- A sustainable approach towards solventless organic oxidations catalyzed by polymer immobilized Nb(V)-peroxido compounds with H2O2 as oxidant
-
New heterogeneous catalysts comprising of peroxidoniobium(V) complexes immobilized on amino acid grafted cross-linked poly(styrene-divinylbenzene) resin has been developed. Results of FTIR, Raman, NMR, XPS, XRD, EDX, SEM, BET, TGA, and elemental analysis confirmed the successful anchoring of triperoxidoniobium(V), [Nb(O2)3]? species to the host polymer via the pendant amino acid groups. The supported catalysts exhibited excellent performance in epoxidation of styrene and a range of cyclic and terpenic compounds under environmentally acceptable solvent-free condition, with aqueous H2O2 as oxidant. The catalytic protocols provided excellent conversion to the desired epoxide (up to 100%) with selectivity > 99%, TON as high as 1000, and high H2O2 utilization efficiency (92–97%). Moreover, the catalysts efficiently facilitated chemoselective solvent-free oxidation of a variety of thioethers to sulfones at room temperature. Simple operational strategy, easy recyclability for multiple reaction cycles with the consistent activity-selectivity profile are the additional significant attributes of the developed catalytic processes.
- Ahmed, Kabirun,Gogoi, Sandhya Rani,Islam, Nashreen S.,Saikia, Gangutri,Sultana, Sazida Yasmin,Talukdar, Hiya
-
-
- Selective synthesis of sulfoxides and sulfonesviacontrollable oxidation of sulfides withN-fluorobenzenesulfonimide
-
A practical and mild method for the switchable synthesis of sulfoxides or sulfonesviaselective oxidation of sulfides using cheapN-fluorobenzenesulfonimide (NFSI) as the oxidant has been developed. These highly chemoselective transformations were simply achieved by varying the NFSI loading with H2O as the green solvent and oxygen source without any additives. The good functional group tolerance makes the strategy valuable.
- Cao, Zhong-Yan,Li, Xiaolong,Lu, Hao,Wang, Panpan,Wang, Shengqiang,Xu, Xiaobo,Yan, Leyu,Yang, A-Xiu
-
supporting information
p. 8691 - 8695
(2021/10/22)
-
- Metal-free visible-light-promoted C(sp3)-H functionalization of aliphatic cyclic ethers using trace O2
-
Presented is a light-promoted C-C bond forming reaction yielding sulfone and phosphate derivatives at room temperature in the absence of metals or photoredox catalyst. This transformation proceeds in neat conditions through an auto-oxidation mechanism which is maintained through the leaching of trace amounts of O2 as sole green oxidant. This journal is
- Blackburn, Bryan G.,Cooke, Maria Victoria,Laulhé, Sébastien,Niu, Ben,Sachidanandan, Krishnakumar
-
supporting information
p. 9454 - 9459
(2021/12/09)
-
- Ruthenium(II)-Catalyzed Highly Chemo- And Regioselective Oxidative C6 Alkenylation of Indole-7-carboxamides
-
We disclosed the first efficient method for highly chemo- and regioselective C6 alkenylation of indole-7-carboxamides using inexpensive Ru(II) catalyst through chelation assisted C-H bond activation. Electronically diverse indole-7-carboxamides and alkenes react efficiently to produce a wide range of C6 alkenyl indole derivatives. Further the C6 alkenyl indole-7-carboxamides modified to their derivatives through simple chemical transformations. The observed regioselectivity and kinetics has been evidenced by deuterium incorporation and intermolecular competitive studies. In addition, for mechanistic insights, the intermediates were analyzed by HRMS.
- Jadhav, Pankaj P.,Kahar, Nilesh M.,Dawande, Sudam G.
-
supporting information
p. 8673 - 8677
(2021/11/20)
-
- Surface decorated magnetic nanoparticles with Mn-porphyrin as an effective catalyst for oxidation of sulfides
-
Mn-porphyrin complex was anchored coordinatively to silica-coated surface of magnetic nanoparticles (SMNP). Afterward, a heterogeneous nanocatalyst (Fe3O4@SiO2-MnTCPP) has been characterized by Fourier transform infrared (FT-IR), ultraviolet-visible (UV-vis) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), and transmission electron microscope (TEM). A thermal stability up to around 350°C was verified for prepared nanocatalyst based on thermogravimetric analysis. Finally, the catalytic performance of magnetically recoverable Mn-catalyst was exploited in the green oxidation of different sulfides with urea hydrogen peroxide (UHP) in the presence of imidazole as co-catalyst in ethanol under heterogeneous conditions. The eco-friendly property of ethanol strongly induced us to employ it as the reaction solvent in this oxidation system. Complete conversion (≥99) of sulfides to the corresponding sulfoxide or sulfones was obtained for ethyl phenyl sulfide, phenyl vinyl sulfide, diallyl sulfide, thiocyanatoethane, 2-ethyl mercaptoethanol and tetrahydrothiophene. Moreover, the recovered catalysts keep constant conversion yield up to at least three cycles.
- Rayati, Saeed,Shokoohi, Saeedeh
-
-
- Continuous bioinspired oxidation of sulfides
-
A simple, efficient, and selective oxidation under flow conditions of sulfides into their corresponding sulfoxides and sulfones is reported herein, using as a catalyst perselenic acid generated in situ by the oxidation of selenium (IV) oxide in a diluted aqueous solution of hydrogen peroxide as the final oxidant. The scope of the proposed methodology was investigated using aryl alkyl sulfides, aryl vinyl sulfides, and dialkyl sulfides as substrates, evidencing, in general, a good applicability. The scaled-up synthesis of (methylsulfonyl)benzene was also demonstrated, leading to its gram-scale preparation.
- Crociani, Letizia,Mangiavacchi, Francesca,Marini, Francesca,Sancineto, Luca,Santi, Claudio
-
-
- Sulfoxidation inside a hypercrosslinked microporous network nanotube catalyst
-
In the present work, a kind of efficient heterogeneous catalyst was synthesized from amine-functionalized hypercrosslinked bottlebrush copolymers of microporous network nanotubes (amine-MNNs) and Na2WO4. The synthesized tungstate-supported microporous network nanotubes (TMNNs) catalyst was shown to be highly active in the selective H2O2 oxidation of sulfides to sulfoxides or sulfones under mild conditions due to the high specific surface area (800 m2 g-1) and firm structure of the nanotubes. The catalyst was found to be very stable and could be recycled at least 8 times without any significant loss of activity. These results present a new opportunity for the development of efficient green organic catalytic materials with high activity.
- Shi, Zhaocheng,Ying, Zhong,Yang, Liusai,Meng, Xiaoyan,Wu, Lidan,Yu, Leshu,Huang, Sen,Xiong, Linfeng
-
supporting information
p. 1542 - 1547
(2020/02/06)
-
- Water-soluble polymer anchored peroxotitanates as environmentally clean and recyclable catalysts for mild and selective oxidation of sulfides with H2O2 in water
-
Anchoring of peroxotitanium (pTi) species to linear water-soluble acrylic acid based polymers, poly(sodium acrylate) (PA) and poly(sodium methacrylate) (PMA) led to the successful synthesis of a pair of new, water-tolerant and recyclable catalysts of the type [Ti2(O2)2O2(OH)2]4-—L (L = PA or PMA), highly effective in chemoselective sulfoxidation of organic sulfides with 30% H2O2 in aqueous medium at ambient temperature. The catalytic protocol is high yielding (TOF up to 11,280 h?1), operationally simple as well as environmentally clean and safe, being free from halide, or any other toxic auxiliaries. The catalysts are sufficiently stable to afford easy recyclability for at least 10 consecutive reaction cycles of sulfoxidation with consistent activity selectivity profile. Oxidation of dibenzothiophene (DBT) to respective high purity sulfoxide or sulfone could also be accomplished using the same catalysts by variation of reaction conditions.
- Ahmed, Kabirun,Saikia, Gangutri,Paul, Sivangi,Baruah, Satyajit Dey,Talukdar, Hiya,Sharma, Mitu,Islam, Nashreen S.
-
-
- Safe and Metal-Free Synthesis of 1-Alkenyl Aryl Sulfides and Their Sulfones from Thiiranes and Diaryliodonium Salts
-
A series of 1-alkenyl aryl sulfides was synthesized from thiiranes and diaryliodonium salts in tetrahydrofuran in the presence of potassium tert -butoxide. The proposed reaction mechanism involves generation of benzynes from the diaryliodonium salts in the presence of the base. Then, nucleophilic attack of the benzynes by thiiranes, followed by hydrogen abstraction and ring opening of the generated thiiranium intermediates, provides the sulfides. These sulfides were further oxidized with performic acid to the corresponding sulfones. The current method provides a metal-free and safe method for the preparation of 1-alkenyl aryl sulfides and their sulfones.
- Dong, Jun,Xu, Jiaxi
-
p. 2407 - 2415
(2018/04/16)
-
- A convenient synthesis of (E)-conjugated polyene sulfonyl derivatives with excellent stereospecificity
-
A highly selective synthesis of conjugated polyene sulfonyl derivatives is described via the elimination of disulfonyl chloride with readily accessible raw material dihaloalkane. The protocol offers a convenient way to form sulfonamides, sulfonates and even sulfones. Furthermore, this method was manipulated under mild condition with simple operation in high yield to afford only trans products.
- Yu, Chunyan,Lv, Zhongwen,Xu, Sheng,Zhang, Jun
-
supporting information
p. 3234 - 3237
(2018/07/25)
-
- Cobalt(II)-based Metalloradical Activation of 2-(Diazomethyl)pyridines for Radical Transannulation and Cyclopropanation
-
A new catalytic method for the denitrogenative transannulation/cyclopropanation of in-situ-generated 2-(diazomethyl)pyridines is described using a cobalt-catalyzed radical-activation mechanism. The method takes advantage of the inherent properties of a CoIII-carbene radical intermediate and is the first report of denitrogenative transannulation/cyclopropanation by a radical-activation mechanism, which is supported by various control experiments. The synthetic benefits of the metalloradical approach are showcased with a short total synthesis of (±)-monomorine.
- Roy, Satyajit,Das, Sandip Kumar,Chattopadhyay, Buddhadeb
-
supporting information
p. 2238 - 2243
(2018/02/19)
-
- Difluoro- and trifluoro diazoalkanes-complementary approaches in batch and flow and their application in cycloaddition reactions
-
Herein we report on applications of fluorinated diazoalkanes in cycloaddition reactions, with the emphasis on studying subtle differences between diverse fluorinated diazo compounds. These differences led to two major synthetic protocols in batch and flow that allow the safe and scalable synthesis of fluoroalkyl-, sulfone-substituted pyrazolines.
- Hock, Katharina J.,Mertens, Lucas,Metze, Friederike K.,Schmittmann, Clemens,Koenigs, Rene M.
-
supporting information
p. 905 - 909
(2017/08/14)
-
- The catalytic efficiency of Fe-porphyrins supported on multi-walled carbon nanotubes in the oxidation of olefins and sulfides with molecular oxygen
-
A Fe-porphyrin catalyst was anchored covalently onto functionalized multi-walled carbon nanotubes. The heterogeneous catalyst was characterized by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, FTIR, UV-Vis spectroscopy and thermogravimetric analysis (TGA). The catalyst loading on the nanotube support was determined by atomic absorption spectroscopy (AAS). The aerobic oxidation of olefins and sulfides under ambient conditions was efficiently enhanced under the influence of the separable nanocatalyst. This oxidation system was found to oxidize various sulfides to sulfones and different olefins to their respective epoxides as major products. Aerobic oxidation generally requires high temperatures and/or long reaction times to occur. However, in this research, the aerobic oxidation of olefins and sulfides was studied in the presence of Fe-porphyrin which was immobilized onto multi-wall carbon nanotubes at room temperature and with a short reaction time of 60 min. The separation and recycling of the catalyst and the byproduct of the oxidant were simple, effective, and economic in this clean oxidation method. FTIR and leaching experiments after seven successive cycles showed that the catalyst was very strongly anchored to the carbon nanotubes.
- Rayati, Saeed,Nejabat, Fatemeh
-
supporting information
p. 7987 - 7991
(2017/08/15)
-
- An environmentally benign and selective electrochemical oxidation of sulfides and thiols in a continuous-flow microreactor
-
A practical and environmentally benign electrochemical oxidation of thioethers and thiols in a commercially-available continuous-flow microreactor is presented. Water is used as the source of oxygen to enable the oxidation process. The oxidation reaction utilizes the same reagents in all scenarios and the selectivity is solely governed by the applied potential. The procedure exhibits a broad scope and good functional group compatibility providing access to various sulfoxides (15 examples), sulfones (15 examples) and disulfides (6 examples). The use of continuous flow allows the optimal reaction parameters (e.g. residence time, applied voltage) to be rapidly assessed, to avoid mass- and heat-transfer limitations and to scale the electrochemistry.
- Laudadio, Gabriele,Straathof, Natan J. W.,Lanting, Menno D.,Knoops, Benny,Hessel, Volker,No?l, Timothy
-
supporting information
p. 4061 - 4066
(2017/09/07)
-
- Enantioselective Aromatic Sulfide Oxidation and Tandem Kinetic Resolution Using Aqueous H2O2 and Chiral Iron–Bis(oxazolinyl)bipyridine Catalysts
-
An efficient method for the oxidation of aromatic sulfides has been developed by using aqueous H2O2, catalyzed by the in situ generated chiral Fe/6,6′-bis(4-isopropyloxazolin-2-yl)-2,2′-bipyridine (bipybox-iPr) complex. The corresponding sulfoxides were obtained with high enantioselectivities (up to 98.5:1.5 er) and in good yields (up to 61 %) when the mono-oxidation of the sulfides was performed in combination with the kinetic resolution of the sulfoxide into the sulfone.
- Jalba, Angela,Régnier, Noémie,Ollevier, Thierry
-
p. 1628 - 1637
(2017/04/06)
-
- Iridium-Catalyzed Cyclization of Isoxazolines and Alkenes: Divergent Access to Pyrrolidines, Pyrroles, and Carbazoles
-
A heterogeneous iridium-complex-catalyzed N-O-cleaving rearrangement/cyclization of 2,3-dihydroisoxazoles with alkenes has been developed. It provides divergent access to multiple substituted pyrrolidines, pyrroles, and carbazoles. The iridium catalyst remains highly catalytic active after seven cycles. The gram-scale synthesis afforded a carbazole with strong bluish-violet fluorescence.
- Xiao, Zu-Feng,Ding, Ting-Hui,Mao, Sheng-Wei,Shah, Zaher,Ning, Xiao-Shan,Kang, Yan-Biao
-
supporting information
p. 5672 - 5675
(2016/11/17)
-
- Peroxoniobium(v)-catalyzed selective oxidation of sulfides with hydrogen peroxide in water: A sustainable approach
-
An efficient and eco-compatible route for the selective oxidation of a variety of thioethers to the corresponding sulfoxide or sulfone with 30% aqueous H2O2 in water, using newly synthesized peroxoniobium (pNb) complexes as catalysts, is described. The catalysts with formulas Na2[Nb(O2)3(arg)]·2H2O (arg = arginate) (NbA) and Na2[Nb(O2)3(nic)(H2O)]·H2O (nic = nicotinate) (NbN) have been synthesized from the reaction of sodium tetraperoxoniobate with 30% H2O2 and the respective organic ligand in an aqueous medium, and these have been comprehensively characterized by elemental analysis, spectral studies (FTIR, Raman, 1H NMR, 13C NMR and UV-vis), EDX analysis and TGA-DTG analysis. The density functional theory (DFT) method has been used to investigate the structure of the synthesized pNb complexes. The catalysts are physiologically safe and can be reused for at least six reaction cycles without losing their activity or selectivity. The oxidation is chemoselective for sulfides or sulfoxides leaving the C=C or alcoholic moiety unaffected. The developed methodologies, apart from being high yielding and straightforward, are completely free from halogen, organic co-solvent, or co-catalysts.
- Gogoi, Sandhya Rani,Boruah, Jeena Jyoti,Sengupta, Gargi,Saikia, Gangutri,Ahmed, Kabirun,Bania, Kusum K.,Islam, Nashreen S.
-
p. 595 - 610
(2015/02/02)
-
- Efficient cu-catalyzed atom transfer radical addition reactions of fluoroalkylsulfonyl chlorides with electron-deficient alkenes induced by visible light
-
Fluoroalkylsulfonyl chlorides, RfSO2Cl, in which Rf=CF3, C4F9, CF2H, CH2F, and CH2CF3, are used as a source of fluorinated radicals to add fluoroalkyl groups to electron-deficient, unsaturated carbonyl compounds. Photochemical conditions, using Cu mediation, are used to produce the respective α-chloro-β-fluoroalkylcarbonyl products in excellent yields through an atom transfer radical addition (ATRA) process. Facile nucleophilic replacement of the α-chloro substituent is shown to lead to further diverse functionalization of the products.
- Tang, Xiao-Jun,Dolbier, William R.
-
supporting information
p. 4246 - 4249
(2015/04/14)
-
- Direct Photoredox-Catalyzed Reductive Difluoromethylation of Electron-Deficient Alkenes
-
Photoredox-catalyzed reductive difluoromethylation of electron-deficient alkenes was achieved in one step under tin-free, mild and neutral conditions. This protocol affords a facile method to introduce RCF2 (R=H, Ph, Me, and CH2N3) groups at sites β to electron-withdrawing groups. It was found that TTMS (tris(trimethylsilyl)silane) served nicely as both the H-atom donor and the electron donor in the catalytic cycle. Experimental and DFT computational results provided evidence that RCF2 (R=H, Ph, Me) radicals are nucleophilic in nature.
- Tang, Xiao-Jun,Zhang, Zuxiao,Dolbier, William R.
-
supporting information
p. 18961 - 18965
(2016/01/26)
-
- Selective synthesis of sulfoxides and sulfones from sulfides using silica bromide as the heterogeneous promoter and hydrogen peroxide as the terminal oxidant
-
Silica bromide as a heterogeneous promoter and reagent is prepared from the reaction of silica gel with PBr3as a non-hydroscopic, filterable, cheap, and stable yellowish powder that can be stored for months. The results show that silica bromide is a suitable and efficient promoter for the chemoselective oxidation of sulfides to the corresponding sulfoxides or sulfones in the presence of 30% H2O2in acetonitrile. The excellent yields, heterogeneous conditions, simplicity, compatibility with a variety of functionalities, and ease of isolation of the products make our procedure a practical alternative.
- Maleki, Behrooz,Hemmati, Saba,Sedrpoushan, Alireza,Ashrafi, Samaneh Sedigh,Veisi, Hojat
-
p. 40505 - 40510
(2015/02/03)
-
- Chemoselective synthesis of unsymmetrical internal alkynes or vinyl sulfones via palladium-catalyzed cross-coupling reaction of sodium sulfinates with alkynes
-
A highly efficient and mild palladium-catalyzed cross-coupling of sodium sulfinates and alkynes for the selective synthesis of unsymmetrical internal alkynes and vinyl sulfones has been developed. This methodology has advantages of easily accessible starting materials, functional group tolerance and a wide range of substrates, which provides rapid access to alkynes and vinyl sulfones.
- Xu, Yanli,Zhao, Jinwu,Tang, Xiaodong,Wu, Wanqing,Jiang, Huanfeng
-
p. 2029 - 2039
(2014/07/07)
-
- Selectivity reversal during thia-Michael additions using tetrabutylammonium hydroxide: Operationally simple and extremely high turnover
-
The use of tetrabutylammonium hydroxide as a novel and exceedingly efficient thia-Michael addition catalyst is herein described. This extremely simple methodology allows for the conjugate addition of a wide variety of mercaptan nucleophiles, and functions remarkably well with a very wide range of both classical and non-classical Michael acceptors. Contradistinctive to current literature reports, the use of this catalyst more efficiently promotes the addition of more basic thiols. This methodology is especially attractive and operationally simple, as it generally proceeds with only 1 mol% catalytic loading and without excess reagent, and the produced products typically require no purification. Georg Thieme Verlag Stuttgart New York.
- Nicponski, Daniel R.,Marchi, Jennifer M.
-
supporting information
p. 1725 - 1730
(2014/07/08)
-
- Copper-catalyzed aerobic oxidative N-S bond functionalization for C-S bond formation: Regio- and stereoselective synthesis of sulfones and thioethers
-
A regio- and stereoselective synthesis of sulfones and thioethers by means of CuI-catalyzed aerobic oxidative N-S bond cleavage of sulfonyl hydrazides, followed by cross-coupling reactions with alkenes and aromatic compounds to form the C-sp-2-S bond, is described herein. N2 and H2O are the byproducts of this transformation, thus offering an environmentally benign process with a wide range of potential applications in organic synthesis and medicinal chemistry. First cleave, then cross-couple: A direct Cu-catalyzed aerobic oxidative C-sp-2-H functionalization and C-S bond coupling reaction has been developed (see scheme). By slight modification of the additive, sulfonyl hydrazides could serve as sulfonation, sulfenation, or arylation reagents to undergo cross-coupling reactions with alkenes and (hetero)aromatic cycles, affording sulfones, thioethers, and biaryl compounds with high regio- and stereoselectivities (see scheme).
- Li, Xianwei,Xu, Yanli,Wu, Wanqing,Jiang, Chang,Qi, Chaorong,Jiang, Huanfeng
-
supporting information
p. 7911 - 7915
(2014/07/07)
-
- Synthesis, characterization, structure and properties of copper and palladium complexes incorporating azo-amide ligands
-
The reaction of the multidentate ligand N-(2-(aryldiazenyl)phenyl) picolinamide, HL (3a, 3b and 3c) [HL is ArN = NC6H 4NHC(O)Py, where Ar is C6H5 for HL1 (3a), p-MeC6H4 for HL2 (3b) or p-ClC 6H4 for HL3 (3c), and Py stands for pyridyl], with Cu(CH3COO)2·H2O and Na 2PdCl4 separately afforded the complexes [(L) 2Cu] (4a, 4b and 4c) and [(L)PdCl] (5a, 5b and 5c) respectively, where the deprotonated ligand L- binds copper(II) and palladium(II) in a tridentate (N,N,N) fashion. X-ray structures of [(L3) 2Cu] (4c) and [(L1)PdCl] (5a) were determined to confirm the molecular structures. The newly synthesized complex 4a exhibits catalytic activity toward the oxidation of alcohols to the corresponding carbonyl compounds and oxidation of organic thioethers to sulfoxide and sulfone, whereas the complex 5a is an active catalyst for Suzuki and Heck reactions.
- Pattanayak, Poulami,Pratihar, Jahar Lal,Patra, Debprasad,Brand?o, Paula,Felix, Vitor,Chattopadhyay, Surajit
-
-
- Merrifield resin supported peroxomolybdenum(vi) compounds: Recoverable heterogeneous catalysts for the efficient, selective and mild oxidation of organic sulfides with H2O2
-
We have generated new heterogeneous catalysts by immobilizing dioxomonoperoxomolybdenum(vi) on amino acid functionalized Merrifield resin, which exhibit excellent activity, stability and selectivity for the oxidation of thioethers and dibenzothiophene (DBT) to the corresponding sulfoxides or sulfones by H2O2 at ambient temperature. The synthetic protocols are high-yielding, halogen-free, environmentally clean and safe, and operationally simple. The catalysts, [MoO2(O2)(L) 2]2--MR [L = valine (MRVMo) or alanine (MRAMo) and MR = Merrifield resin] were prepared by reacting H2MoO4 with 30% H2O2 and the respective amino acid functionalized resin, at near neutral pH. The compounds were characterized by elemental analysis, spectral studies (FTIR, Raman, 13C NMR and 95Mo NMR, diffuse reflectance UV-Vis and XPS), SEM, EDX, XRD, Brunauer-Emmett-Teller (BET) and TGA-DTG analysis. The easy recyclability of the catalysts for several catalytic cycles without change in activity and selectivity, their complete chemoselectivity towards the sulfur group of substrates bearing other oxidation prone functional groups, are important "green" attributes of these catalysts.
- Boruah, Jeena Jyoti,Das, Siva Prasad,Ankireddy, Seshadri Reddy,Gogoi, Sandhya Rani,Islam, Nashreen S.
-
p. 2944 - 2959
(2013/10/08)
-
- Selective oxidation of bulky sulfides to sulfoxides over titanosilicates having an MWW structure in the presence of H2O2 under organic solvent-free conditions
-
A selective hydrogen peroxide oxidation of sulfides to sulfoxides using Ti-MWW and Ti-IEZ-MWW catalysts was developed. This reaction was carried out under organic solvent-free conditions, and the only side-product was water. Improvement of catalytic activity toward bulky sulfides will be achieved by optimization of the topology in the Ti zeolite.
- Kon, Yoshihiro,Yokoi, Toshiyuki,Yoshioka, Masato,Uesaka, Yumiko,Kujira, Harumi,Sato, Kazuhiko,Tatsumi, Takashi
-
supporting information
p. 4918 - 4921
(2013/09/02)
-
- Selective oxidation of organic sulfides by mononuclear and dinuclear peroxotungsten(VI) complexes
-
Clean conversion of a variety of sulfides and dibenzothiophene (DBT) to the corresponding sulfoxide or sulfone could be achieved in high yields at room temperature using mononuclear as well as dinuclear diperoxo complexes of tungsten as oxidants, by a variation of reaction conditions. The compounds could also effectively catalyze oxidation of sulfides by H2O2 to selectively yield sulfone with reasonably good turnover frequency (TOF).
- Das, Siva Prasad,Boruah, Jeena Jyoti,Chetry, Hiran,Islam, Nashreen S.
-
experimental part
p. 1163 - 1168
(2012/03/26)
-
- New polymer-immobilized peroxotungsten compound as an efficient catalyst for selective and mild oxidation of sulfides by hydrogen peroxide
-
A new polymer-bound peroxotungstate(VI) catalyst of the type [W(O) 2(O2)(CN)2]-PAN [PAN = poly(acrylonitrile)] (PANW) has been prepared by reacting H2WO4 with 30% H 2O2 and the macromolecular ligand, PAN at pH 5.0. The compound was characterized by elemental analysis, SEM, EDX, TGA and spectral studies (FTIR and 13C NMR). Clean conversion of a variety of sulfides and dibenzothiophene (DBT) to the corresponding sulfoxide or sulfone, using H2O2 as oxidant, could be achieved in the presence of the heterogeneous catalyst PANW, by a versatile variation of reaction conditions. The reactions proceed under mild conditions to afford the resulting products with impressive turn over frequency (TOF). The catalyst exhibit complete chemoselectivity toward sulfur group of substituted sulfides with other oxidation prone functional groups. Easy regeneration and reusability of the catalyst for at least up to seven catalytic cycles with consistent activity and selectivity is an important attribute of the catalyst.
- Das, Siva Prasad,Boruah, Jeena Jyoti,Sharma, Niharika,Islam, Nashreen S.
-
experimental part
p. 36 - 45
(2012/04/17)
-
- Aqueous heterogeneous oxygenation of hydrocarbons and sulfides catalyzed by recoverable magnetite nanoparticles coated with copper(ii) phthalocyanine
-
In this work, a novel magnetically recoverable phthalocyanine catalyst was prepared by immobilization of the Cu(ii) phthalocyanine-tetrasulfonic acid tetrasodium complex (CuPcS) on the silica coated magnetic nanoparticles (Fe 3O4@SiO2, SMNP) via the amine functionality (ASMNP). The epoxidation of olefins and the oxidation of saturated hydrocarbons to the related ketones and also sulfides to the sulfones by an aqueous solution of tetra-n-butylammonium peroxomonosulfate (n-Bu4NHSO5, TBAOX) were efficiently enhanced with excellent selectivity under the influence of the catalytic activity of the magnetically separable catalyst. Sulfoxides could also be selectively produced in the mixture of water-ethanol, which makes the title methodology a good alternative for both sulfoxide and sulfone production. The separation and recycling of the catalyst and the reduced form of the oxidant were simple, effective and economical in this clean oxidation method. The FT-IR and leaching experiments after seven successive cycles showed that the catalyst was most strongly anchored to the magnetite nanoparticles.
- Rezaeifard, Abdolreza,Jafarpour, Maasoumeh,Naeimi, Atena,Haddad, Reza
-
p. 3386 - 3394
(2013/01/16)
-
- Efficient and highly selective aqueous oxidation of alcohols and sulfides catalyzed by reusable hydrophobic copper (II) phthalocyanine
-
A practical innovative method for highly chemoselective oxidation of alcohols to the aldehyde and ketones and sulfides to the sulfones using tetra-n-butylammonium peroxomonosulfate (n-Bu4NHSO5) catalyzed by simple water-insoluble copper (II) phthalocyanine (CuPc) in neat water has been developed. Organic co-solvents, surfactants, co-catalyst and hydrophilic auxiliaries were completely missed in this heterogeneous catalytic strategy. The CuPc catalyst and by-product of oxidant (TBAHSO4) could easily be recycled and reused without loss of activity providing readily scalability.
- Rezaeifard, Abdolreza,Jafarpour, Maasoumeh,Naeimi, Atena,Salimi, Mehri
-
experimental part
p. 230 - 234
(2012/02/14)
-
- Highly atom-economic, catalyst- and solvent-free oxidation of sulfides into sulfones using 30% aqueous H2O2
-
Highly atom-efficient oxidation of sulfides into sulfones under solvent- and catalyst-free reaction conditions using a 30% aqueous solution of H 2O2 at 75 °C is reported. A structurally diverse set of phenyl alkyl-, phenyl benzyl-, benzyl alkyl-, dialkyl-, heteroaryl alkyl- and cyclic sulfides were transformed into sulfones regardless of the aggregate state and electronic nature of the substituents. In spite of the heterogeneous reaction mixtures throughout the work, no difficulties with stirring and reaction progress were noted. In numerous cases, only 10 mol% excess of H 2O2 was used, thus contributing considerably to the high atom economy of the process. Some solid substrates required a variable excess of hydrogen peroxide; however, the reactions were performed strictly without organic solvents. The transformation was demonstrated to be amenable for scale-up with both liquid and solid sulfides. In addition, isolation and purification of the crude products can be simply done with only filtration and crystallization.
- Jereb, Marjan
-
supporting information
p. 3047 - 3052,6
(2020/09/16)
-
- Keggin heteropolycompounds as catalysts for liquid-phase oxidation of sulfides to sulfoxides/sulfones by hydrogen peroxide
-
H4PMo11VO40, H5PMo 10V2O40 and H9PMo6V 6O40 acids and an acidic pyridinium salt of H 4PMo11VO40 were synthesized. They were characterized by FT-IR and the variations of their acid properties were determined by titration with n-butylamine. They proved to be highly active and selective catalysts for the hydrogen peroxide oxidation of methyl phenyl sulfide to the corresponding sulfoxide or sulfone. The conversion and selectivity results may be explained in terms of the co-existence of acidic and oxidative properties in the catalysts. On the other hand, a convenient catalytic homogeneous procedure has been found to oxidize different sulfides to sulfoxides or sulfones, with 35% aqueous H2O2, using (PyH)H 3PMo11VO40 as catalyst. The oxidation reaction is carried out at room temperature for sulfoxides or 40 °C for sulfones and requires a short time. The sulfoxides or sulfones were obtained with excellent yields by controlling the amount of H2O2.
- Romanelli, Gustavo P.,Villabrille, Paula I.,Cáceres, Cármen V.,Vázquez, Patricia G.,Tundo, Pietro
-
p. 726 - 730
(2013/01/09)
-
- CONTROLLED DRUG RELEASE FROM SOLID SUPPORTS
-
The invention relates to solid supports useful in medical applications that provide controlled release of drugs, such as peptides, nucleic acids and small molecules. The drugs are covalently coupled to the solid support through a linkage that releases the drug or a prodrug through controlled beta elimination.
- -
-
Page/Page column 31-32
(2011/11/30)
-
- CONTROLLED RELEASE FROM MACROMOLECULAR CONJUGATES
-
The invention relates to conjugates of macromolecular carriers and drugs comprising linkers that release the drug or a prodrug through rate-controlled beta-elimination, and methods of making and using the conjugates.
- -
-
Page/Page column 24-25
(2011/11/30)
-
- Sulfoxidation with hydrogen peroxide catalyzed by [SeO 4{WO(O2)2}2]2-
-
The selenium-containing dinuclear peroxotungstate, [(n-C4H 9)4N]2[SeO4{WO(O2) 2}2] (I), acts as a homogeneous catalyst for the selective oxidation of various kinds of cyclic mono- and disulfides with 30% aqueous H2O2. The cyclic disulfides were selectively oxidized to the corresponding monosulfoxides with one equivalent of H2O 2 with respect to the sulfides. In the presence of two equivalents of H2O2, the oxidation of dibenzothiophene gave the corresponding sulfone in 98% yield under the mild conditions. The negative Hammett ρ value (-0.62) for the competitive oxidation of p-substituted thioanisoles and the low XSO (XSO = (nucleophilic oxidation)/(total oxidation)) value of 0.14 for the I-catalyzed oxidation of thianthrene 5-oxide (SSO) revealed that I is a strong electrophilic oxidant. The reactivities of the di- and tetranuclear peroxotungstates with XO 4n- ligands (X = Se(vi), As(v), P(v), S(vi), and Si(iv)) were strongly dependent on the kinds of hetero atoms. The reaction rates for the sulfoxidation decreased with an increase in the XSO values and a peroxotungstate with a stronger electrophilicity was more active for the sulfoxidation. The kinetic and mechanistic investigations showed that the electrophilic attack of the peroxo oxygen at the sulfur atom is a key step in the sulfoxidation. The computational investigation supported the high chemoselectivitiy for the sulfoxidation of diallyl sulfide.
- Kamata, Keigo,Hirano, Tomohisa,Ishimoto, Ryo,Mizuno, Noritaka
-
supporting information; experimental part
p. 5509 - 5518
(2010/08/04)
-
- Simple and Friendly Sulfones Synthesis Using Aqueous Hydrogen Peroxide with a Reusable Keggin Molybdenum Heteropolyacid, Immobilized on Aminopropyl-Functionalized Silica
-
Keggin molybdenum heteropolyacid (H3PMo12O 40), immobilized on aminopropyl-functionalized silica catalysts, were made using two immobilization methods: incipient wetness and equilibrium adsorption. The material prepared for the equilibrium adsorption technique was found to be a highly efficient, ecofriendly, and recyclable heterogeneous catalyst for the selective oxidation of sulfides to sulfones in excellent yields, under mild reaction condition using 35% w/v aqueous hydrogen peroxide as the oxidant.
- Palermo, Valeria,Romanelli, Gustavo P.,Vazquez, Patricia G.
-
scheme or table
p. 3258 - 3268
(2010/04/26)
-
- Highly efficient oxidation of sulfides with hydrogen peroxide catalyzed by [SeO4{WO(O2)2}2]2-
-
By using the selenium-containing dinuclear peroxotungstate at 0.005-0.1 mol%, various kinds of sulfides could be converted into the corresponding sulfoxides or sulfones in excellent yields with one or two equivalents of H 2O2 with respect to the sulfide, respectively.
- Kamata, Keigo,Hirano, Tomohisa,Mizuno, Noritaka
-
supporting information; experimental part
p. 3958 - 3960
(2010/01/06)
-
- Selective and mild oxidation of sulfides to sulfoxides or sulfones using H2O2 and Cp′Mo(CO)3Cl as catalysts
-
Dialkyl, aryl-alkyl, benzylic, and benzothiophenic sulfides are selectively oxidized to sulfoxides or sulfones, with stoichiometric amounts of H2O2 (aq) or TBHP, in the presence of complexes Cp′Mo(CO)3Cl, CpMoO2Cl and the mesoporous material MCM-41-2 as catalysts. The use of the thianthrene 5-oxide (SSO) probe shows that CpMo(CO)3Cl/H2O2 or TBHP are electrophilic oxidants (Xso ≤ 15). The same conclusion is drawn from competition experiments with a mixture of p-ClC6H4SCH3 and C6H5SOCH3.
- Gamelas, Carla A.,Louren?o, Tiago,da Costa, André Pontes,Simplício, Ana L.,Royo, Beatriz,Rom?o, Carlos C.
-
p. 4708 - 4712
(2008/12/21)
-
- An economical and convenient synthesis of vinyl sulfones
-
A general process for the efficient synthesis of vinyl sulfones has been developed using commercially available sulfinic acid sodium salts and dibromides. A variety of phenyl and methyl vinyl sulfones have been formed in good yields, in the absence of any catalyst. Georg Thieme Verlag Stuttgart.
- Guan, Zheng-Hui,Zuo, Wei,Zhao, Lian-Biao,Ren, Zhi-Hui,Liang, Yong-Min
-
p. 1465 - 1470
(2008/02/05)
-
- L-proline-H2O2: A new chemoselective approach for oxidation of sulfides to sulfoxides
-
A facile and selective oxidation of sulfides to sulfoxides using an L-proline-H2O2 system for structurally divergent sulfide substrates with excellent yields at ambient conditions is reported. Copyright Taylor & Francis Group, LLC.
- Rajender Reddy,Rajasekhar,Ravindra
-
p. 3761 - 3766
(2007/10/03)
-
- Investigations on the iron-catalyzed asymmetric sulfide oxidation
-
The development of an enantioselective sulfide oxidation involving a chiral iron catalyst and aqueous hydrogen peroxide as oxidant is described. In the presence of a simple carboxylic acid, or a carboxylate salt, the reaction affords sulfoxides with remarkable enantioselectivities (up to 96% ee) in moderate to good yields. The influence of the structure of the additive on the reaction outcome is reported. In the sulfoxide-to-sulfone oxidation a kinetic resolution (with s = 4.8) occurs, which, however, plays only a negligible role in the overall enantioselective process. Furthermore, a positive nonlinear relationship between the ee of the product and that of the catalyst has been found. On the basis of these observations, a possible catalyst structure is proposed.
- Legros, Julien,Bolm, Carsten
-
p. 1086 - 1092
(2007/10/03)
-
- Facile method for solid-phase synthesis of vinyl sulfones using polystyrene-supported selenomethyl aryl sulfone
-
Treatment of novel polystyrene-supported selenomethyl aryl sulfone with LDA followed by alkylation and oxidation elimination efficiently afforded vinyl sulfones in good yields and purities.
- Sheng, Shou-Ri,Zhou, Wei,Zhong, Ming-Hua,Liu, Xiao-Ling,Chen, Hui-Zong
-
p. 815 - 821
(2007/10/03)
-
- Highly efficient utilization of H2O2 for oxygenation of organic sulfides catalyzed by [γ-SiW10O34(H 2O)2]4-
-
Remarkable efficiency of hydrogen peroxide utilization is reported for oxygenation of four organic sulfides catalyzed by a divacant lacunary silicotungstate, (Bu4N)4[γ-SiW10O 34(H2O)2] (1), under mild conditions. The addition of imidazole, phosphate, or carboxylates significantly enhances the rate of organic sulfide oxygenation. Most notably, use of 1 and imidazole, both at 1% molar concentration, resulted in the quantitative conversion of phenylsulfide to sulfoxide with 1 equiv of H2O2 in 3 h, and to sulfone with 2 equiv of H2O2 in 6 h.
- Phan, Tuan D.,Kinch, Mark A.,Barker, Julia E.,Ren, Tong
-
p. 397 - 400
(2007/10/03)
-
- Synthesis of Sulfoxides by the Hydrogen Peroxide Induced Oxidation of Sulfides Catalyzed by Iron Tetrakis(pentafluorophenyl)porphyrin: Scope and Chemoselectivity
-
The oxidation of sulfides with H2O2 catalyzed by iron tetrakis(pentafluorophenyl)porphyrin in EtOH is an efficient and chemoselective process. With a catalyst concentration 0.03-0.09% of that of the substrate, sulfoxides are obtained with yields generally around 90-95% of isolated product. With vinyl and allyl sulfides, no epoxidation is observed. With a catalyst concentration between 0.09% and 0.25% of that of the substrate, sulfones are obtained in almost quantitative yield and with the same high chemoselectivity observed in the synthesis of sulfoxides.
- Baciocchi, Enrico,Gerini, Maria Francesca,Lapi, Andrea
-
p. 3586 - 3589
(2007/10/03)
-
- Facile oxygenation of organic sulfides with H2O2 catalyzed by Mn-Me3TACN compounds
-
Two binuclear Mn-Me3TACN (Me3TACN is 1,4,7-N,N′,N″-trimethyl-1,4,7-triazacyclononane) compounds catalyze the oxygenation of organic sulfides utilizing H2O2 under ambient conditions. Both phenyl sulfide and ethyl phenyl sulfide were converted to the corresponding sulfones and chloroethyl phenyl sulfide proceeds to its elimination product of phenyl vinyl sulfone.
- Barker, Julia E.,Ren, Tong
-
p. 4681 - 4683
(2007/10/03)
-
- Chromium(VI) oxide catalyzed oxidation of sulfides to sulfones with periodic acid
-
A highly efficient and selective oxidation of sulfides to sulfones with periodic acid catalyzed by CrO3 is described. A variety of electron-rich and electron-deficient sulfides were oxidized to sulfones with 2 mol% CrO3 in acetonitrile at room temperature in excellent yields. Sulfides with other readily oxidized functional groups were selectively oxidized to sulfones in high yields with 10 mol% CrO3 in ethyl acetate/acetonitrile at -35 °C.
- Xu, Liang,Cheng, Jie,Trudell, Mark L.
-
p. 5388 - 5391
(2007/10/03)
-
- π-deficient 2-(arylsulfonyl)ethyl esters as protecting groups for carboxylic acids
-
Several π-deficient 2-(arylsulfonyl)ethyl groups have been studied as carboxylic acid protecting groups. The 2-[3,5-bis(trifluoromethyl)phenylsulfonyl]ethyl group is the most easily removed protecting group for acids under mild basic conditions using aqueous NaHCO3.
- Alonso, Diego A.,Nájera, Carmen,Varea, Montserrat
-
p. 277 - 287
(2007/10/03)
-
- Simple, economical and environmentally friendly sulfone synthesis
-
Chemoselective sulfur oxidation of functionalized sulfides was developed using catalytic amounts of MnSO4·H2O (1 mol%) and 30% H2O2 in the presence of a buffer solution of NaHCO3. Aromatic and aliphatic sulfides were oxidized to sulfones in quantitative yields in 15 min. Different functional groups including double bonds, alcohols, ethers of THP and TBDMS groups were tolerated under these mild and green reaction conditions.
- Alonso, Diego A.,Nájera, Carmen,Varea, Montserrat
-
p. 3459 - 3461
(2007/10/03)
-
- Tungstate-exchanged Mg-Al-LDH catalyst: An eco-compatible route for the oxidation of sulfides in aqueous medium
-
The catalytic oxidation of sulfides selectively to sulfoxides and/or sulfones is realised for the first time with heterogeneous tungstate-exchanged Mg-Al-LDH catalyst using 30% hydrogen peroxide in aqueous media at a faster rate in quantitative yields at room temperature. The heterogeneous catalyst showed higher activity (TOF) over its homogeneous analogues and other heterogeneous catalysts reported so far. The catalyst is well characterised by various instrumental techniques such as FT-IR spectroscopy, thermal analysis (TGA and DTA), powder XRD and chemical analysis. The catalyst is reused for six cycles with consistent activity and selectivity.
- Choudary,Bharathi,Venkat Reddy,Lakshmi Kantam
-
p. 2069 - 2074
(2007/10/03)
-
- Facile synthesis of vinyl sulfones from β-bromo alcohols
-
Vinyl sulfones are synthesized in good yields by dehydration of β- hydroxy sulfones derived from β-bromo alcohols.
- Lee, Jae Wook,Lee, Chi-Wan,Jung, Jin Hang,Oh, Dong Young
-
p. 2897 - 2902
(2007/10/03)
-