonium halides (TBAX) as a halide source. The method offers several key benefits, including the use of inexpensive and readily available reagents, simple reaction conditions, compatibility with air, and the absence of transition metals. © 2025 Wiley-VCH GmbH.
New trends in asymmetric catalysis: Chiral hypervalent iodine compounds as green and sustainable catalysts
(wiley, 2024) Vikas Yadav; Rohit Kumar; Amrit Gond; Ashvani Yadav; Mitushree Ghosh; Ram Singh Kuri; Virendra Prasad
Catalysis is widely recognized as a fundamental aspect of synthesis owing to the significant advancements made in the development of numerous catalysts, catalytic protocols, and methodologies over the past few decades. Among the diverse forms of catalysis, asymmetric catalysis has experienced significant growth in contemporary times. In the literature, many significant catalysts have been established for asymmetric synthesis. Organocatalysis is being employed as a preferred alternative to asymmetric enzymatic and metallic catalytic processes. Significantly, with regard to asymmetric redox reactions, organocatalysis has yielded remarkably exceptional outcomes. However, it is regrettable that asymmetric organocatalytic oxidations have proven to be exceedingly arduous. In order to address the challenges associated with asymmetric oxidations, chiral hypervalent iodine compounds have emerged as superior alternatives. Currently, numerous chiral hypervalent iodine compounds have been established and widely recognized for asymmetric synthesis. Chiral hypervalent iodine (III/V)-catalyzed asymmetric oxidations represent an efficient approach for enantioenriched compounds and intermediates of significant importance. Such reactions hold great promise for the development of novel therapeutic agents. The construction of chiral hypervalent iodines (III/V) through asymmetric organocatalytic oxidations has established a promising area in asymmetric chemistry. Several noteworthy asymmetric reactions include the oxidative dearomatization of phenols, ketone oxygenation, and alkene dioxygenation. This chapter presents a concise overview of several catalytic properties exhibited by hypervalent iodines (III/V) and their use for stereoselective oxidative rearrangement of disubstituted unactivated olefins. A catalytic method for the multi-O-C coupling of alkyne in a simple one-step process has been developed. This method is utilized for the synthesis of valuable a-ketoesters and their chiral analogs. Furthermore, an expanding yet insufficiently researched group of stereogenic substances known as axially chiral C-N compounds possesses the capacity to serve as chiral ligands and biologically active frameworks that can be developed. Moreover, a noteworthy progression in enantioselective catalysis pertains to the asymmetric oxidative dearomatization of naphthol carboxylic acids, which leads to the formation of spirolactones. This process is facilitated by a recently developed conformationally rigid oxo-bridged hypervalent iodine (III) species. Hypervalent iodine (III/V) reagents, characterized by their ease of handling, lack of toxicity, mildness, environmental friendliness (as green oxidants), and high stability, have been employed in numerous reactions and have facilitated the exploration of previously unexplored enantioselective transformations. This chapter aims to collate the reactions documented in the field of asymmetric hypervalent iodine chemistry, with a particular emphasis on the synthesis of chiral iodine (III and V) reagents or chiral iodoarenes. © 2024 Scrivener Publishing LLC. All rights reserved.
Regioselective sulfenylation of indoles using sulfonyl hydrazides: In silico design, DFT calculation, hirshfeld surface analysis, ADMET study, molecular docking and anticancer activity
(Elsevier B.V., 2025) Ashvani Yadav; Vishal K. Singh; Rohit Kumar; Vikas G. Yadav; Ashish Kumar Kushwaha; Vikas Kumar Rana; Ajay Kumar; Virendra Prasad
We report the design, synthesis, and anticancer evaluation of some novel indole thioethers, constructed via an efficient and regioselective sulfenylation of indoles with sulfonyl hydrazides, facilitated by KSCN. This method offers a valuable tool for the synthesis of a variety of indole thioethers under mild reaction conditions with good to excellent yields. Initially, the drug like properties of all compounds were evaluated. Subsequently, six lead compounds were subjected to molecular docking studies targeting the active site of the B-RAF protein (PDB ID: 1UWH). These compounds demonstrated strong interactions with key amino acid residues, including Lys482 (3.47 Å), Gln529 (3.28 Å), Thr528 (2.85 Å), Phe467 (2.85 Å), Gly95 (2.86 Å), Thr598 (3.30 Å), His538 (3.37 Å), Ser535 (3.22 Å), and Asn579 (3.43 Å), suggesting their potential as anticancer agents. DFT calculations of the novel thioethers revealed their energy gaps and binding affinities, while Hirshfeld surface analysis highlighted significant intermolecular interactions within their crystal structures. In vitro cell-based assays were conducted on selected compounds to assess their cytotoxicity against human cancer cell lines. The results suggest that extending the exposure duration beyond 24 h may uncover significant cytotoxic effects. In conclusion, these compounds exhibit promising potential as anticancer agents against the tested human cancer cell lines. © 2025 Elsevier B.V.
Regioselective Thiolation of Indole to Construct 3-Arylthioindoles
(Bentham Science Publishers, 2025) Ashvani Yadav; Rohit Kumar; Vikas G. Yadav; Mitushree Ghosh; Virendra Prasad
A practical and novel approach for the regioselective synthesis of 3-arylthioindole derivatives has been accomplished using a combination of indole substrates with p-toluene sulfonyl hydrazide. This methodology employs NIS as the oxidant and PPh3 as the reductant to give the desired 3-arylthioindoles in good to excellent yields. This method offers several advantages, including simplicity, operational ease, and broad substrate scope. © 2025 Bentham Science Publishers.
Synthesis of novel NHC-based transition metal complexes of Pd(II), Au(I), Cu(I) and Ir(III) with pendant 1,2,3-triazole group for remediation of rhodamine B
(Elsevier B.V., 2023) Amrit Gond; Subhash Chandra; Ashvani Yadav; Virendra Prasad; Vijay Shankar; Lallan Prasad; Rajesh Ram
The transition metal-NHC complexes presented here were all created by us. For instance, A bidentate ligand, [L1-H(Br)] having 1-methyl imidazolium salt, using for N-heterocyclic carbene as precursor, connected to a pendant triazole moiety via methylene bridge has been synthesized via ‘CuAAC’ or ‘Click’ reaction. Imidazolium salt, [L1-H(PF6)] with a non-coordinating anion PF6 has been prepared via anion exchange of [L1-H(Br)] with NH4PF6. Reaction of [L1-H(PF6)] with half an equivalent of Ag2O yielded the Ag(I)–NHC complex [(L1)2Ag](PF6). This Ag(I)–NHC complex is shown to be an excellent carbene transfer agent to other transition metals, both linear and non-linear, when reacted with appropriate equivalents of metal precursors to give variety of organometallic metal-NHC complexes via transmetallation. The compound [(L1)IrCl(Cp*)](PF6) has been applied for the remediation of a water pollutant rhodamine B dye from wastewater. The results of this study also provide good opportunities for organic synthesis in future research. © 2023 Elsevier B.V.
Synthesis of Symmetrical Disulfides by an NIS/PPh 3-Mediated Reductive Self-Coupling of Sulfonyl Hydrazides
(Georg Thieme Verlag, 2023) Ashvani Yadav; Amrit Gond; Virendra Prasad
The present study discloses an NIS/PPh3-mediated reductive self-coupling of arylsulfonyl hydrazides to prepare symmetric diaryl disulfides. This methodology has a broad functional-group tolerance and a high scalability. This strategy permits the introduction of sulfonyl hydrazides into the synthesis of symmetrical organic disulfides without the use of a catalyst or base, and symmetrical aromatic disulfides can be prepared in moderate to excellent isolated yields from inexpensive and readily available starting materials. © 2023. Thieme. All rights reserved.