Browsing by Author "Anup Kumar Sharma"
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PublicationArticle A Copper-Catalyzed Synthesis of Pyridoquinazolinones via C(sp2)-H Functionalization and Annulation of Benzoic Acids with 2-Aminopyridines(American Chemical Society, 2024) Mahesh Kumar; Anup Kumar Sharma; Km Ishu; Krishna Nand SinghA facile synthesis of pyridoquinazolinones has been accomplished via C(sp2)-H functionalization and annulation of benzoic acids with 2-aminopyridines using Cu(OAc)2 as catalyst in DMSO. The reaction involves the formation of amides which on ortho amination followed by trans-amidation afford a wide array of products under ligand/base-free conditions. © 2024 American Chemical Society.PublicationArticle An Efficient Synthesis of 1,2-Diketones by Oxidative Cross-coupling of Alkynes and Aryl Triazenes using Copper Catalysis(Wiley-Blackwell, 2019) Ramesh Kumar Vishwakarma; Saurabh Kumar; Anup Kumar Sharma; Rahul Singh; Krishna Nand SinghAn efficient and mild approach to 1,2-diketones has been developed via oxidative cross-coupling of alkynes and aryl triazenes using copper catalysis under open atmosphere. The approach is convenient, clean, and offers a wide range of substrate scope and functional group tolerance. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimPublicationArticle Copper-Catalyzed Decarboxylative Synthesis of α-Ketothioamides Using α,β-Unsaturated Arylcarboxylic Acids, Alicyclic Secondary Amines and Elemental Sulfur(John Wiley and Sons Inc, 2021) Anjali Jaiswal; Anup Kumar Sharma; Preeti; Krishna Nand SinghAn efficient and straightforward synthesis of α-ketothioamides has been accomplished via in situ decarboxylative oxidative thioamidation using α,β-unsaturated arylcarboxylic acids, alicyclic secondary amines and elemental sulfur under solvent-free aerobic conditions. © 2021 Wiley-VCH GmbH.PublicationArticle Copper-Catalyzed Thiolation of Hydrazones with Sodium Sulfinates: A Straightforward Synthesis of Benzylic Thioethers(American Chemical Society, 2023) Anand Kumar Pandey; Shiv Chand; Anup Kumar Sharma; Krishna Nand SinghA facile and sustainable protocol for the thiolation of hydrazones with sodium sulfinates has been developed in the presence of CuBr2 and DBU in DMF to afford diverse benzylic thioethers. Control experiments reveal a radical pathway involving a thiyl radical as a key intermediate. © 2022 American Chemical Society.PublicationArticle Cu-Catalysed oxidative amidation of cinnamic acids/arylacetic acids with 2° amines: An efficient synthesis of α-ketoamides(Royal Society of Chemistry, 2019) Anup Kumar Sharma; Anjali Jaiswal; Krishna Nand SinghA new and convenient copper-catalysed synthesis of α-ketoamides has been accomplished using readily available cinnamic acids/arylacetic acids and 2° amines in an open atmosphere. The reaction between cinnamic acid and amine involves the formation of enamine followed by its aerobic oxidation, whereas the reaction of arylacetic acid with amine involves amide formation followed by benzylic methylene oxidation. © 2019 The Royal Society of Chemistry.PublicationArticle Domino Reaction of Isatins with α-Oxoketene-N,S-acetals: An Efficient Synthesis of Pyrrolo[3,4-c]quinoline-1,3-diones and 2,3-Dihydro-1H-pyrrolo[3,4-c]quinolin-1-ones(John Wiley and Sons Inc, 2021) Anup Kumar Sharma; Anjali Jaiswal; Shiv Chand; Krishna Nand SinghA straightforward synthesis of pyrrolo[3,4-c]quinoline-1,3-diones and 2,3-dihydro-1H-pyrrolo[3,4-c]quinolin-1-ones has been accomplished by the cascade reaction of isatins with α-oxoketene-N,S-acetals using BF3 ⋅ Et2O in DMSO/toluene at 110 °C. The reaction offers an easy access to biologically important tricyclic N-heterocycles via C−C/C−X bond formation. © 2021 Wiley-VCH GmbHPublicationArticle Easy access to α-carbonyl sulfones using cross-coupling of α-aryl-α-diazoesters with sulfonyl hydrazides(Royal Society of Chemistry, 2022) Anup Kumar Sharma; Shiv Chand; Anand Kumar Pandey; Krishna Nand SinghA facile synthesis of α-carbonyl sulfones has been accomplished by the cross-coupling of α-aryl-α-diazoesters with sulfonyl hydrazides in the presence of CuI and DBU. The reaction employs inexpensive and bench stable sulfonyl hydrazides as a sulfonyl source, and facilitates the migratory insertion with α-aryl-α-diazoesters under mild reaction conditions. © 2023 The Royal Society of Chemistry.PublicationArticle Iodine Catalyzed Sulfenylation of Sodium Sulfinates Using Arenediazonium Tetrafluoroborate/CS2 Combination(John Wiley and Sons Inc, 2022) Anand Kumar Pandey; Shiv Chand; Anup Kumar Sharma; Krishna Nand SinghAn approach to unsymmetrical thiosulfonates has been developed using sulfenylation of sodium sulfinates by arenediazonium tetrafluoroborate/CS2 combination with iodine as catalyst. The reaction is simple, high yielding, scalable, and proceeds smoothly with good substrate scope and functional group tolerance. © 2022 Wiley-VCH GmbH.PublicationArticle Iodine-catalyzed thioallylation of indoles using Bunte salts prepared from Baylis-Hillman bromides(Royal Society of Chemistry, 2021) Prince Kumar Gupta; Arvind Kumar Yadav; Anup Kumar Sharma; Krishna Nand SinghMetal-free iodine-catalyzed regioselective thioallylation of indoles has been accomplished at room temperature using Bunte salts prepared from Baylis-Hillman bromides. The resulting multi-functional C3 thioallylated indoles exhibit ample structural diversity and good functional group tolerance. © The Royal Society of Chemistry 2021.PublicationArticle Metal-Free Decarboxylative Cyanomethylation of β-Aryl/Heteroaryl Substituted α,β-Unsaturated Carboxylic Acids to γ-Ketonitriles(American Chemical Society, 2024) Shiv Chand; Saurabh Kumar; Anup Kumar Sharma; Krishna Nand SinghA decarboxylative cyanomethylation of β-aryl/heteroaryl substituted α,β-unsaturated carboxylic acids has been accomplished via C(sp3)-H activation of alkyl nitriles to afford diverse γ-ketonitriles by making use of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and tert-butyl hydroperoxide (TBHP). The present report offers a metal-free approach and is featured with a broad substitution pattern and functional group compatibility. © 2024 American Chemical Society.PublicationArticle Nickel Catalyzed Ipso-hydroxylation and Subsequent Cross Dehydrogenative Coupling of Arylboronic Acids with Tertiary Amines: A Facile Access to α-phenolated Tertiary Amines(Wiley-VCH Verlag, 2018) Promod Kumar; Anup Kumar Sharma; Rahul Singh; Tirumaleswararao Guntreddi; Krishna Nand SinghA straightforward and new approach has been developed for the α-functionalization of tertiary amines via sequential oxidative hydoxylation and cross-dehydrogenative coupling (CDC) of arylboronic acids with tertiary amines to afford α-phenolated tertiary amines. The results demonstrate an easy arylation of C(sp3)−H bond in the presence of an inexpensive and readily available nickel metal salt. (Figure presented.). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimPublicationArticle Photoredox Catalyzed Cyclization of Enaminones/Ketene N,S-Acetals with β-Ketodinitriles to Access Polysubstituted Pyrroles(American Chemical Society, 2025) Anup Kumar Sharma; Pratima Singh; Krishna Nand SinghA facile synthesis of polyfunctionalized pyrroles has been explored via photoredox cascade cyclization of enaminones/ketene N,S-acetals with β-ketodinitriles using eosin Y, CuI, and Ag2CO3in acetonitrile under blue LED irradiation at room temperature. The present report offers an efficient and straightforward approach to pyrrole-3-carboxylic acids and pyrrole-3-carboxamides with wide substrate scope and functional group tolerance. © 2025 American Chemical SocietyPublicationArticle Silver-Catalyzed Decarboxylative Trifluoromethylthiolation of Cinnamic Acids: An Easy Access to α-Trifluoromethylthiolated Ketones(Wiley-VCH Verlag, 2018) Anup Kumar Sharma; Arvind Kumar Yadav; Krishna Nand SinghA silver-catalyzed decarboxylative difunctionalization of cinnamic acids has been developed to afford a variety of α-trifluoromethylthiolated ketones under mild reaction conditions using in situ generated SCF3 source by the combination of Langlois’ reagent and CS2. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimPublicationArticle Sulfur-Mediated Decarboxylative Amidation of Cinnamic Acids via C═C Bond Cleavage(American Chemical Society, 2024) Mahesh Kumar; Anup Kumar Sharma; Km Ishu; Krishna Nand SinghA new strategy for the synthesis of amides has been developed using sulfur-mediated decarboxylative coupling of cinnamic acids with amines via oxidative cleavage of the C═C bond. © 2024 American Chemical SocietyPublicationArticle Synthesis of 3-acylindoles: via copper-mediated oxidative decarbethoxylation of ethyl arylacetates(Royal Society of Chemistry, 2020) Anjali Jaiswal; Anup Kumar Sharma; Krishna Nand SinghAn efficient regioselective C-3 acylation of free indoles (N-H) has been accomplished via oxidative decarbethoxylation of easily available ethyl arylacetates using Cu(OAc)2 and KOtBu in DMSO. This journal is © 2020 The Royal Society of Chemistry.PublicationArticle Synthesis of unsymmetrical ketones via dual catalysed cross-coupling of α,β-unsaturated carboxylic acids with aryldiazonium salts(Royal Society of Chemistry, 2023) Shiv Chand; Anup Kumar Sharma; Anand Kumar Pandey; Krishna Nand SinghA visible light-enabled synthesis of unsymmetrical ketones has been accomplished by the cross-coupling of α,β-unsaturated carboxylic acids and aryldiazonium salts embracing a synergistic eosin Y and Co(OAc)2·4H2O catalysis. The reaction involves decarboxylative aerobic C C bond cleavage, and is endowed with the creation of new C-C and C-O bonds with good substrate scope. © 2023 The Royal Society of Chemistry.PublicationArticle Tandem Synthesis of Polysubstituted Pyrroles via Cu(I)-Catalyzed Cyclization of Ketene N,S-Acetals with β-Ketodinitriles(American Chemical Society, 2025) Anup Kumar Sharma; Mahesh Kumar; Shiv Chand; Krishna Nand SinghA new approach to multifunctionalized pyrroles has been explored by the tandem cyclization of α-oxoketene-N,S-acetals with β-ketodinitriles using Cu(MeCN)4BF4 and Ag2CO3 in toluene under reflux conditions. The reaction involves C-C/C-N bond creation, and is assumed to proceed via enamine formation, intramolecular cyclization, and rearrangement. The potential of the methodology has also been demonstrated for a gram-scale reaction as well as for some useful organic transformations. The reaction offers a practical pathway to achieve polysubstituted pyrroles with broad substrate scope and good functional group tolerance. © 2025 American Chemical Society.PublicationArticle Transition-Metal-Free Cross-Dehydrogenative Coupling of Ethyl Arylacetates with Benzoic/Cinnamic Acids: A Practical Synthesis of α-Acyloxy Esters(Wiley-VCH Verlag, 2018) Anup Kumar Sharma; Promod Kumar; Ramesh Kumar Vishwakarma; Krishna Nand SinghAn efficient cross-dehydrogenative coupling of benzylic C(sp3)−H of ethyl arylacetates with benzoic/cinnamic acids has been developed to afford α-acyloxy esters in reasonably high yields under environmentally benign conditions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimPublicationArticle Transition-Metal-Free Regiospecific Aroylation of Nitroarenes Using Ethyl Arylacetates at Room Temperature(American Chemical Society, 2018) Promod Kumar; Anup Kumar Sharma; Tirumaleswararao Guntreddi; Rahul Singh; Krishna Nand SinghA novel regiospecific C(sp3)-C(sp2) coupling between ethyl arylacetates and nitroarenes has been developed to deliver biaryl ketones in excellent yields. The protocol is metal-free, mild, and compatible with a number of functional groups on both of the reacting partners. © 2018 American Chemical Society.PublicationArticle Visible light enabled γ-trifluoromethylation of Baylis-Hillman acetates: Stereoselective synthesis of trisubstituted alkenes(Royal Society of Chemistry, 2019) Arvind Kumar Yadav; Anup Kumar Sharma; Krishna Nand SinghA distinct visible light induced γ-trifluoromethylation of Baylis-Hillman acetates has been accomplished using eosin Y as a photoredox catalyst and bench stable Langlois' reagent (CF3SO2Na) as a CF3 source under metal-free conditions at room temperature to afford various trisubstituted alkenes. The product stereochemistry is predominantly trans (E), and involves trifluoromethylation followed by de-acetoxylation. © 2019 the Partner Organisations.