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Viktor V. Zhdankin - One of the best experts on this subject based on the ideXlab platform.
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Benziodoxole-Derived Organosulfonates: The Strongest Hypervalent Iodine Electrophiles and Oxidants
Synlett, 2019Co-Authors: Mekhman S. Yusubov, Akira Yoshimura, Pavel Postnikov, Viktor V. ZhdankinAbstract:This account describes the development of organosulfonyloxy-substituted iodine(III) and iodine(V) benziodoxole derived reagents, which are thermally stable compounds with useful reactivity patterns. Iodine(III) benziodoxoles and pseudobenziodoxoles are powerful electrophiles and mild oxidants toward various unsaturated compounds. In particular, pseudocyclic benziodoxole-derived triflate (IBA-OTf) is an efficient reagent for oxidative heteroannulation reactions. Aldoximes react with nitriles in the presence of IBA-OTf at room temperature to give 1,2,4-oxadiazoles in high yields. Moreover, IBA-triflate is used as a catalyst in oxidative heteroannulations with m-chloroperoxybenzoic Acid as the terminal oxidant. The iodine(V) benziodoxole derived tosylates, DMP-tosylate and IBX-tosylate, are superior oxidants for the oxidation of structurally diverse, synthetically useful alcohols, utilized as key precursors in the total syntheses of polyketide antibiotics and terpenes. And finally, the most powerful hypervalent iodine(V) oxidant, 2-Iodoxybenzoic Acid ditriflate (IBX·2HOTf), is prepared by treatment of IBX with trifluoromethanesulfonic Acid. According to the X-ray data, the I–OTf bonds in IBX-ditriflate have ionic character, leading to the high reactivity of this reagent in various oxidations. In particular, IBX-ditriflate can oxidize polyfluorinated primary alcohols, which are generally extremely resistant to oxidation.1 Introduction2 Iodine(III) Benziodoxole Based Organosulfonates3 Pseudocyclic Iodine(III) Benziodoxole Triflate (IBA-triflate)4 Pseudocyclic Iodine(III) Benziodoxole Tosylates5 Iodine(V) Benziodoxole Derived Tosylates6 Iodine(V) Benziodoxole Derived Triflate (IBX-ditriflate)7 Conclusions
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2-Iodoxybenzoic Acid ditriflate: the most powerful hypervalent iodine(V) oxidant
Chemical Communications, 2019Co-Authors: Mekhman S. Yusubov, Natalia S. Soldatova, Pavel S. Postnikov, Rashid R. Valiev, Akira Yoshimura, Thomas Wirth, Victor N. Nemykin, Viktor V. ZhdankinAbstract:A ditriflate derivative of 2-Iodoxybenzoic Acid (IBX) was prepared by the reaction of IBX with trifluoromethanesulfonic Acid and characterized by single crystal X-ray crystallography. IBX-ditriflate is the most powerful oxidant in a series of structurally similar IBX derivatives which is best illustrated by its ability to readily oxidize hydrocarbons and the oxidation resistant polyfluoroalcohols.
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2-Iodoxybenzoic Acid Tosylates: the Alternative to Dess–Martin Periodinane Oxidizing Reagents
Advanced Synthesis & Catalysis, 2017Co-Authors: Mekhman S. Yusubov, Pavel S. Postnikov, Akira Yoshimura, Roza Ya. Yusubova, Gerrit Jürjens, Andreas Kirschning, Viktor V. ZhdankinAbstract:Two powerful hypervalent iodine(V) oxidants, DMP-OTs (1-tosyloxy-1,1-diacetoxy-1H-1λ5-benzo[d][1,2]iodoxol-3-one) and IBX-OTs (1-tosyloxy-1-oxo-1H-1λ5-benzo[d][1,2]iodoxol-3-one) show high reactivity in the oxidation of structurally complex primary and secondary alcohols, which are highly functionalized polyketide or terpene fragments or steroids. The yields of the corresponding carbonyl compounds are even higher for the protocol that uses pyridine as additive. The oxidations proceed very rapidly at room temperature leaving the protective groups and π-systems intact and affording the corresponding carbonyl compounds in good to excellent yields. Moreover, IBX-OTs is an efficient reagent for the oxidative dehydrogenation of steroidal alcohols to the corresponding enones.
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2-Iodoxybenzoic Acid Organosulfonates: Preparation, X-Ray Structure and Reactivity of New, Powerful Hypervalent Iodine(V) Oxidants.
ChemInform, 2014Co-Authors: Mekhman S. Yusubov, Akira Yoshimura, Victor N. Nemykin, Dmitrii Yu. Svitich, Viktor V. ZhdankinAbstract:New hypervalent iodine(V) oxidants are prepared by the reaction of IBX with sulfonic Acids.
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2-Iodoxybenzoic Acid organosulfonates: preparation, X-ray structure and reactivity of new, powerful hypervalent iodine(V) oxidants.
Chemical Communications, 2013Co-Authors: Mekhman S. Yusubov, Akira Yoshimura, Victor N. Nemykin, Dmitrii Yu. Svitich, Viktor V. ZhdankinAbstract:New powerful hypervalent iodine(V) oxidants, tosylate and mesylate derivatives of 2-Iodoxybenzoic Acid (IBX), were prepared by the reaction of IBX with the corresponding sulfonic Acids. Single crystal X-ray crystallography of the diacetate derivative of IBX-tosylate revealed an unusual heptacoordinated iodine geometry without any significant intermolecular secondary interactions.
Q.a Wang - One of the best experts on this subject based on the ideXlab platform.
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Controllable and efficient oxidation of thioether by 2-Iodoxybenzoic Acid (IBX) in water: Semisynthesis of sophocarpine
Tetrahedron Letters, 2014Co-Authors: Chaojie Li, Yuxiu Liu, Q.a WangAbstract:A metal-free, environment friendly, easy-to-operate, and efficient method for the semisynthesis of sophocarpine from matrine has been developed in an overall yield of 91%. The route features a controllable and efficient oxidation of thioether to sulfoxide by 2-Iodoxybenzoic Acid (IBX) in water. ?? 2014 Elsevier Ltd. All rights reserved.
Chaojie Li - One of the best experts on this subject based on the ideXlab platform.
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Controllable and efficient oxidation of thioether by 2-Iodoxybenzoic Acid (IBX) in water: semisynthesis of sophocarpine
Tetrahedron Letters, 2014Co-Authors: Chaojie Li, Qingmin WangAbstract:A metal-free, environment friendly, easy-to-operate, and efficient method for the semisynthesis of sophocarpine from matrine has been developed in an overall yield of 91%. The route features a controllable and efficient oxidation of thioether to sulfoxide by 2-Iodoxybenzoic Acid (IBX) in water.
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Controllable and efficient oxidation of thioether by 2-Iodoxybenzoic Acid (IBX) in water: Semisynthesis of sophocarpine
Tetrahedron Letters, 2014Co-Authors: Chaojie Li, Yuxiu Liu, Q.a WangAbstract:A metal-free, environment friendly, easy-to-operate, and efficient method for the semisynthesis of sophocarpine from matrine has been developed in an overall yield of 91%. The route features a controllable and efficient oxidation of thioether to sulfoxide by 2-Iodoxybenzoic Acid (IBX) in water. ?? 2014 Elsevier Ltd. All rights reserved.
Roberta Bernini - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Biologically Active Catecholic Compounds via ortho-Selective Oxygenation of Phenolic Compounds Using Hypervalent Iodine(V) Reagents
Current Organic Synthesis, 2012Co-Authors: Roberta Bernini, Giancarlo Fabrizi, Laurent Pouységu, Denis Deffieux, Stéphane QuideauAbstract:A review. Catecholic motifs are present in numerous natural products and synthetic compds. used in various sectors of the chem. industries such as food, cosmetic, pharmaceutical and polymer industries. The antioxidant activity usually conferred to compds. bearing catecholic motifs is the property on which their application is often based. Although several (bio) chem. methods are available to chemists to produce catechols, the oxygenation of phenols constitutes one of the most practical approaches as long as the o-selectivity of the process can be controlled. In this context, oxygenating hypervalent iodine(V) reagents offer a convenient metal-free soln. Among these reagents, 2-iodoxybenzoic Acid (IBX) or its stabilized (non explosive) SIBX and polymer-supported versions have found the most useful and successful applications in the conversion of phenols into o-quinones, followed by redn. into catechols. Examples of oxygenative demethylation of 2-methoxyphenols and o-hydroxylation of phenolic compds. for the synthesis of biol. and industrially-relevant catechols are highlighted in this review article, together with some mechanistic discussions on these transformations
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Synthesis and Structure/Antioxidant Activity Relationship of Novel Catecholic Antioxidant Structural Analogues to Hydroxytyrosol and Its Lipophilic Esters
Journal of Agricultural and Food Chemistry, 2012Co-Authors: Roberta Bernini, Maurizio Barontini, Fernanda Crisante, Daniela Tofani, Valentina Balducci, Augusto GambacortaAbstract:A large panel of novel catecholic antioxidants and their fatty Acid or methyl carbonate esters has been synthesized in satisfactory to good yields through a 2-Iodoxybenzoic Acid (IBX)-mediated aromatic hydroxylation as the key step. The new catechols are structural analogues of naturally occurring hydroxytyrosol (3,4-DHE). To evaluate structure/activity relationships, the antioxidant properties of all catecholic compounds were evaluated in vitro by ABTS assay and on whole cells by DCF fluorometric assay and compared with that of the corresponding already known hydroxytyrosyl derivatives. Results outline that all of the new catechols show antioxidant capacity in vitro higher than that of the corresponding hydroxytyrosyl derivatives. Less evident positive effects have been detected in whole cells experiments. Cytotoxicity experiments, using MTT assay, on a representative set of compounds evidenced no influence in cell survival.
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Convenient Synthesis of 1-Aryl-dihydroxyisochromans Exhibiting Antioxidant Activity
Current Organic Chemistry, 2012Co-Authors: Roberta Bernini, Fernanda Crisante, Giancarlo Fabrizi, Patrizia GentiliAbstract:Several 1-aryl-hydroxy and dihydroxyisochromans were synthesized by a two-steps procedure based on the oxa-Pictet-Spengler reaction performed for the first time in dimethyl carbonate (DMC) from phenethyl alcohols and substituted benzaldehydes followed by the regioselective aromatic hydroxylation/oxidative aromatic demethylation with 2-Iodoxybenzoic Acid (IBX)/sodium dithionite (Na2S2O4) system. Some of them showed a novel pattern of hydroxylation degree into A ring. All synthesized isochromans were tested about their radical scavenging activity by 2,2-diphenyl-2-picrylhydrazyl radical (DPPH center dot) method. Experimental results showed that dihydroxyisochromans were more active than the corresponding phenolic or guaiacolic parent compounds confirming the key role of the catecholic moiety for the antioxidant activity
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Selective and Efficient Oxidative Modifications of Flavonoids with 2-Iodoxybenzoic Acid (IBX).
ChemInform, 2010Co-Authors: Maurizio Barontini, Roberta Bernini, Fernanda Crisante, Giancarlo FabriziAbstract:A regioselective aromatic hydroxylation of a variety of flavanones and flavones using IBX or a polystyrene-supported IBX is demonstrated.
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Selective and efficient oxidative modifications of flavonoids with 2-Iodoxybenzoic Acid (IBX)
Tetrahedron, 2010Co-Authors: Maurizio Barontini, Roberta Bernini, Fernanda Crisante, Giancarlo FabriziAbstract:Abstract 2-Iodoxybenzoic Acid (IBX), a mild and efficient hypervalent iodine oxidant, has been utilised in different reaction conditions to perform several efficient oxidative modifications of flavonoids. Fine-tuning of the reaction conditions allowed remarkably selective modifications of these compounds. At room temperature, IBX proved to be an excellent reagent for a highly regioselective aromatic hydroxylation of monohydroxylated flavanones and flavones, generating the corresponding catecholic derivatives showing high antioxidant activity. At 90 °C, IBX efficiently dehydrogenated a large panel of methoxylated flavanones to their corresponding flavones exhibiting anticancer activity. IBX polystyrene has also been utilised to increase the recovery of highly polar compounds. Following the first oxidation, the reagent was recovered and reused in several runs without loss of efficiency and selectivity. The first example of an application of IBX polystyrene in a dehydrogenation reaction has been described.
Jarugu Narasimha Moorthy - One of the best experts on this subject based on the ideXlab platform.
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One-Pot Synthesis of 4-Carboalkoxy-Substituted Benzo[h]coumarins from α- and β-Naphthols and Their Excited-State Properties.
ACS omega, 2019Co-Authors: Ajeet Chandra, Kanyashree Jana, Jarugu Narasimha MoorthyAbstract:One-pot synthesis has been developed for 4-carboethoxybenzo[h]coumarins starting from α-/β-naphthols. Accordingly, diverse 4-carboethoxybenzocoumarins can be synthesized in moderate-to-excellent (31–75%) isolated yields. The synthesis involves initial oxidation of naphthols to the intermediary 1,2-naphthoquinones with 2-Iodoxybenzoic Acid followed by a cascade of reactions, namely, Wittig olefination, Michael addition, β-elimination, and cyclization. Furthermore, we have comprehensively investigated the excited-state properties of differently substituted 4-carboalkoxybenzo[h]coumarins. It is shown that they exhibit low to high fluorescence quantum yields (1–36%) and excited-state lifetimes (ca. 1–7 ns) depending on the substitution pattern and solvent employed.
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One-pot synthesis of α-bromo- and α-azidoketones from olefins by catalytic oxidation with in situ-generated modified IBX as the key reaction
Tetrahedron, 2017Co-Authors: Ajeet Chandra, Keshaba Nanda Parida, Jarugu Narasimha MoorthyAbstract:Abstract Simple one-pot protocols for the syntheses of α-bromoketones and α-azidoketones starting from olefins have been developed by employing catalytic oxidation of the intermediary bromohydrins with in situ-generated modified IBX as the key reaction. The improved procedure involves initial formation of bromohydrin by the reaction of olefin with NBS in acetonitrile-water mixture (1:1) at rt followed by oxidation with in situ-generated 3,4,5,6-tetramethyl-2-Iodoxybenzoic Acid (TetMe-IBX), produced in catalytic amounts from 3,4,5,6-tetramethyl-2-iodobenzoic and Oxone. α-Bromoketones are further converted in the same pot to the corresponding α-azidoketones using NaN3/NaHCO3. The one-pot conversions are versatile for a variety of olefins that include cyclic as well as acyclic aliphatic olefins and electron-rich and electron-deficient styrenes. Chemoselective bromohydroxylation of electron-rich double bond and subsequent oxidation to the α-bromoketone is demonstrated for a substrate that contains both electron-rich and deficient double bonds.
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Oxidative Cleavage of Olefins by in situ-Generated Catalytic 3,4,5,6-Tetramethyl-2-Iodoxybenzoic Acid/Oxone.
ChemInform, 2015Co-Authors: Jarugu Narasimha Moorthy, Keshaba Nanda ParidaAbstract:The reaction mechanism is described as initial dihydroxylation of the olefin with oxone, oxidative cleavage by in situ-generated 3,4,5,6-tetramethyl-2-Iodoxybenzoic Acid, and subsequent oxidation of the aldehyde functionality to the corresponding Acid with oxone again.
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Oxidative cleavage of olefins by in situ-generated catalytic 3,4,5,6-tetramethyl-2-Iodoxybenzoic Acid/oxone.
Journal of Organic Chemistry, 2014Co-Authors: Jarugu Narasimha Moorthy, Keshaba Nanda ParidaAbstract:Oxidative cleavage of a variety of olefins to the corresponding ketones/carboxylic Acids is shown to occur in a facile manner with 3,4,5,6-tetramethyl-2-iodobenzoic Acid (TetMe-IA)/oxone. The simple methodology involves mere stirring of the olefin and catalytic amount (10 mol %) of TetMe-IA and oxone in acetonitrile–water mixture (1:1, v/v) at rt. The reaction mechanism involves initial dihydroxylation of the olefin with oxone, oxidative cleavage by the in situ-generated 3,4,5,6-tetramethyl-2-Iodoxybenzoic Acid (TetMe-IBX), and oxidation of the aldehyde functionality to the corresponding Acid with oxone. Differences in the reactivities of electron-rich and electron-poor double bonds have been exploited to demonstrate chemoselective oxidative cleavage in substrates containing two double bonds.