- Polymer-supported Oxobis(pentane-2,4-dionato)vanadium(IV) Catalyst for Reactions involving t-Butyl Hydroperoxide
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The polymer-supported title compound catalyses the homolytic decomposition of ButO2H and its reactions with Me2SO, Bun2S, and cyclohexene to give Me2SO2, Bun2SO, and cyclohexene oxide respectively.Polymer-chain participation in the radical reactions seems to give additional catalytic pathways for the decomposition of ButO2H.Recycling of the polymer-supported complex in the conversion of Me2SO into Me2SO2 results in lower product yields due to the loss of metal ions.Comparative studies between the polymer-supported and the homogeneous systems suggest extra stability for the polymer-anchored, catalytically active species.The diffusion barrier between the reactants in solution and the polymer influences the rates and may be responsible for this extra stability.
- Bhaduri, Sumit,Ghosh, Annoottam,Khwaja, Hanif
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- Switching the activity of a photoredox catalyst through reversible encapsulation and release
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Reversible encapsulation of [Ru(bpy)3]2+ within a self-assembled hexameric resorcin[4]arene capsule turns off the photocatalytic aerobic oxidation of an aliphatic sulfide. Upon addition of a competitive cationic guest, the Ru(ii) catalyst is released into solution where its catalytic activity is restored.
- Bianchini, Giulio,Scarso, Alessandro,Sorella, Giorgio La,Strukul, Giorgio
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- Nb and Zr modified MWW zeolites-characterisation and catalytic activity
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Hydrogen forms of MCM-22 and delaminated MCM-56 zeolites were modified with niobium and zirconium species. The structure/texture and surface properties, as well as the catalytic activity for dibutyl sulfide oxidation, of the two types of modified zeolites were compared. The presence of Br?nsted (BAS) and Lewis (LAS) acid sites was detected after pyridine adsorption in all the prepared materials. The highest number of BAS and LAS was observed for HMCM-22. The number of BAS significantly decreased after metal modification because of the interaction between the metal sources and the BAS. External silanol groups of zeolites also participate in metal anchoring. The catalysts obtained were tested for liquid phase dibutyl sulfide oxidation with hydrogen peroxide. The texture of the zeolites and the nature of the metal modifier have a crucial effect on the oxidation of dibutyl sulfide. MCM-56 zeolites are more active than their counterparts of MCM-22 type. Application of niobium containing zeolites significantly increases the reaction rate, leading to 95% conversion after 3 h. The remarkable role of the Nb species is due to its interaction with H2O2 towards peroxo/superoxo species. Modification of both zeolites with zirconium does not increase their activity because of the strong interaction of zirconium species with sulfur compounds. This journal is
- Wojtaszek-Gurdak, Anna,Ziolek, Maria
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- Reactions in clay media: Photooxidation of sulfides by clay-bound methylene blue
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Photooxidation of dialkyl and alkyl aryl sulfides to the corresponding sulfoxides with clay-bound methylene blue is studied in acetonitrile. A significant increase in sulfoxide/sulfone ratio and a marginal increase in cooxidation of a second sulfide molecule are observed. The results are explained in terms of a suitable mechanism involving persulfoxide and thiadioxirane intermediates.
- Madhavan,Pitchumani
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- Electron Transfer and Singlet Oxygen Mechanisms in the Photooxygenation of Dibutyl Sulfide and Thioanisole in MeCN Sensitized by N-Methylquinolinium Tetrafluoborate and 9,10-Dicyanoanthracene. The Probable Involvement of a Thiadioxirane Intermediate in Electron Transfer Photooxygenations
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Photooxygenations of PhSMe and Bu2S sensitized by N-methylquinolinium (NMQ+) and 9,10-dicyanoanthracene (DCA) in O 2-saturated MeCN have been investigated by laser and steady-state photolysis. Laser photolysis experiments showed that excited NMQ+ promotes the efficient formation of sulfide radical cations with both substrates either in the presence or in absence of a cosensitizer (toluene). In contrast, excited DCA promotes the formation of radical ions with PhSMe, but not with Bu2S. To observe radical ions with the latter substrate, the presence of a cosensitizer (biphenyl) was necessary. With Bu2S, only the dimeric form of the radical cation, (Bu2S)2 +., was observed, while the absorptions of both PhSMe+. and (PhSMe)2+. were present in the PhSMe time-resolved spectra. The decay of the radical cations followed second-order kinetics, which in the presence of O2, was attributed to the reaction of the radical cation (presumably in the monomeric form) with O2-. generated in the reaction between NMQ. or DCA-. and O 2. The fluorescence quenching of both NMQ+ and DCA was also investigated, and it was found that the fluorescence of the two sensitizers is efficiently quenched by both sulfides (rates controlled by diffusion) as well by O2 (kq = 5.9 × 109 M-1 s-1 with NMQ+ and 6.8 × 10 9 M-1 s-1 with DCA). It was also found that quenching of 1NMQ* by O2 led to the production of 1O2 in significant yield (φΔ = 0.86 in O 2-saturated solutions) as already observed for 1DCA* . The steady-state photolysis experiments showed that the NMQ+- and DCA-sensitized photooxygenation of PhSMe afford exclusively the corresponding sulfoxide. A different situation holds for Bu2S: with NMQ +, the formation of Bu2SO was accompanied by that of small amounts of Bu2S2; with DCA, the formation of Bu 2SO2 was also observed. It was conclusively shown that with both sensitizers, the photooxygenations of PhSMe occur by an electron transfer (ET) mechanism, as no sulfoxidation was observed in the presence of benzoquinone (BQ), which is a trap for O2-., NMQ ., and DCA-.. BQ also suppressed the NMQ +-sensitized photooxygenation of Bu2S, but not that sensitized by DCA, indicating that the former is an ET process, whereas the second proceeds via singlet oxygen. In agreement with the latter conclusion, it was also found that the relative rate of the DCA-induced photooxygenation of Bu2S decreases by increasing the initial concentration of the substrate and is slowed by DABCO (an efficient singlet oxygen quencher). To shed light on the actual role of a persulfoxide intermediate also in ET photooxygenations, experiments in the presence of Ph2SO (a trap for the persulfoxide) were carried out. Cooxidation of Ph2SO to form Ph2SO2 was, however, observed only in the DCA-induced photooxygenation of Bu2S, in line with the singlet oxygen mechanism suggested for this reaction. No detectable amounts of Ph2SO 2 were formed in the ET photooxygenations of PhSMe with both DCA and NMQ+ and of Bu2S with NMQ+. This finding, coupled with the observation that 1O2 and ET photooxygenations lead to different product distributions, makes it unlikely that, as currently believed, the two processes involve the same intermediate, i.e., a nucleophilic persulfoxide. Furthermore, the cooxidation of Ph 2SO observed in the DCA-induced photooxygenation of Bu2S was drastically reduced when the reaction was performed in the presence of 0.5 M biphenyl as a cosensitizer, that is, under conditions where an (indirect) ET mechanism should operate. This observation confirms that a persulfoxide is formed in singlet oxygen but not in ET photosulfoxidations. The latter conclusion was further supported by the observation that also the intermediate formed in the reaction of thianthrene radical cation with KO2, a reaction which mimics step d (Scheme 2) in the ET mechanism of photooxygenation, is an electrophilic species, being able to oxidize Ph2S but not Ph2SO. It is thus proposed that the intermediate involved in ET sulfoxidations is a thiadioxirane, whose properties (it is an electrophilic species) seem more in line with the observed chemistry. Theoretical calculations concerning the reaction of a sulfide radical cation with O 2-. provide a rationale for this proposal.
- Baciocchi, Enrico,Del Giacco, Tiziana,Elisei, Fausto,Gerini, Maria Francesca,Guerra, Maurizio,Lapi, Andrea,Liberali, Prisca
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- A Kinetic Study of Sulfide Oxidation by Sodium Hypochlorite Using Phase-Transfer Catalysis
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The use of sodium hypochlorite as a synthetically useful oxidizing agent is reported for the oxidation of lipophilic organic sulfide substrates employing phase-transfer catalysis (PTC).The PTC results in nearly complete oxidation of the substrate in 20 min, with high selectivity to the sulfoxide, compared to 5 h in its absence.Kinetic studies show the reaction occur via transfer of OCl- into the organic phase.Under certain conditions the transfer is rate limiting.The addition of a transition-metal catalyst (TPPMnCl) further increased the rate and led to the complete conversion of the sulfide to the sulfone, illustrating that NaOCl(aq) is a potent oxidizing agent in these biphasic systems.
- Ramsden, James H.,Drago, Russell S.,Riley, Richard
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- 4-Benzoylbenzoate intercalated in layered double hydroxides: A new catalyst for photo-oxidation of sulfides in solution and in the gas phase
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A new mixed organic-inorganic photosensitizer, based on 4-benzoylbenzoate intercalated into a layered double hydroxide has been prepared, characterized and successfully tested for the photo-oxidation of dialkylsulfides, both in acetonitrile and in the gas phase.
- Pigot, Thierry,Arbitre, Thomas,Martinez, Hervé,Lacombe, Sylvie
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- Polyoxometalate LUMO engineering: A strategy for visible-light-responsive aerobic oxygenation photocatalysts
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We report the efficient visible-light-responsive photocatalysis of polyoxometalates (POMs) by engineering the lowest unoccupied molecular orbitals (LUMOs). By the introduction of vanadium atoms into the γ-Keggin-type phosphotungstate, a new V3d/W5d mixed LUMO appeared to afford a visible-light-responsive catalyst (I), which showed high photocatalytic activity for aerobic oxygenation of sulfides to sulfoxides.
- Li, Chifeng,Suzuki, Kosuke,Mizuno, Noritaka,Yamaguchi, Kazuya
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- A mild and chemoselective CALB biocatalysed synthesis of sulfoxides exploiting the dual role of AcOEt as solvent and reagent
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A mild, chemoselective and sustainable biocatalysed synthesis of sulfoxides has been developed exploiting CALB and using AcOEt with a dual role of more environmentally friendly reaction solvent and enzyme substrate. A series of sulfoxides, including the drug omeprazole, have been synthesised in high yields and with excellent E-factors.
- Anselmi, Silvia,Liu, Siyu,Kim, Seong-Heun,Barry, Sarah M.,Moody, Thomas S.,Castagnolo, Daniele
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supporting information
p. 156 - 161
(2021/01/14)
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- Air atmospheric photocatalytic oxidation by ultrathin C,N-TiO2nanosheets
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Herein, we demonstrate the highly efficient photocatalytic sulfide oxidation reaction under mild conditions,i.e.in air, at room temperature and in the absence of a sacrificial reagent, co-catalyst or redox mediator, by using ultrathin C,N-TiO2nanosheets as a photocatalyst.
- Cheng, Xiuyan,Zhang, Jianling,Liu, Lifei,Zheng, Lirong,Zhang, Fanyu,Duan, Ran,Sha, Yufei,Su, Zhuizhui,Xie, Fei
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supporting information
p. 1165 - 1170
(2021/02/26)
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- Fe(III)-salen complex supported on dendrimer functionalized magnetite nanoparticles as a highly active and selective catalyst for the green oxidation of sulfides
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In this study, we reported the preparation of polyamidoamine-modified magnetite nanoparticles and their use for the immobilization of Fe(III)-salen complex to form a novel magnetic catalyst. The prepared catalyst was characterized by some modern techniques i.e. Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), N2 adsorption-desorption analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM), and inductively couple plasma atomic emission spectroscopy (ICP-AES). The catalyst showed excellent activity and selectivity for the oxidation of sulfides to sulfoxides (conversion 87–100percent, selectivity 82–100percent) using H2O2 (30percent w/w) as oxidant in aqueous medium at 50 °C. Furthermore, the catalyst could be recovered in a facile manner from the reaction mixture by using a magnet and reused for five cycles with high catalytic stability.
- Asadi, Zahra,Masteri-Farahani, Majid,Niakan, Mahsa
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- Selective catalytic oxidation of sulfides to sulfoxides or sulfones over amorphous Nb2O5/AC catalysts in aqueous phase at room temperature
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Selective oxidation of sulfides into sulfoxides or sulfones is an important transformation in organic synthesis. Activated carbon supported Nb-based catalysts were prepared by the impregnation method and then characterized by the XRD, TEM and XPS. The characterization results indicate Nb species is amorphous Nb2O5. The catalysts were applied for the catalytic oxidation of sulfides in aqueous phase with H2O2 as the oxidant. Sulfides could be converted into the corresponding sulfoxides or sulfones with high conversion and selectivity at room temperature. The recycling experiments showed the Nb2O5/AC catalysts exhibited good reusability. They could be recycled for 10 times without obvious loss of activity and selectivity.
- Zhang, Junjie,Jiang, Tingting,Mai, Yuliang,Wang, Xi,Chen, Jiazhi,Liao, Bing
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- An isotetramolybdate-supported rhenium carbonyl derivative: Synthesis, characterization, and use as a catalyst for sulfoxidation
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A novel isotetramolybdate-supported rhenium carbonyl derivative, [(CH3)4N]4[{Re(CO)3}4(Mo4O16)]·H2O (1), has been successfully synthesized and characterized by single crystal X-ray diffraction crystallography, IR and UV spectroscopy, etc. Results showed that, compound 1 is an efficient catalyst for the oxidation of thioanisole into the corresponding sulfoxide in the presence of hydrogen peroxide with good to excellent conversion (99%) and excellent selectivity (93%). Highly efficient oxygenation of thioanisole can also be achieved with 100% selectivity of sulfone and >99% conversion. Furthermore, optimized conditions were applied to a range of sulfides to obtain the corresponding sulfoxides and sulfones.
- Lu, Jingkun,Ma, Xinyi,Singh, Vikram,Zhang, Yujiao,Ma, Pengtao,Zhang, Chao,Niu, Jingyang,Wang, Jingping
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p. 5279 - 5285
(2018/04/23)
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- Catalytic Activity of Crystallographically Characterized Organic–Inorganic Hybrid Containing 1,5-Di-amino-pentane Tetrachloro Manganate with Perovskite Type Structure
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Abstract: Layered 2D organic–inorganic hybrid perovskite (OIHS) of the diammonium series, 1,5 di-aminepentane tetrachloro mangenate ([NH3–(CH2)5–NH3] MnCl4) was prepared by slow evaporation and reducing temperature method and characterized by single crystal X-ray diffraction analysis. Its structure consists of organic cation, [NH3(CH2)5NH3]+2 extended in a zigzag fashion and inorganic anion, [MnCl6]?2 where Mn2+ is coordinated by six Cl? ion in octahedral fashion. The organic and inorganic segments are alternately stacked along c-axis where inorganic layer is extended through corner-shared octahedra sandwiched by the di-aminopentane molecules. The layers (organic and inorganic) were connected to each other through N–HCl hydrogen bonds and van-der Waals interaction to build cation–anion–cation cohesion. The hybrid crystal had orthorhombic non-centrosymetric system having I212121 space group with unit cell parameters a = 7.1742(3) ?, b = 7.3817(3) ?, c = 23.9650(10) ?, V = 1269.13 ?3 and Z = 4. The hybrid exhibited excellent catalytic activity towards sulphide and alkene oxidation using aqueous H2O2 as an oxidant. Graphical Abstract: OIHS of the diammonium series [NH3–(CH2)5–NH3] MnCl4; 1,5 di-aminepentane tetrachloro mangenate were prepared by slow evaporation and temperature decrease method, characterized by single crystal X-ray diffraction. This complex exhibits excellent catalytic activity towards sulphide oxidation and alkene oxidation using aqueous H2O2 as an oxidant. [Figure not available: see fulltext.].
- Mondal, Paramita,Abdel-Aal, Seham Kamal,Das, Debasis,Islam, Sk Manirul
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p. 2332 - 2339
(2017/08/22)
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- The Polyoxovanadate-Based Carboxylate Derivative K6H[VV17VIV12(OH)4O60(OOC(CH2)4COO)8]·nH2O: Synthesis, Crystal Structure, and Catalysis for Oxidation of Sulfides
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The high-nuclearity polyoxovanadate-based carboxylate derivative K6H[VV17VIV12(OH)4O60(OOC(CH2)4COO)8]·nH2O (1) has been successfully synthesized by conventional aqueous methods and structurally characterized. The [VV17VIV12(OH)4O60(OOC(CH2)4COO)8]7- polyanion is built up from three cages: one {VV17(OH)4O44} cage and two identical [(VIV3O6)2(OOC(CH2)4COO)4]8- cages. Of the three cages, the {VV17(OH)4O44} is a purely inorganic polyoxovanadate cluster, whereas each of the [(VIV3O6)2(OOC(CH2)4COO)4]8- cages is a vanadium-based organic-inorganic hybrid cluster framed via four adipate ligands linking simultaneously to two triangular {V3} units. The two [(VIV3O6)2(OOC(CH2)4COO)4]8- cages are covalently attached to the central {VV17(OH)4O44} cage via V-O-V bonds in a linear arrangement, resulting in a {V29}-based hybrid cluster skeleton. The catalytic properties of compound 1 for the oxidation of sulfides by tert-butyl hydroperoxide were investigated, and the result indicates that 1 exhibits excellent catalytic activity for the oxidation of sulfides under mild conditions.
- Wang, Ke,Niu, Yanjun,Zhao, Dongyan,Zhao, Yanxin,Ma, Pengtao,Zhang, Dongdi,Wang, Jingping,Niu, Jingyang
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p. 14053 - 14059
(2017/11/27)
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- Epoxidation of alkenes and oxidation of sulfides catalyzed by a new binuclear vanadium bis-oxazoline complex
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Bis(oxazoline) ligand, [2,2′-(1,3-phenylene)bis(oxazole-4,2-diyl)]-dimethanol, derived from dicyanobenzene was applied as ligand for complexation with vanadium.The catalyst was characterized by FT-IR, UV-Vis, 1H NMR spectroscopic methods, CHNS, ICP and thermal analyses, and magnetic susceptibility. The catalytic activity of this complex was then studied in the epoxidation of alkenes with TBHP (tert-butyl hydroperoxide), in acetonitrile. The effect of reaction parameters such as kind of solvent and oxygen donors was studied in the epoxidation of cyclooctene. The catalytic activity of this catalyst was also investigated in the oxidation of sulfides with H2O2 in ethanol and the corresponding sulfoxides and sulfones were produced.
- Javadi, Maedeh Moshref,Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah
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p. 477 - 485
(2015/02/05)
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- Effect of irradiation intensity on rate and selectivity of photosensitized oxidation of dibutyl sulfide over C70 fullerene
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Photoinitiated oxidation of dibutyl sulfide (DBS) with air oxygen in a toluene solution of C70 fullerene during irradiation with visible light at a wavelength of 500-700 nm results in the formation of dibutyl sulfone as a main detected product, dibutyl sulfoxide, and butanal. A change in the intensity of radiation incident on the reaction mixture from 2.2 to 44 mW/cm2 insignificantly increases the quantum efficiency of the DBS consumption from 4.5 to 5.9%. The selectivity for sulfoxide increases during the process, while selectivity for sulfone decreases.
- Arsentyev,Vorontsov,Parmon
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p. 167 - 172
(2015/05/20)
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- Selective hydrogen peroxide oxidation of sulfides to sulfoxides or sulfones with MWW-type titanosilicate zeolite catalyst under organic solvent-free conditions
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Selective oxidation of sulfides to sulfoxides and sulfones with hydrogen peroxide under organic solvent-free conditions was demonstrated by the MWW-type titanosilicate zeolite catalyst. Sulfides were oxidized smoothly to give sulfoxides with good selectivities at ambient temperature using 1.0-1.2 equiv of hydrogen peroxide with the MWW-type titanosilicate zeolite catalyst. Especially, the Ti-MWW with an interlayer-expanded structure (Ti-IEZ-MWW) catalyst showed high activity with good chemoselectivity for the oxidation of various sulfides. The catalyst is recyclable for at least five cycles, and the only byproduct is water. Sulfides were directly oxidized to give sulfones in high yields by 2.5 equiv of hydrogen peroxide with the MWW-type titanosilicate zeolite catalyst under organic solvent-free conditions.
- Kon, Yoshihiro,Yokoi, Toshiyuki,Yoshioka, Masato,Tanaka, Shinji,Uesaka, Yumiko,Mochizuki, Takehisa,Sato, Kazuhiko,Tatsumi, Takashi
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p. 7584 - 7592
(2014/12/10)
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- Highly efficient selective oxidation of sulfides to sulfoxides by montmorillonite-immobilized metalloporphyrins in the presence of molecular oxygen
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Highly efficient and selective oxidation of sulfides to sulfoxides with dioxygen catalyzed by cationic meso-tetrakis (1-methyl-4-pyridyl) (TM4PyP) metalloporphyrins immobilized into montmorillonite (MT) interlayer was achieved. Manganese (II) porphyrin (MnTM4PyP-MT) presented excellent activity for the oxidation of sulfides under ambient conditions. In the model oxidation, thioanisole was converted completely and the selectivity towards sulfoxide was up to 95%. This catalyst also showed high activity and selectivity for the most sulfides. The catalyst could be reused consecutively five times without significant loss of activity.
- Zhou, Xian-Tai,Ji, Hong-Bing
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- Acidic three-liquid-phase microemulsion systems based on balanced catalytic surfactant for epoxidation and sulfide oxidation under mild conditions
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Didecyldimethylammonium tungstate has been designed as a balanced catalytic surfactant to form acidic three-liquid-phase microemulsion systems at room temperature in the presence of water, a non-chlorinated solvent and dimethyldioctylammonium salts (hydrogen sulfate and dihydrogen phosphate). The triphasic system is efficient for the oxidation of olefins, sulfides and thiophenes under mild conditions. Moreover, the recovery and reusability of the catalyst, the straightforward separation of products and catalysts in two distinct phases as well as the possible use of environmentally friendly solvents such as tert-butyl acetate, make this system particularly attractive for catalytic oxidation reactions involving hydrogen peroxide as the primary oxidant under acidic or neutral conditions.
- Fressancourt-Collinet, Marion,Hong, Bing,Leclercq, Loic,Alsters, Paul L.,Aubry, Jean-Marie,Nardello-Rataj, Veronique
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supporting information
p. 409 - 420
(2013/05/22)
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- Selective oxidation of bulky sulfides to sulfoxides over titanosilicates having an MWW structure in the presence of H2O2 under organic solvent-free conditions
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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
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supporting information
p. 4918 - 4921
(2013/09/02)
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- Versatile eco-friendly pickering emulsions based on substrate/native cyclodextrin complexes: A winning approach for solvent-free oxidations
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Solvent-less Pickering emulsions were developed and applied to catalytic oxidation. These systems are stabilized by inclusion complexes between cyclodextrins and substrates, forming a 3D network among the dispersed phase. In the presence of hydrogen peroxide as a green oxidant and [Na] 3[PW12O40] as a catalyst, they provide particularly efficient reaction media for the oxidation of olefins, organosulfurs, and alcohols. The reactions proceed at competitive rates (up to 400 h-1) with straightforward separation of the phases by centrifugation or heating. Moreover, these new eco-friendly systems work at a preparative scale (up to 2.5 M) and are recycled without loss of activity. Disperse and conquer! Solvent-less Pickering emulsions have been developed and applied to catalytic oxidation. The systems are stabilized by inclusion complexes between cyclodextrins and substrates forming a 3D network among the dispersed phase. In the presence of hydrogen peroxide as a green oxidant and [Na]3[PW12O40] as a catalyst, they provide particularly efficient eco-friendly reaction media for the oxidation of olefins, organosulfurs, and alcohols. Copyright
- Leclercq, Lo?c,Company, Roberto,Mühlbauer, Andrea,Mouret, Adrien,Aubry, Jean-Marie,Nardello-Rataj, Véronique
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p. 1533 - 1540
(2013/09/12)
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- Synthesis, crystal structure and spectroscopic studies of a cobalt(III) Schiff base complex and its use as a heterogeneous catalyst for the oxidation reaction under mild condition
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A new Schiff base oriented Co(III) complex, (CoL)Cl4H2O (L = Schiff base), has been synthesized by careful design of the Schiff base ligand thorough oxidation of Co(II) to Co(III) during the reaction process. The complex has been characterized by single-crystal X-ray structure analysis and various spectral analyses. Structure analysis reveals that this monomeric complex crystallizes in triclinic P-1 space group. Supramolecular hydrogen bonding interactions among the guest water molecules and counter anion chloride leads to the formation of 1D water-chloride chain. A polymer anchored heterogeneous cobalt complex has been synthesized, characterized by various physicochemical techniques and successfully used for the oxidation of alkenes and sulfides using H2O2 as oxygen source. The influence of the various reaction parameters has been studied. The heterogeneous cobalt complex can be reused seven times without any significant loss in its catalytic activity.
- Islam, S. Manirul,Roy, Anupam Singha,Dalapati, Sasanka,Saha, Rajat,Mondal, Paramita,Ghosh, Kajari,Chatterjee, Saptarshi,Sarkar, Keka,Guchhait, Nikhil,Mitra, Partho
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- Evidence of two key intermediates contributing to the selectivity of P450-biomimetic oxidation of sulfides to sulfoxides and sulfones
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A mild process for the selective oxidation of sulfides is in great demand. Therefore, probing the mechanism underlying the biological oxidation of sulfides under ambient conditions may provide valuable insights for the development of such a reaction. Based on porphyrin models of P450 enzymes, evidence of two key intermediates, Int0 and Int1, in this reaction is provided. Spectroscopic studies indicated the formation of a hydroperoxide-iron(III) species (Int0) upon addition of H2O2. This intermediate proved to be highly selective for sulfoxide production. By contrast, a defined porphyrin oxoiron(IV) cation radical (Int1) directly reacted with sulfoxides, leading selectively to the corresponding sulfones. Interestingly, the available sulfoxides reversibly act as a new axial ligand for Int0 forming a more active species Int0 SO. The amount of Int0 increased in the presence of alkyl, aryl, or aromatic sulfides, while Int1 formed in the absence of these sulfides. Thus, sulfoxides and sulfones would selectively form under conditions that favor the corresponding intermediates, which elucidate the biological oxidation pathway. A mild process for the selective oxidation of sulfides is in great demand. Therefore, probing the mechanism underlying the biological oxidation of sulfides under ambient conditions may provide valuable insights for the development of such a reaction. Based on porphyrin models of P450 enzymes, evidence of two key intermediates, Int0 and Int1, in this reaction is provided. Copyright
- Zhou, Xinrui,Chen, Xian,Jin, Yaqin,Marko, Istvan E.
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p. 2253 - 2257,5
(2020/08/24)
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- Synthesis, catalytic oxidation and oxidative bromination reaction of a reusable polymer anchored oxovanadium(IV) complex
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Polymer anchored oxovanadium catalyst was synthesized and characterized. The solid catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). Its catalytic activity was evaluated for the oxidation of various alkenes, sulfides and aromatic alcohols with 30% H2O2 under mild reaction conditions. This catalyst was also effective for the oxidative bromination reaction of organic substrates with 80-100% selectivity of mono substituted products with H2O2/KBr at room temperature. The above reactions require minimum amount of H2O2, short time period and most importantly all the above reactions occur in aqueous medium. The developed catalyst can be facilely recovered and reused six times without significant decrease in activity and selectivity. This result confirms that the polymer anchored complex was not leached during the reaction, suggesting the true heterogeneous nature of the catalyst.
- Islam, Sk. Manirul,Roy, Anupam Singha,Mondal, Paramita,Salam, Noor
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experimental part
p. 38 - 48
(2012/05/21)
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- A manganese(V)-oxo π-cation radical complex: Influence of one-electron oxidation on oxygen-atom transfer
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One-electron oxidation of MnV-oxo corrolazine 2 affords 2 +, the first example of a MnV(O) π-cation radical porphyrinoid complex, which was characterized by UV-vis, EPR, LDI-MS, and DFT methods. Access to 2 and 2+ allowed for a direct comparison of their reactivities in oxygen-atom transfer (OAT) reactions. Both complexes are capable of OAT to PPh3 and RSR substrates, and 2+ was found to be a more potent oxidant than 2. Analysis of rate constants and activation parameters, together with DFT calculations, points to a concerted OAT mechanism for 2+ and 2 and indicates that the greater electrophilicity of 2+ likely plays a dominant role in enhancing its reactivity. These results are relevant to comparisons between Compound I and Compound II in heme enzymes.
- Prokop, Katharine A.,Neu, Heather M.,De Visser, Sam P.,Goldberg, David P.
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scheme or table
p. 15874 - 15877
(2011/11/13)
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- CARBOCATALYSTS FOR CHEMICAL TRANSFORMATIONS
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The disclosure relates to catalytically active carbocatalysts, e.g., a graphene oxide or graphite oxide catalyst suitable for use in a variety of chemical transformations. In one embodiment, it relates to a method of catalyzing a chemical reaction of an organic molecule by reacting the organic molecule in the presence of a sufficient amount of graphene oxide or graphite oxide for a time and at a temperature sufficient to allow catalysis of a chemical reaction. According to other embodiments, the reaction may be an oxidation reaction, a hydration reaction, a dehydrogenation reaction, a condensation reaction, or a polymerization reaction. Some reactions may include auto-tandem reactions. The disclosure further provides reaction mixtures containing an organic molecule and graphene oxide or graphite oxide in an amount sufficient to catalyze a reaction of the organic molecule.
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Page/Page column 58-59
(2011/12/14)
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- Ti(iv)-amino triphenolate complexes as effective catalysts for sulfoxidation
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C 3-symmetric Ti (iv) amino triphenolate complexes efficiently catalyze, without previous activation and in excellent yields, the oxidation of sulfides at room temperature, using both CHP and the more environment friendly aqueous hydrogen peroxide as terminal oxidants, with catalyst loadings down to 0.01%. The Ti(iv) catalysts and the intermediate Ti(iv)-peroxo complexes have been characterized in solution by 1H NMR and ESI-MS techniques and via density functional studies.
- Mba, Miriam,Prins, Leonard J.,Zonta, Cristiano,Cametti, Massimo,Valkonen, Arto,Rissanen, Kari,Licini, Giulia
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experimental part
p. 7384 - 7392
(2010/09/17)
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- Controlled oxidation of organic sulfides to sulfoxides under ambient conditions by a series of titanium isopropoxide complexes using environmentally benign H2O2 as an oxidant
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Controlled oxidation of organic sulfides to sulfoxides under ambient conditions has been achieved by a series of titanium isopropoxide complexes that use environmentally benign H2O2 as a primary oxidant. Specifically, the [N,N′-bis(2-oxo-3-R1-5-R2- phenylmethyl)-N,N′-bis(methylene-R3)-ethylenediamine]Ti(O iPr)2 [R1 = t-Bu, R2 = Me, R 3 = C7H5O2 (1b); R1 = R2 = t-Bu, R3 = C7H5O2 (2b); R1 = R2 = Cl, R3 = C7H 5O2 (3b) and R1 = R2 = Cl, R 3 = C6H5 (4b)] complexes efficiently catalyzed the sulfoxidation reactions of organic sulfides to sulfoxides at room temperature within 30 min of the reaction time using aqueous H2O 2 as an oxidant. A mechanistic pathway, modeled using density functional theory for a representative thioanisole substrate catalyzed by 4b, suggested that the reaction proceeds via a titanium peroxo intermediate 4c′, which displays an activation barrier of 22.5 kcal mol-1 (ΔG?) for the overall catalytic cycle in undergoing an attack by the S atom of the thioanisole substrate at its σ*-orbital of the peroxo moiety. The formation of the titanium peroxo intermediate was experimentally corroborated by a mild ionization atmospheric pressure chemical ionization (APCI) mass spectrometric technique. The Royal Society of Chemistry 2010.
- Panda, Manas K.,Shaikh, Mobin M.,Ghosh, Prasenjit
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experimental part
p. 2428 - 2440
(2010/06/18)
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- Oxidation of sulfides with a silica-supported peracid in supercritical carbon dioxide under flow conditions: Tuning chemoselectivity with pressure
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Supercritical carbon dioxide is a convenient medium for performing the selective oxidation of sulfides 1 to either sulfoxides 2 or sulfones 3 with [2-percarboxyethyl]-functionalized silica (4) under flow conditions. The chemoselectivity of the reaction, which results from the different diffusion rates of sulfide and sulfoxide over the reagent bed, can be controlled by adjusting the pressure and the hydration of the silica surface as both the solvating power of the mobile phase and the surface activity of the stationary phase determine the migration rates of sulfide 1 and sulfoxide 2 over the supported peroxide. The results elucidate the impact of surface phenomena on the course of chemical reactions carried out under flow conditions. The oxidation of sulfides 1 with hydrated [2-percarboxyethyl]-functionalized silica (4) in scCO2 under flow conditions can be tuned to give either sulfoxides 2 or sulfones 3 by adjusting the pressure.
- Mello, Rossella,Olmos, Andrea,Alcalde-Aragones, Ana,Diaz-Rodriguez, Alba,Gonzalez Nunez, Maria Elena,Asensio, Gregorio
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supporting information; experimental part
p. 6200 - 6206
(2011/01/05)
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- Observed and calculated 1Hand 13C chemical shifts induced by the in situ oxidation ofmodel sulfides to sulfoxides and sulfones
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A series of model sulfides was oxidized in the NMR sample tube to sulfoxides and sulfones by the stepwise addition of meta-chloroperbenzoic acid in deuterochloroform. Various methods of quantum chemical calculations have been tested to reproduce the observed 1H and 13C chemical shifts of the starting sulfides and their oxidation products. It has been shown that the determination of the energy-minimized conformation is a very important condition for obtaining realistic data in the subsequent calculation of the NMR chemical shifts. The correlation between calculated and observed chemical shifts is very good for carbon atoms (even for the 'cheap' DFT B3LYP/6-31G* method) and somewhat less satisfactory for hydrogen atoms. The calculated chemical shifts induced by oxidation (the δd values) agree even better with the experimental values and can also be used to determine the oxidation state of the sulfur atom (-S-, -SO-, -SO2 -). Copyright
- Dracinsky, Martin,Pohl, Radek,Slavetinska, Lenka,Budesinsky, Milos
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experimental part
p. 718 - 726
(2011/05/15)
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- A flexible nonporous heterogeneous catalyst for size-selective oxidation through a bottom-up approach
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Size does matter: The nonporous tetra-n-butylammonium salt of silicodecatungstate, synthesized through a bottom-up approach, heterogeneously catalyzes the size-selective oxidation of various organic compounds, including olefins, sulfides, and organosilanes, with aqueous H2O2 in ethyl acetate. The catalyst can be easily separated by filtration and reused several times with retention of high catalytic activity. Copyright
- Mizuno, Noritaka,Uchida, Sayaka,Kamata, Keigo,Ishimoto, Ryo,Nojima, Susumu,Yonehara, Koji,Sumida, Yasutaka
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supporting information; experimental part
p. 9972 - 9976
(2011/03/18)
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- Thermodynamics of halogen bonding in solution: Substituent, structural, and solvent effects
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A detailed study of the thermodynamics of the halogen-bonding interaction in organic solution is presented. 19F NMR titrations are used to determine association constants for the interactions of a variety of Lewis bases with fluorinated iodoalkanes and iodoarenes. Linear free energy relationships for the halogen bond donor ability of substituted iodoperfluoroarenes XC 6F4I are described, demonstrating that both substituent constants (σ) and calculated molecular electrostatic potential surfaces are useful for constructing such relationships. An electrostatic model is, however, limited in its ability to provide correlation with a more comprehensive data set in which both halogen bond donor and acceptor abilities are varied: the ability of computationally derived binding energies to accurately model such data is elucidated. Solvent effects also reveal limitations of a purely electrostatic depiction of halogen bonding and point to important differences between halogen bonding and hydrogen bonding.
- Sarwar, Mohammed G.,Dragisic, Bojan,Salsberg, Lee J.,Gouliaras, Christina,Taylor, Mark S.
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supporting information; scheme or table
p. 1646 - 1653
(2010/04/04)
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- Chemoselective sulfoxidation by H2O2 or HNO3 using a phosphate impregnated titania catalyst
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A variety of organosulfur compounds have been selectively oxidized to the corresponding sulfoxides by either H2O2 or HNO3 using a newly developed solid acid catalyst composed of 84.5% of TiO2 and 15.5% of [Ti4H11(PO4)9]·nH2O (n = 1-4). The chemoselective oxidation of sulfides in the presence of vulnerable groups such as -CN, -C{double bond, long}C-, -CHO, or -OH, as well as sulfoxidation of substrates like benzothiazole, glycosyl sulfide, and dibenzothiophenes is some of the important attribute of the protocol. Nitric acid, under the present experimental conditions, brings about relatively better selectivity than hydrogen peroxide.
- Bharadwaj, Saitanya K.,Sharma, Susanda N.,Hussain, Sahid,Chaudhuri, Mihir K.
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experimental part
p. 3767 - 3771
(2009/10/11)
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- Highly selective 30% hydrogen peroxide oxidation of sulfides to sulfoxides using micromixing
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The highly selective oxidation of sulfides to sulfoxides using 30% hydrogen peroxide has been achieved under catalyst-free conditions using a T-shaped micromixer. The Royal Society of Chemistry.
- Noguchi, Takuya,Hirai, Yoshiro,Kirihara, Masayuki
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scheme or table
p. 3040 - 3042
(2009/02/04)
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- C3-symmetric Ti(IV) triphenolate amino complexes as sulfoxidation catalysts with aqueous hydrogen peroxide
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(Chemical Equation Presented) The Ti(IV) complex 2c bearing a C 3-symmetric triphenolate amine ligand is an air and moisture tolerant complex that efficiently catalyzes sulfoxidation reactions at room temperature without previous activation (catalyst loading down to 0.01%, TONs up to 8000, TOFs up to 1700 h-1, quantitative yields). Reactions were performed with aqueous hydrogen peroxide as oxidant, which adds value to the methodology from the environmental viewpoint.
- Mba, Myriam,Prins, Leonard J.,Licini, Giulia
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- Micelle directed synthesis of polyoxometalate nanoparticles and their improved catalytic activity for the aerobic oxidation of sulfides
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Micelle directed polyoxometalate nanoparticles were synthesized by depositing H3+xPVxMo12-xO40 (x = 0, 2) by precipitation on micelles prepared from cesium dodecyl sulfate. The cryo-TEM image showed particles of about ～10 nm roughly consistent with the particle size computed from an idealized model. HRTEM coupled with EELS imaging to map the distribution of the elements also supported the formation of micelle directed polyoxometalate nanoparticles. In the aerobic oxidation of various sulfides to sulfoxides and sulfones, the clustered polyoxometalate assemblies supported on hydrophilic silica showed significantly higher catalytic activity versus that of nonclustered assemblies. Copyright
- Maayan, Galia,Popovitz-Biro, Ronit,Neumann, Ronny
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p. 4968 - 4969
(2007/10/03)
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- WO3 Nanoparticles on MCM-48 as a Highly Selective and Versatile Heterogeneous Catalyst for the Oxidation of Olefins, Sulfides, and Cyclic Ketones
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It is shown that nanosized WO3 particles supported on MCM-48 work as a highly efficient and selective heterogeneous catalyst for the oxidation of olefins, sulfides, and cyclic ketones using hydrogen peroxide or peracetic acid. The catalytic activity of the supported tungstate was dependent on the nature of the supporting materials and particle size. The catalyst system employs environmentally benign oxidants in halide-free solvents, and it does not require phase-transfer agents and pH control.
- Koo, Dong Hyun,Kim, Min,Chang, Sukbok
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p. 5015 - 5018
(2007/10/03)
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- Selective oxidation of sulfides to sulfoxides and sulfones using n-butyltriphenylphosphonium dichromate (BunPPh3) 2Cr2O7 in the presence of aluminium chloride in solution and under microwave irradiation
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A wide variety of sulfides are efficiently oxidized to their corresponding sulfoxides and sulfones in excellent yields using n-butyltriphenylphosphonium dichromate (BTPPDC) in the presence of aluminium chloride in acetonitrile solution and under microwave irradiation. In addition, selective oxidation of sulfides in the presence of functional groups such as a carbon-carbon double bond, ketone, oxime, aldehyde, ether, and acetal can be considered as a noteworthy advantage of this method. Copyright Taylor & Francis Inc.
- Mohammadpoor-Baltork, Iraj,Memarian, Hamid Reza,Bahrami, Kiumars,Esmayilpour, Karim
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p. 2751 - 2766
(2007/10/03)
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- 3-Carboxypyridinium chlorochromate - aluminium chloride - An efficient and inexpensive reagent system for the selective oxidation of sulfides to sulfoxides and sulfones in solution and under microwave irradiation
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3-Carboxypyridinium chlorochromate (CPCC) in the presence of aluminium chloride is a very efficient reagent for the selective oxidation of sulfides to sulfoxide and sulfones in solution and under microwave irradiation. It is noteworthy that different functional groups including carbon-carbon double bonds, ketones, oximes, aldehydes, ethers, and acetals were tolerated under these reaction conditions.
- Mohammadpoor-Baltork, Iraj,Memarian, Hamid R.,Bahrami, Kiumars
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p. 115 - 121
(2007/10/03)
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- Liquid-phase oxidation of sulfides by an aluminum (and titanium) tert-butoxide - tert-butyl hydroperoxide system
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A system aluminum (and titanium) tert-butoxide-tert-butyl hydroperoxide (1 : 2) under mild conditions (20°C, 1 h) oxidizes aliphatic and alkylaromatic sulfides and diphenyl sulfide to the corresponding sulfones in yields close to ～100%. The oxidation is induced by electron-excited dioxygen formed upon thermal decomposition of intermediate metal-containing peroxy trioxides (ozonides). The latter are formed as a result of the reversible reaction of aluminum or titanium tert-butoxides with tert-butyl hydroperoxide followed by the interaction of di-tert-butoxy-tert-butylperoxyaluminum and tri-tert-butoxy-tert-butylperoxytitanium that formed with another Bu tOOH molecule. Alkminum-containing peroxide (ButO) 2AlOOBut oxidizes sulfides to sulfoxides.
- Dodonov,Zaburdaeva,Stepovik
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p. 1729 - 1734
(2007/10/03)
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- Cerium(III) bromate as a new reagent in oxidation of organic compounds
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Cerium(III) bromate, prepared by the reaction of barium bromate with cerium(III) sulfate, can be used for the oxidation of alkylarenes, alcohols, and sulfides. Products are obtained in high yields under mild conditions. Ce(BrO3)3 is an unique, dual property reagent in which the anion is the oxidant and the cation a catalyst. Stoichiometric studies indicate that bromate is reduced to bromide under these conditions, making the process highly efficient.
- Shaabani, Ahmad,Lee, Donald G.
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p. 1845 - 1854
(2007/10/03)
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- Mechanisms of hydrogen-, oxygen-, and electron-transfer reactions of cumylperoxyl radical
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Rates of hydrogen-transfer reactions from a series of para-substituted N,N-dimethylanilines to cumylperoxyl radical and oxygen-transfer reactions from cumylperoxyl radical to a series of sulfides and phosphines have been determined in propionitrile (EtCN) and pentane at low temperatures by use of ESR. The observed rate constants exhibit first-order and second-order dependence with respect to concentrations of N,N-dimethylanilines. This indicates that the hydrogen- and oxygen-transfer reactions proceed via 1:1 charge-transfer (CT) complexes formed between the substrates and cumylperoxyl radical. The primary kinetic isotope effects are determined by comparing the rates of N,N-dimethylanilines and the corresponding N,N-bis(trideuteriomethyl)anilines. The isotope effect profiles are quite different from those reported for the P-450 model oxidation of the same series of substrates. Rates of electron-transfer reactions from ferrocene derivatives to cumylperoxyl radical have also been determined by use of ESR. The catalytic effects of Sc(OTf)3 (OTf = triflate) on the electron-transfer reactions are compared with those of Sc(OTf)3 on the hydrogen- and oxygen-transfer reactions. Such comparison provides strong evidence that the hydrogen- and oxygen- transfer reactions of cumylperoxyl radical proceed via a one-step hydrogen atom and oxygen atom transfer rather than via an electron transfer from substrates to cumylperoxyl radical.
- Fukuzumi, Shunichi,Shimoosako, Kanji,Suenobu, Tomoyoshi,Watanabe, Yoshihito
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p. 9074 - 9082
(2007/10/03)
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- Destruction of toxic organophosphorus and organosulfur pollutants by perpropionic acid: The first stable, industrial liquid water-miscible peroxyacid in decontamination
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Use of commercial perpropionic acid (PPA), the first stable, industrial and water-miscible peroxyacid, allows the destruction of toxic organophosphorus and organosulfur compounds under micellar conditions. The destruction of paraoxon (O,O-diethyl O-p-nitrophenylphosphate), di-n-butyl sulfide and 2-chloro-2′-phenyldiethyl sulfide has been studied.
- Lion, Claude,Da Conceicao, Louis,Hecquet, Gerard,Pralus, Christian,Requieme, Benoit,Schirmann, Jean-Pierre
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p. 1515 - 1518
(2007/10/03)
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- Polyethylene glycol as a non-ionic liquid solvent for polyoxometalate catalyzed aerobic oxidation
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The H5PV2Mo10O40 polyoxometalate in a polyethylene glycol solvent was effective for a series of aerobic oxidation reactions including oxydehydrogenation of alcohols and cyclic dienes, oxidation of sulfides and the Wacker reaction; the solvent-catalyst phase can be recovered and recycled.
- Haimov, Adina,Neumann, Ronny
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p. 876 - 877
(2007/10/03)
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- New ω-phthalimidoperoxyalkanoic acids in decontamination. Destruction of some toxic organophosphorus and organosulfur pollutants
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Chemical decontamination of toxic compounds (chemical warfare agents and/or insecticides) is of increasing importance. In this study, we report the use of ω-phthalimidoperoxyalkanoic acids 2 in the destruction of paraoxon (O,O-diethyl-O-para-nitrophenylphosphate), a well-known insecticide, and 2-chloro-2′-phenyldiethyl sulfide (a half mustard). We show that while all the peroxyacids used in this series allow the destruction of toxic compounds, the length n of the alkanoic side chain is important to the choice of the optimal industrial compound, which is 2d (n = 5).
- Lion,Da Conceicao,Delmas,Magnaud
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p. 1182 - 1184
(2007/10/03)
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- Surface-mediated reactions. 8. Oxidation of sulfides and sulfoxides with tert-butyl hydroperoxide and OXONE
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Silica gel and alumina have been found to mediate the oxidation of sulfides and sulfoxides with (CH3)3COOH and OXONE. With all combinations except (CH3)3COOH/alumina, sulfides were oxidized with reasonably good selectivity to sulfoxides. These studies afforded insights into the mechanisms of surface-mediated processes. Adsorption studies, combined with the effect of partial silylation of silica gel, indicate that oxidation of sulfides by (CH3)3COOH/silica gel occurs at least predominantly via nucleophilic attack by the sulfide on (CH3)3COOH, which is activated by being bound to isolated silanol sites on the silica gel surface (Scheme 2), whereas oxidation of sulfoxides involves nucleophilic attack by (CH3)3COOH on the sulfoxide, which is activated by being bound to associated silanol sites (Scheme 3). Oxidation of sulfoxides by (CH3)3COOH/alumina involves attack of (CH3)3COO- on the sulfoxide bound to free Al+ sites on the surface (Scheme 4B). Mediation of oxidation by OXONE involves instead activation by its being dispersed on the surface of the adsorbent, providing contact between KOSO2OOH, the oxidizing component, and the substrate. With silica gel, binding involves the associated silanol sites (Scheme 5). It is proposed that this is a general model for surface mediation of inorganic salts.
- Kropp, Paul J.,Breton, Gary W.,Fields, John D.,Tung, Jesse C.,Loomis, Brian R.
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p. 4280 - 4285
(2007/10/03)
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- -
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New initiators 1-7, analogues of tetra-acetylethylenediamine, have been prepared and their use in the in situ generation of peroxyacids by reaction with sodium peroxycarbonate described. The kinetics of perhydrolysis of these initiators in aqueous solutio
- Lion, Claude,Da Conceicao, Louis,Hedayatullah, Mir
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- The urea-hydrogen peroxide complex: Solid-state oxidative protocols for hydroxylated aldehydes and ketones (Dakin reaction), nitriles, sulfides, and nitrogen heterocycles
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(equation presented) An efficient solid-state oxidation of organic molecules is described using a stable, inexpensive, and easily handled reagent, the urea-hydrogen peroxide adduct. The generality of the reaction has been demonstrated in oxidation of several molecules, namely hydroxylated aldehydes and ketones (to hydroxylated phenols), sulfides (to sulfoxides and sulfones), nitriles (to amides), and nitrogen heterocycles (to N-oxides).
- Varma, Rajender S.,Naicker, Kannan P.
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p. 189 - 191
(2008/02/11)
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- Reactions of sulfides with S-330, a potential decontaminant of sulfur mustard in formulations
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Because the vesicant sulfur mustard (HD) remains a major chemical threat from either domestic terrorists or countries in conflict, topical preparations are being evaluated as protectants from HD exposure. The objective of this study was to evaluate the effectiveness of chloroamide S-330 as a potential reactive component in topical formulations. Therefore, the rate, mechanism and by-products of the oxidation reactions of sulfides by S-330 in solvent media or specific formulation vehicles were investigated. Using NMR, LC, LC-MS and GC-MS, the reactions of S-330 with HD, dibutyl sulfide (DBS) and methyl phenyl sulfide (MPS) were studied in acetonitrile, chloroform and perfluoropolyether (PFPE) oil. The oxidation of the three sulfides with S-330 was very rapid and completed in 4 min in acetonitril-water or PFPE oil, but the rates of reaction in chloroform were significantly slower. In a large excess of S-330, the major products resulted from chlorination of the side chains. At a high HD/S-330 ratio, the major product was HD sulfoxide. Under both conditions, only a trace of HD sulfone, also a blistering agent, was observed. Reactions with DBS and MPS primarily gave sulfoxides and sulfones, with less side-chain chlorination. The chloroamide S-330 appeared to be a rapid and effective decontaminant of HD in either polar media or in a PFPE oil. The two alkyl and aryl sulfides are suitable simulants of HD for the initial screening and evaluation of S-330 or other similar oxidizing agents.
- Shih, Ming L.,Korte, William D.,Smith, J. Richard,Szafraniec, Linda L.
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- Binuclear manganese complexes as catalysts in the selective and efficient oxidation of sulfides to sulfones
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The binuclear Mn(IV)-Mn(IV) manganese complex 1 catalyzes the periodic acid oxidation of sulfides to sulfones under mild conditions. The reaction was found to be highly selective giving almost quantitative yields of the sulfones even in the presence other easily oxidized groups. Only amines were found to hinder the reaction.
- Barton, Derek H. R.,Li, Wenge,Smith, Jason A.
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p. 7055 - 7058
(2007/10/03)
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- A mild, efficient and selective oxidation of sulfides to sulfoxides
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Several titanium derivatives supported on silica have been investigated as catalysts in the sulfide→sulfoxide oxidation; the supported titanium/tartaric acid catalyst is highly suited to reactions carried out with H2O2, leading to high yields and high sulfoxide/sulfone selectivities, while small asymmetric inductions (up to 13%) are observed.
- Fraile, Jose M.,Garcia, Jose I.,Lazaro, Beatriz,Mayoral, Jose A.
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p. 1807 - 1808
(2007/10/03)
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