Selective oxidation of sulfides and oxidative bromination of organic substrates catalyzed by polymer anchored Cu(II) complex

Islam, Sk. Manirul; Roy, Anupam Singha; Mondal, Paramita; Tuhina, Kazi; Mobarak, Manir; Mondal, John

doi:10.1016/j.tetlet.2011.10.138

Cited by 64 publications

(11 citation statements)

References 42 publications

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“…The switched regioselectivity in THF could be clarified by the fact that the bromination of aniline (1a) efficiently occurred in the presence of 30% aqueous H 2 O 2 within 2 h, delivering 4-bromoaniline (1d) in 92% yield, while only 16% yield of 1d was obtained with DMF as the solvent (Scheme 4d). 54,55 As for the Pd-catalyzed dehydrogenative aminohalogenation of alkenes, the above results were inconsistent with those when 5 atm of O 2 was used as the sole oxidant in our previous report, illustrating that different mechanisms might be involved in these two reaction systems. We speculated that (Z)-enamine (5) might be a key intermediate of the transformation in this co-oxidative catalytic system.…”

Section: ■ Results and Discussioncontrasting

confidence: 75%

Palladium-Catalyzed Oxidative C–N Bond Coupling Involving a Solvent-Controlled Regioselective Bromination Process

Huang

Xiong

et al. 2014

J. Org. Chem.

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Stereoselective palladium-catalyzed oxidative C-N bond coupling reactions between aromatic amines and alkenes involving a solvent-controlled regioselective bromination process under 1 atm of oxygen atmosphere are disclosed, providing easy access to two different brominated enamines. The addition of hydrogen peroxide (30% aq) as a co-oxidant in the system is crucial for the dehydrogenative aminohalogenation under molecular oxygen (1 atm), and in such a case, the C-N bond coupling/electrophilic bromination reaction cascade is proposed. Furthermore, the different reaction media leads to a switched regioselectivity of the process.

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Section: ■ Results and Discussioncontrasting

confidence: 75%

Palladium-Catalyzed Oxidative C–N Bond Coupling Involving a Solvent-Controlled Regioselective Bromination Process

Huang

Xiong

et al. 2014

J. Org. Chem.

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“…Vanadium complexes Cs(H 2 O)[V V O 2 {3,5‐bis(2‐hydroxyphenyl)‐1‐phenyl‐ 1,2,4‐triazole}] gave 99% conversion, and dioxidovanadium(V) complex [K(H 2 O) 2 ][VO 2 L] (H 2 L=ligands derived from condensation of 4,6‐diacetyl resorcinol and various hydrazides gave 89–98% conversion while dioxidomolybdenum(VI) complexes derived from the condensation of 8‐formyl‐7‐hydroxy‐4‐methylcoumarin with hydrazides gave 94–99% conversion of thymol (a monoterpene phenol) . Polymer anchored Cu(II) complexes, have been reported to give 96% conversion of phenol in 2.5 h along with 100% selectivity of 4‐bromophenol which clearly remarks the importance of newly synthesized vanadium(V) and molybdenum(VI) complexes as efficient catalyst for oxidative bromination reactions.…”

Section: Resultsmentioning

confidence: 99%

Vanadium(V) and Molybdenum(VI) Complexes Containing ONO Tridentate Schiff Bases and Their Application as Catalysts for Oxidative Bromination of Phenols

et al. 2019

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Condensation of 2,4‐dihydroxyacetophenone with isonicotinoyl hydrazide and nicotinoyl hydrazide in an equimolar ratio in methanol results in the formation of two stable ONO donor ligands, H2dhap‐inh (I) and H2dhap‐nah (II), respectively. These ligands react with [VIVO(acac)2] (Hacac=acetylacetone) in 1:1 molar ratio to give the corresponding neutral dioxidovanadium(V) complexes, [VVO2(Hdhap‐inh)] (1) and [VVO2(Hdhap‐nah)] (2), after overnight aerial oxidation in the presence of K2CO3. In the absence of K2CO3, they result in (μ‐O){bisoxidovanadium(V)} complexes, [{VVO(dhap‐inh)}2(μ‐O)] (3) and [{VVO(dhap‐nah)}2(μ‐O)] (4). Treatment of neutral dioxidovanadium(V) complexes, 1 and 2, with H2O2 yields oxidoperoxidovanadium(V) complexes K[VVO(O2)(dhap‐inh)(H2O)] (5) and K[VVO(O2)(dhap‐nah)(H2O)] (6). The ligands also react with [MoVIO2(acac)2] in 1:1 molar ratio to form [MoVIO2(dhap‐inh)]n (7) and [MoVIO2(dhap‐nah)]n (8). The reaction of oxidoperoxidomolybdenum(VI) species, generated in situ by the reaction of MoO3 with H2O2 with ligands I and II, gives the oxidoperoxidomolybdenum(VI) complexes, [MoVIO(O2)(dhap‐inh)(MeOH)] (9) and [MoVIO(O2)(dhap‐nah)(MeOH)] (10), respectively. All synthesized complexes are characterized by elemental analysis, thermogravimetric, electrochemical, spectroscopic (IR, UV–Vis, 1H, 13C and 51V NMR) and single crystal X‐ray diffraction (for 1, 2 and 8). Complexes are explored as catalysts for the oxidative bromination of phenol, a model oxidative halogenation reaction, in the presence of HClO4 and KBr, using 30% H2O2 as oxidant. Under optimized reaction conditions, the product selectivity follows the order: 4‐bromophenol>2‐bromophenol, both for molybdenum and vanadium complexes. Products characterized by GC analysis showed very good conversion of phenol.

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“…Since heterogeneous vanadium catalysts exhibit significant activity in various oxidation reactions, so we have investigated the potential activity of this polymer supported oxo‐ vanadium(IV) catalyst in the oxidation of toluene. At first, reaction conditions for the activation of benzylic C−H bonds of toluene were varied and optimized by means of different experimental conditions such as various solvents and oxidants, amount of catalyst and temperature.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Characterization and Catalytic Studies of Heterogeneous Oxo‐Vanadium(IV) Schiff base Catalyst for Activation of Benzylic C‐H bonds of Alkanes

et al. 2016

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Here, polymer grafted vanadium(IV) Schiff base catalyst was prepared and applied in the oxidation of benzylic C‐H bonds of alkanes. The solid complex was characterized by some modern techniques i. e. FT‐IR, TGA, SEM‐EDX and solid state UV‐Vis spectroscopy (DRS). This heterogeneous complex showed excellent activity for the oxidation of toluene to benzaldehyde using 30% H2O2 as an oxidantin acetonitrile (ACN) medium at 70oC. This vanadium catalyst was also active for the oxidation of various substituted toluenes. It showed good conversion as well as selectivity for the production of aldehydes from alkanes. The reported catalyst was easily recovered and reused for at least eight times with similar activity.

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Selective oxidation of sulfides and oxidative bromination of organic substrates catalyzed by polymer anchored Cu(II) complex

Cited by 64 publications

References 42 publications

Palladium-Catalyzed Oxidative C–N Bond Coupling Involving a Solvent-Controlled Regioselective Bromination Process

Palladium-Catalyzed Oxidative C–N Bond Coupling Involving a Solvent-Controlled Regioselective Bromination Process

Vanadium(V) and Molybdenum(VI) Complexes Containing ONO Tridentate Schiff Bases and Their Application as Catalysts for Oxidative Bromination of Phenols

Synthesis, Characterization and Catalytic Studies of Heterogeneous Oxo‐Vanadium(IV) Schiff base Catalyst for Activation of Benzylic C‐H bonds of Alkanes

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