- Preoxidation-assisted nitrogen enrichment strategy to decorate porous carbon spheres for catalytic adsorption/oxidation of methyl mercaptan
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Porous carbon spheres with high surface area and microporous structure were synthesized from alkyl phenols and formaldehyde via suspension polymerization and steam activation. The effects of air oxidation and ammonia solution heat treatment on the pore structure and surface chemistry of the carbon spheres were studied for catalytic oxidation of CH3SH. The structure property and surface chemistry of the obtained carbon spheres were characterized by N2 adsorption-desorption, FTIR, scanning electron microscopy, XRD, elemental analysis, X-ray photoelectron spectroscopy and Boehm titration, and then thermal analysis and gas chromatography-mass spectrometry were applied to investigate the catalytic oxidation product. Results show that the as-prepared microporous carbon spheres through direct ammonia treatment have a high surface area value of 1710 m2 g-1 and a total pore volume of 0.83 cm3 g-1. Moreover, the preoxidation-assisted nitrogen enrichment strategy not only increases the surface area and total pore volume of the carbon spheres, but also introduces more active nitrogen species such as pyridinic nitrogen and quaternary nitrogen, leading to the highest nitrogen content of 7.13 wt% and the highest CH3SH capacity of 622.8 mg g-1 due to the pyridinic nitrogen and quaternary nitrogen as function of catalysts. In addition, water and oxygen have a beneficial effect on CH3SH oxidation over the nitrogen modified carbon spheres, and the basic oxidation product is CH3SSCH3 that can be further oxidized into CH3SO2SCH3 according to DTG and GC/MS analysis. The great recycling stability after ten cycles with a reserved CH3SH capacity of 97% demonstrates that the porous carbon spheres obtained by preoxidation-assisted enriched nitrogen strategy are promising for catalytic oxidation of CH3SH. This journal is
- Fan, Caimei,Kou, Lifang,Li, Rui,Wang, Rongxian,Wang, Yaqi,Zhang, Changming,Zhang, Xiaochao
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Read Online
- A novel practical preparation of methyl methanethiosulfonate from dimethyl sulfoxide initiated by a catalytic amount of (COCl)2 or anhydrous HCl
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A novel practical preparation method for methyl methanethiosulfonate (MMTS) has been developed. Dimethyl sulfoxide was converted to MMTS in the presence of a catalytic amount of oxalyl chloride or anhydrous HCl in acetonitrile under reflux in an ideal yield. Methanesulfenic acid was proposed to be the key intermediate for the formation of MMTS.
- Huang, Shuai,Wang, Hao,Liu, Yongguo,Sun, Baoguo,Tian, Hongyu,Liang, Sen
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Read Online
- Acid Promoted Direct Cross-Coupling of Methyl Ketones with Dimethyl Sulfoxide: Access to Ketoallyl Methylsulfides and -sulfones
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A new strategy to prepare β-acyl allylic methylsulfides and -sulfones through acid promoted direct cross-coupling of methyl ketones with dimethyl sulfoxide (DMSO) is reported. The reaction proceeded through the nucleophilic attack of enamine intermidiates derived from ketones to in situ generated thionium ion species, followed by elimination of methanthiol to give ketoallylic methylsulfides. With the prolonged reaction time, such products could be further reacted with a methyl sulfonyl radical, which might be generated from a methylthiosulfonate species, to afford ketoallylic methylsulfones in high yields. Molecular transformations of the allylic methylsulfides were also demonstrated.
- Wen, Zhen-Kang,Liu, Xue-Hua,Liu, Yu-Fang,Chao, Jian-Bin
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Read Online
- Antioxidant activity of two edible isothiocyanates: Sulforaphane and erucin is due to their thermal decomposition to sulfenic acids and methylsulfinyl radicals
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Sulforaphane (SFN) and erucin (ERN) are isothiocyanates (ITCs) bearing, respectively, methylsulfinyl and methylsulfanyl groups. Their chemopreventive and anticancer activity is attributed to ability to modulate cellular redox status due to induction of Phase 2 cytoprotective enzymes (indirect antioxidant action) but many attempts to connect the bioactivity of ITCs with their radical trapping activity failed. Both ITCs are evolved from their glucosinolates during food processing of Cruciferous vegetables, therefore, we studied antioxidant behaviour of SFN/ERN at elevated temperature in two lipid systems. Neither ERN nor SFN inhibit the oxidation of bulk linolenic acid (below 100 °C) but both ITCs increase oxidative stability of soy lecithin (above 150 °C). On the basis of GC-MS analysis we verified our preliminary hypothesis (Antioxidants 2020, 9, 1090) about participation of sulfenic acids and methylsulfinyl radicals as radical trapping agents responsible for the antioxidant effect of edible ITCs during thermal oxidation of lipids at elevated temperatures (above 140 °C).
- Cedrowski, Jakub,D?browa, Kajetan,Przybylski, Pawe?,Krogul-Sobczak, Agnieszka,Litwinienko, Grzegorz
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- Temperature-Controlled Chemoselective Synthesis of Thiosulfonates and Thiocyanates: Novel Reactivity of KXCN (X=S, Se) towards Organosulfonyl Chlorides
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An efficient chemoselective protocol has been developed for the synthesis of thiosulfonates and thiocyanates by employing cost effective and commercially available organosulfonyl chlorides with potassium thio-/selenocyanate. The strategy offered the thiosulfonates and thiocyanates selectively by tuning the equivalents of KSeCN and optimizing the reaction temperature. On the other hand, thiosulfonates were obtained as sole products when organosulfonyl chlorides were treated with KSCN. Furthermore, the syntheses of diarylthioethers and aryl(heteroaryl) thioethers were carried out as a part of synthetic application of newly prepared arylthiocyanates.
- Kalaramna, Pratibha,Goswami, Avijit
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supporting information
p. 5359 - 5366
(2021/10/25)
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- The organocatalytic synthesis of perfluorophenylsulfides: Via the thiolation of trimethyl(perfluorophenyl)silanes and thiosulfonates
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The organic superbase t-Bu-P4-catalyzed direct thiolation of trimethyl(perfluorophenyl)silanes and thiosulfonates was developed. Yields of perfluorophenylsulfides of up to 97% under catalysis of 5 mol% t-Bu-P4 were achieved. This method was shown to provide an efficient way to construct the perfluorophenyl-sulfur bond under mild metal-free reaction conditions. This journal is
- Cai, Zhihua,Du, Guangfen,He, Lin,Lin, Muze,Luo, Jinyun,Wu, Leifang
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supporting information
p. 9237 - 9241
(2021/11/13)
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- Simple preparation method of methyl thiomethanesulfonate
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The invention provides a simple and convenient preparation method of methyl thiomethanesulfonate with a structure as shown in a formula (I). The method comprises the following steps: dropwise adding acatalytic amount of an acetonitrile solution of oxalyl chloride into the acetonitrile solution of dimethyl sulfoxide at about 0 DEG C; after dropwise adding, heating and refluxing a reaction mixture;after the reaction is finished, concentrating a reaction mixture, and obtaining methyl thiomethanesulfonate column chromatography separation; and the yield is 94%.
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Paragraph 0004; 0009
(2020/05/08)
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- CuCl2-promoted decomposition of sulfonyl hydrazides for the synthesis of thiosulfonates
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Sulfonyl hydrazides recently received much attention as reagents for the introduction of sulfur-containing functional groups into organic compounds, because both sulfonyl and sulfenyl sources could be generated by the oxidation and decomposition of the sulfonyl hydrazides, respectively. However, the transformations of sulfonyl hydrazides into thiosulfonates, which could be produced by the reaction between sulfonyl and sulfenyl sources, have been less investigated. In this manuscript, we describe CuCl2-promoted selective synthesis of thiosulfonates from sulfonyl hydrazides. A variety of thiosulfonates were produced in moderate to good yields. The mechanism involving radical intermediates such as sulfonyl radical and thiyl radical was proposed on the basis of the previously reported references and mechanistic investigations. In addition, quantum chemical simulations revealed that Cu-promoted decomposition of sulfonyl hydrazides is thermodynamically viable in the developed conditions.
- Kim, Junsu,Park, Sanggil,Kim, Hyungjun,Kim, Jinho
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supporting information
(2020/07/02)
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- Preparation method of thiosulfonate compounds in aqueous phase
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The invention relates to a preparation method of thiosulfonate compounds in an aqueous phase. The preparation method comprises adding sulfonyl hydrazide, an accelerant, an oxidant and solvent water into a Schlenk reaction bottle, stirring to allow to react under certain temperature and air atmosphere, and carrying out free radical coupling reaction to obtain the thiosulfonate compounds.
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Paragraph 0075-0077
(2019/06/27)
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- External Oxidant-Free Oxidative Tandem Cyclization: NaI-Catalyzed Thiolation for the Synthesis of 3-Thiosubstituted Pyrroles
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A simple method for the synthesis of 3-thiosubstituted pyrroles from homopropargylic amines and thiosulfonates via a tandem sulfenylation/cyclization has been developed. The thiosulfonates are used both as substrates and oxidants in this transformation. This procedure exhibits good functional group tolerance and a series of 3-thiosubstituted pyrrole derivatives was obtained in moderate to good yields. (Figure presented.).
- Yuan, Bingxiang,Jiang, Yong,Qi, Zhenjie,Guan, Xin,Wang, Ting,Yan, Rulong
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supporting information
p. 5112 - 5117
(2019/11/11)
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- Transition-Metal-Free Synthesis of Thiosulfonates through Radical Coupling Reaction
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An efficient and practical transition-metal-free radical coupling reaction of sulfonyl hydrazides mediated by NIS/K 2 S 2 O 8 has been developed to afford a variety of biological activity thiosulfonates in moderate to excellent yields. Compared to a known approach for the synthesis of thiosulfonates from sulfonyl hydrazides, this strategy features high yields, mild reaction conditions, and broad substrate scope. The mechanistic studies revealed that the procedure undergoes via a radical cross-coupling process for the construction of S-S bonds.
- Zhou, Guodong,Xu, Xu-Dong,Chen, Gan-Ping,Wei, Wen-Ting,Guo, Zhiyong
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supporting information
p. 2076 - 2080
(2018/09/18)
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- Direct Syn Addition of Two Silicon Atoms to a C≡C Triple Bond by Si?Si Bond Activation: Access to Reactive Disilylated Olefins
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A catalytic intramolecular silapalladation of alkynes affords, in good yields and stereoselectively, syn-disilylated heterocycles of different chemical structure and size. When applied to silylethers, this reaction leads to vinylic silanols that undergo a rhodium-catalyzed addition to activated olefins, providing the oxa-Heck or oxa-Michael products, depending on the reaction conditions.
- Ahmad, Maha,Gaumont, Annie-Claude,Durandetti, Muriel,Maddaluno, Jacques
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supporting information
p. 2464 - 2468
(2017/02/23)
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- Experimental study on deep desulfurization of MTBE by electrochemical oxidation and distillation
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With the increasing awareness of environmental protection, deep desulfurization of methyl tert-butyl ether (MTBE), which is the most important octane booster in gasoline, is extremely urgent. Herein, a new desulfurization method, involving the combination of electrochemical oxidation and distillation, is proposed to reduce the sulfur content in MTBE. Under optimum operating conditions, the sulfur content of real MTBE decreases from 132.5 μg g-1 to 2.3 μg g-1 and the desulfurization efficiency reaches 98.25%. The oxidation products with high boiling points can be separated by distillation. FTIR analyses prove that electrochemical oxidation has no influence on the main properties of MTBE. Moreover, GC/MS is used to study the conversion of model organic sulfides (dimethyl disulfide, diethyl sulfide and butyl mercaptan) in the electrochemical oxidative desulfurization process. Finally, the possible reaction mechanism of the electrochemical oxidative desulfurization of MTBE is proposed.
- Li, Jing-Jing,Zhou, Fei,Tang, Xiao-Dong,Hu, Tao,Cheng, Jin
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p. 4803 - 4809
(2016/01/29)
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- Fast and efficient green synthesis of thiosulfonate S-esters by microwave-supported permanganate oxidation of symmetrical disulfides
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Potassium permanganate absorbed on copper(II) sulfate pentahydrate has been found to be an efficient, inexpensive, and green oxidation agent for the synthesis of "symmetrical" thiosulfonate S-esters by oxidation of the corresponding symmetrical disulfides. The oxidation reactions were carried out under solvent-free reaction conditions within 15 min under the influence of microwave irradiation, as well as (for comparison) supported by conventional heating, to afford yields of the thiosulfonate S-esters in the range of 60-83%. The oxidation reaction appears to proceed (at least partly) via an intermediate symmetrical vic-disulfoxide.
- Luu, Thi Xuan Thi,Nguyen, Thao-Tran Thi,Le, Thach Ngoc,Spanget-Larsen, Jens,Duus, Fritz
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p. 340 - 350
(2015/04/27)
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- Sulfur containing compounds
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This invention is directed to novel and known stufur containing compounds and pharmaceutically acceptable salts thereof that have utility as antifungals and as antiproliferative agents against mammalian cells, in particular cancer cells and most particularly leukemia-derived cells. The invention provides a method for synthesizing certain of the sulfur containing compounds that is more efficient than previously known methods.
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Page/Page column 27
(2010/11/30)
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- Thermal degradation of sulforaphane in aqueous solution
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Sulforaphane, a cancer chemopreventive agent identified from broccoli, was degraded in an aqueous solution at 50 and 100 °C. The reaction mixtures were extracted with methylene chloride and analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Dimethyl disulfide, S- methyl methylthiosulfinate, S-methyl methylthiosulfonate, methyl (methylthio)methyl disulfide, 1,2,4-trithiolane, 4-isothiocyanato-1- (methylthio)-1-butene, and 3-butenyl isothiocyanate were identified as volatile decomposition products. After methylene chloride extraction, the aqueous layer was dried and silica gel column chromatography was used to separate and purify the nonvolatile decomposition products. The major thermal degradation compound was determined by 1H NMR, 13C NMR, and FAB-MS as N,N'-di(4-methylsulfinyl)butyl thiourea. A possible mechanism for the formation of these products is proposed.
- Jin, Yi,Wang, Mingfu,Rosen, Robert T.,Ho, Chi-Tang
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p. 3121 - 3123
(2007/10/03)
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- An easy and practical synthesis of symmetrical thiosulfonic S-esters
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Symmetrical alkyl and aryl thiosulfonic S-esters were prepared in good to excellent yields by the acetyl chloride-activated zinc reduction of sulfonyl chlorides.
- Chemla, Fabrice
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p. 894 - 896
(2007/10/03)
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- Unsensitized photooxidation of sulfur compounds with molecular oxygen in solution
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The short wavelength irradiation of aliphatic disulfides, sulfides and of n-butanethiol in alcohols or aqueous acetonitrile in the presence of oxygen was investigated: the corresponding sulfonic acids are produced in good yields for short alkyl chain compounds, together with smaller amounts of sulfuric and carboxylic acids. In acetonitrile, the influence of added water on the reaction course is evidenced: increased reaction rate and acid yields, control of sulfuric acid formation. Intermediates such as sulfinic acid and thiosulfonate were detected and their rates of formation were monitored. The reaction appears to involve thiyl radicals giving rise to sulfonyl radicals in the presence of oxygen. A first tentative hypothesis concerning the mechanism is advanced.
- Robert-Banchereau, Evelyne,Lacombe, Sylvie,Ollivier, Jean
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p. 2087 - 2102
(2007/10/03)
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- Solution reactivity of thiyl radicals with molecular oxygen: Unsensitized photooxidation of dimethyldisulfide
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Irradiation of dimethyldisulfide in a protic solvent in the presence of molecular oxygen leads to the formation of sulfonic and sulfuric acids as major products. The addition of molecular oxygen on the thiyl radical formed by S-S bond cleavage is postulated.
- Banchereau, Evelyne,Lacombe, Sylvie,Ollivier, Jean
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p. 8197 - 8200
(2007/10/02)
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- Synthesis of Trimethyl α-Keto Trithioorthoesters and Dimethyl α-Keto Dithioacetals by Reaction of Esters with Tris(methylthio)methyllithium
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A complete study has been made of the reaction of tris(methylthio)methyllithium with aromatic, heteroaromatic, and aliphatic esters.It is a one-pot reaction that despite its complexity, and depending on the reagent ratios, the reaction conditions, and the possible use of additional reagents (N-(methylthio)phthalimide or BuLi), can supply easily, in excellent and reproducible yields, the trimethyl α-keto trithioorthoesters 3 or, alternatively, the dimethyl α-keto dithioacetals 4.The reaction mechanism has been elucidated.
- Barbero, Margherita,Cadamuro, Silvano,Degani, Iacopo,Dughera, Stefano,Fochi, Rita
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p. 6017 - 6024
(2007/10/03)
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- OXIDATION OF DISULPHIDES BY HYDROGEN PEROXIDE IN THE PRESENCE OF SUBSTITUTED PHTHALOCYANINES OF TRANSITION METALS
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A study has been made of the oxidation of disulphides of different structure by hydrogen peroxide in the presence of nitrosubstituted phthalocyanines of transition metals.It has been established that phthalocyanines in a homophase system ensure a higher initial oxidation rate of disulphides to disulphones and thiosulphonates than Na2WO4 in a two-phase system with the use of interphase transfer catalysts.
- Anisimov, A. V.,Mohammed, R. A.,Borisenkova, S. A.,Tarakanova, A. V.,Barkanova, S. V.,Et Al.
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p. 347 - 352
(2007/10/02)
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- OXIDATION OF DISULPHIDES BY HYDROGEN PEROXIDE UNDER INTERPHASE CATALYSIS CONDITIONS
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It has been shown that aliphatic and aromatic disulphides are oxidized by hydrogen peroxide in the presence of sodium tungstate and molybdate and an interphase catalyst to the corresponding thiolsulphonates and disulphones.The structure of the oxidation products depends on the interphase catalyst used: in the presence of triethylbenzylammoniumbromide, thiosulphonates are formed, while in the presence of cetyltrimethylammoniumbromide, disulphones are formed.The main reason for this difference is the solubility in the organic phase of the intermediate peroxy complex formed by the reaction of hydrogen peroxide with the metal compound in the presence of phosphoric acid.The rate of the reaction and the yields of oxidation products depend on the temperature, the solvent used and the ratio of the reactants.
- Anisimov, A. V.,Mohammed, R. A.,Tarakanova, A. V.,Borisenkova, S. A.
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p. 407 - 412
(2007/10/02)
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- Photooxidations of Sulfenic Acid Derivatives 2. A Remarkable Solvent Effect on the Reactions of Singlet Oxygen with Disulfides.
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Photooxidations of a series of 9 disulfides reveal that the thiosulfinate/thiosulfonate product ratios can be dramatically influenced by the nature of the solvent.The unique ability of methanol to influence this ratio is attributed to nucleophilic addition to a thiopersulfoxide intermediate.
- Clennan, Edward L.,Wang, Dongyi,Zhang, Houwen,Clifton, Christine H.
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p. 4723 - 4726
(2007/10/02)
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- SYNTHESES DE CYCLOHEXENONES α-SUBSTITUEES VIA LA THERMOLYSE DE CETOSULFOXYDES TERTIAIRES
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The sulfenylation-dehydrosulfenylation method, combined with carbon-carbon bond forming reactions, has been applied to the synthesis of some α-functionalized cyclohexenones 3.Hence, the sodium anion of the 2-methylthiocyclohexanone in THF reacts with primary, allyl and benzyl halides as well as with Michael acceptors to lead to the tertiary ketosulfides 1a-j.Further oxidation by NaIO4 and thermolysis in boiling toluene of the resulting sulfoxides 2 have been performed.The scope and limitations of this strategy are also discussed. Key Words: α-functionalized cyclohexenones; tertiary ketosulfides and ketosulfoxides; sulfenylation and deshydrosulfenylation; thermolysis.
- Barillier, Daniel,Benhida, Rachid,Vazeux, Michel
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- Preparation of alkyl alkanethiolsulfonates
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Alkyl alkanethiolsulfonates are prepared by oxidation of the corresponding alkanethiol, dialkyl disulfide, or mixture thereof by aqueous hydrogen peroxide in the presence of a Group VIII transition metal catalyst.
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- Zwitterion-accelerated -Sigmatropic Rearrangements and -Sigmatropic Rearrangements of Sulphoxides and Amine Oxides
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The effect of a zwitterionic moiety on -sigmatropic rearrangements has been studied.The allyl vinyl sulphoxide 5 underwent a -sigmatropic rearrangement at 23 deg C under neutral conditions to give the thione S-oxide 6 (96percent).This rearrangement (k1 = 1.56 +/- 0.04 x 10-1 h-1) was 45 times faster than conversion of the corresponding sulphide 3 into the thione 4 ( k1 = 3.5 +/- 0.1 x 10-3 h-1).At 23 deg C, the sulphoxide 7 also rearranged to give a mixture of (E)- and (Z)-thial S-oxide 8 (90percent).These experiments showed that the accelerating effect of the charges in the sulphoxide, a zwitterionic moiety, did not cancel out.Instead, the sulphoxide moiety significantly facilitated the -sigmatropic rearrangement.In the thermolysis of hexa-1,5-dienes with a zwitterionic moiety attached to the C-3 position ( e.g., 9 and 24), -sigmatropic rearrangements occurred.The conversion of the allyl sulphoxide 21 into the corresponding sulphenate ester 22 by a process was used as the key step in a total synthesis of yomogi alcohol 23, a biologically active monoterpenoid.
- Hwu, Jih Ru,Anderson, Denise A.
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p. 3199 - 3206
(2007/10/02)
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- An Electrochemical Preparation of Methyl Methanethiolsulfonate
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Methyl methanethiolsulfonate is conveniently prepared, in good yields, by electrochemical oxidation of dimethyl disulfide, in aqueous acetonitrile, at constant current.
- Machion, Pedro D.,Pardini, Vera L.,Viertler, Hans
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p. 365 - 370
(2007/10/02)
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- Analysis of Radicals from Flames by Scavenging with Dimethyl Disulfide
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Larger hydrocarbon radicals in flames, which are difficult to detect by optical methods, can be analyzed quantitatively by radical scavenging with dimethyl disulfide in the condensed phase. - Gas samples taken from a sooting ethyne/oxygen flame by a nozzle beam were frozen at liquid-N2-temperature on the inner surface of a hollow sphere simultaneously with the radical scavenger dimethyl disulfide.The latter was admitted in large excess as a gas and was condensed uniformly on the inner wall of the sphere.The mixture of condensable stable flame products and scavenging products in the excess CH3SSCH3 was separated and identified by GC/MS. - Larger hydrocarbons (CxHy, x >= 6) condensed quantitatively.H, CH3, C4H3 and the phenyl radical were scavenged as mono(methylthio) compounds; C2 and the carbenes CH2, C3H2, C5H2 yielded bis(methylthio) compounds; other bis(methylthio) compounds observed were C2nH2(SCH3)2 with n = 1, 2, 3 and 4.CH, C3H and C2H3 were identified by the respective tris(methylthio) compounds.Any consecutive reactions of radicals with stable flame products and their recombinations in the cold trap were supressed by their scavenging reaction.
- Hausmann, M.,Homann, K. H.
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p. 1308 - 1312
(2007/10/02)
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- S-Alkyl Alkanesulfonothioates and S-1-Chloroalkyl Alkanesulfonothioates from Linear Alkanesulfinyl Chlorides
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Treatment of linear alkanesulfinyl chlorides 1 with dry N,N-dimethylmethanamide (DMF), N,N-dimethylethanamide (DMA), or 1-methyl-2-pyrrolidone (NMP) in an inert atmosphere, with or without added solvent, gives S-alkyl alkanesulfonothioates 4 (minor products) and S-1-chloroalkyl alkanesulfonothioates 5.The yield of 4 is decreased in the presence of the radical inhibitor 1,4-dihydroxybenzene.Evidence has been obtained for the formation and trapping of sulfines (including methanethial S-oxide) and for formation of sulfinyl radicals, vic-disulfoxides (α-disulfoxides), and O,S-sulfenyl sulfinates as reaction intermediates.S-Phenyl benzenesulfonothioate is a major product from the reaction of alkanesulfinyl chlorides and benzenesulfinyl chloride in the presence of DMF.
- Freeman, Fillmore,Keindl, Monica C.
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p. 2026 - 2031
(2007/10/02)
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- SCAVENGING OF RADICALS FROM THE GAS PHASE BY FREEZING WITH DIMETHYL DISULFIDE: 1. TEST OF THE METHOD FOR LIGHT RADICALS.
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H and O atoms and methyl radicals produced in microwave discharges of H//2/He, O//2/He and CH//4/He mixtures, respectively, were scavenged by supersonic nozzle probing with subsequent freezing and reaction with dimethyl disulfide on a liquid nitrogen cooled wall. The main reaction products for the three kinds of radicals were CH//3SH, CH//3S(O)SCH//3 and CH//3SCH//3, respectively. The scavenging efficiencies for the different radicals were determined and measured as a function of the gas phase radical concentration, the flow of scavenger molecules, the pressure in the vacuum chamber, and the conditions of the discharge and the flow through the sampling nozzle. It is concluded that this method is suitable for light radicals with reservations in the case of H atoms and can probably be used with still better success for heavier radicals.
- Schottler,Homann
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p. 688 - 694
(2007/10/02)
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- SCAVENGING OF RADICALS FROM THE GAS PHASE BY FREEZING WITH DIMETHYL DISULFIDE: 2. RADICALS FROM DISCHARGES AND A FLAME OF ACETYLENE.
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The method of detecting radicals from low-pressure gas-phase systems by scavenging with dimethyl disulfide (DMD) has been applied to microwave discharges in C//2H//2/He mixtures and to a C//2H//2/O//2 flame. It was accomplished by condensing a supersonic nozzle beam from the reaction system together with a beam of DMD on a liquid-N//2 cooled surface. The scavenging products were measured by GC/MS after warming-up. Radicals measured in the discharge were C//2H, C//4H, C//6H, C//3H//2, C//2 besides H atoms. Preliminary measurements on the flame showed that C//6H//5 (phenyl), CH//2, C//3H//2, besides H and O atoms were prominent radicals at the end of the oxidation zone. The concentration of phenyl is of the same order as that of e. g. naphthalene.
- Kubitza,Schottler,Homann
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p. 695 - 700
(2007/10/02)
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- Observation of Intermediates during the Reaction of Linear Alkanesulfinyl Chlorides with Activated Zerovalent Zinc
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Methane- (2), ethane- (3), propane- (4), butane (5), pentane- (6), hexane- (7), octane- (8), and dodecanesulfinyl chloride (9) reacted with activated zinc to give the corresponding alkanesulfonothioic S-alkyl esters (12-19) in 40-89percent yield.The reaction of methanesulfinyl chloride (2) with activated zerovalent zinc under nitrogen in anhydrous diethyl ether at -30, -20, and 0 deg C was investigated by 1H NMR and 13C NMR spectroscopy.The 13C NMR spectrum of the partially converted -30 deg C reaction mixture showed the presence of methanesulfinyl chloride (2), S-methyl methanesulf onothioate (12), methanesulfinic acid (24) or zinc methanesulfinate (25), methanesulfonyl chloride (26), dimethyl sulfide (27), S-methyl methanesulfinothioate (28), and methanesulfinyl methyl sulfone (29). vic-Dimethyl disulfoxides (31) and OS-methyl methanesulfino(thioperoxoates) (32) are proposed as two of several transient reaction intermediates.
- Freeman, Fillmore,Angeletakis, Christos N.,Keindl, Monica C.
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p. 454 - 458
(2007/10/02)
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- Evidence for Methanethial S-Oxide during the Reaction of Methanesulphinyl Chloride and N,N-Dimethylmethanamide (DMF)
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Methanethial S-oxide was intercepted as an intermediate during the reaction of methanesulphinyl chloride and N,N-dimethylmethaneamide (DMF), which afforded S-methyl methanesulphonothioate and S-(chloromethyl) methanesulphonothioate.
- Freeman, Fillmore,Keindl, Monica C.
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p. 138 - 139
(2007/10/02)
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- STRUCTURE AND CONFORMATION OF SYMMETRIC ARYL THIOSULPHONIC ESTERS
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The symmetric thiosulphonic esters R-SO2-S-R (R = CH3, C6H5, p-CH3-C6H4, p-CH3O-C6H4, p-Cl-C6H4, 2,4,6-(CH3)3-C6H2, 2,4,6-(i-C3H7)3-C6H2) have been prepared by a one-step synthesis partially reducing the sulphonyl chlorides with KI in the presence of catalytic amounts of pyridine.The crystal structures of the aryl derivatives X-C6H4-SO2-S-C6H4-X (X = H, CH3, Cl) have been determined using single crystal X-ray diffractometric data: C6H5-SO2-S-C6H5 (MoKα): P2/n, a = 12.413(4), b = 8.537(2), c = 12.649(5) Angstroem, β = 116.50(2) deg, Z = 4, final R = 0.0485; CH3-C6H4-SO2-S-C6H4-CH3 (CuKα): P21/n, a = 13.932(6), b = 12.076(6), c = 8.326(4) Angstroem, β = 93.40(6) deg, Z = 4, final R = 0.0425; Cl-C6H4-SO2-S-C6H4-Cl (MoKα): P21/n, a = 13.716(9), b = 11.932(8), c = 8.206(4) Angstroem, β = 92.47(2) deg, Z = 4, final R = 0.0493.The three structures are strictly similar with a conformation of the thiosulphonyl system essentially determined by the tendency of the non bonding electron pairs of S(II) to assume synclinal and antiperiplanar conformation with respect to the S(VI)-O bonds.The repulsion exerted by these pairs on the S(II)-C and S(II)-S(VI) bonding pairs justifies the narrowing of the S(VI)-S(II)-C angle with respect to the tetrahedral value.Electronic effects due to the para substituents in the phenyl rings superimpose that repulsion producing a different narrowing in the three derivatives.These effects influence also the S(VI)-S(II) distance which is shorter in the case of X = H, where the angle S(VI)-S(II)-C is larger.The angular deformations of the environment of S(VI) make the two oxygen atoms non equivalent, so that S(VI) is chiral.
- Caputo, Romualdo,Palumbo, Giovanni,Nardelli, Mario,Pelizzi, Giancarlo
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p. 421 - 430
(2007/10/02)
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- Mechanism of the reaction of oxygen atoms, O(3P) with dimethyl disulfide
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The mechanism of the reaction of ground state oxygen atoms, O(3P), with CH3SSCH3 was studied by analysis of the final products.Oxygen atoms were generated by mercury photosensitized decomposition of N2O such that >> .The only detected product was CH3S(O)2SCH3, which accounted for close to 70percent of the oxygen atoms reacted.Isomerization of small amounts of cis- or trans-2-butene added to the reaction mixture indicated the presence of CH3 radicals.The results are consistent with the primary reaction O + CH3SSCH3 -> CH3SO + CH3S.The effect of small amounts of CH3SH and H2S on the yields of CH3S(O)2SCH3 and the products formed provide further information on the nature of the secondary chemistry.A comprehensive reaction mechanism has been proposed.
- Singleton, D. L.,Irwin, R. S.,Cvetanovic, R. J.
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p. 968 - 974
(2007/10/02)
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- Formation of α-Disulfoxides, Sulfinic Anhydrides, and Sulfines during the m-Chloroperoxybenzoic Acid Oxidation of Symmetrical S-Alkyl Alkanethiosulfinates
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The m-chloroperoxybenzoic acid (MCPBA) oxidation of S-methyl methanethiosulfinate (33), S-propyl propanethiosulfinate (34), S-2-propyl 2-propanethiosulfinate (35), S-butyl butanethiosulfinate (36), and S-(phenylmethyl)phenylmethanethiosulfinate (37) has been at low temperatures and compared with the MCPBA oxidation of S-(2-methyl-2-propyl)-2-methyl-2-propanethiosulfinate (26) and S-(2,2-dimethylpropyl)-2,2-dimethylpropanethiosulfinate (30).Diastereomeric α-disulfoxides are observed with 33-36 at -40 deg C, sulfinic anhydrides are observed with 33, 35, and 36 at -40 deg C, and sulfines are observed on warming the product mixtures from 34-37 from -40 deg C to -20 deg C.The lachrymatory factor ((Z)-propanethial S-oxide, 47) of the onion was observed during the oxidation of 35.The absence of thiosulfonates at -40 deg C and their presence at higher temperature suggest that they are not formed in the initial oxidation process but from subsequent reactions of thiosulfinates and sulfinic acids.Various mechanisms for the formation of intermediates and products are discussed.
- Freeman, Fillmore,Angeletakis, Christos N.
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p. 4039 - 4049
(2007/10/02)
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- A NOVEL METHOD FOR PREPARATION OF 2-(METHYL- OR PHENYLTHIO)ALKANOIC ESTERS
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Ethyl 2-acetylalkanoate gave ethyl 2-(methyl- or phenylthio)alkanoate in high yield on treatment with CH3SSO2CH3, PhSSO2Ph, or PhSSPh in the presence of small excess of EtONa in EtOH.Application of the present method to synthesis of pellitorine and thr queen substance is also described.
- Ogura, Katsuyuki,Sanada, Kunio,Takahashi, Kazumasa,Iida, Hirotada
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p. 4035 - 4038
(2007/10/02)
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- UNKNOWN REACTIONS OF POLYCHLORINATED CYCLOPENTENONES WITH DIMETHYL SULFOXIDE
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It was shown that perchloro-2-cyclopenten-1-one, perchloro-2-cyclopentene-1,4-dione, perchloro-2,5-dihydrofuran-2-one, perchloroindenone, and 2,3,4,4,5-pentachloro-2-cyclopenten-1-one enter into the Pummerer reaction with dimethyl sulfoxide like acid chlorides.
- Maslennikov, E. I.,Talzi, V. P.,Gunbin, V. N.,Yasman, Ya. B.,Gudoshnikov, S. K.
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p. 2258 - 2260
(2007/10/02)
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- Oxidation of Unsymmetrical Disulfide and Thiosulfinic S-Esters with Peroxy Acids. Search for Formation of α-Disulfoxide as An Intermediate in the Electrophilic Oxidation of Thiosulfinic S-Ester
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Oxidation of an unsymmetrical disulfide, methyl phenyl disulfide, with peroxy acids takes place mainly at more electron-rich sulfur atom to form thiosulfinic S-ester at the first stage, while oxidation of unsymmetrical thiosulfinic S-ester with peroxy acids gives usually four thiosulfonic S-esters, together with sulfinic and sulfonic acids, further oxidation products.Oxidation of S-methyl benzenethiosulfinate 6 affords, as one of the products, S-phenyl methanethiosulfonate 11, in which the original sulfinyl oxygen is brought into methanesulfonyl group.A small amount of S-phenyl benzenethiosulfonate 9 (or benzenesulfonic acid 15) is obtained in the oxidation of S-phenyl methanethiosulfinate 7. 18O-Label of the starting thiosulfinic S-ester 6 was found to be incorporated to some extents into all four products, i.e. 8-11, while a part of 18O-label of S-phenyl methanethiosulfinate 7 was also observed in S-phenyl benzenethiosulfonate 9 and benzensulfonic acid 15, although most of 18O-label of 7 was incorporated into S-phenyl methanethiosulfonate 11.Thiosulfinic S-esters are stable and do not undergo disproportionation and 18O-exchange under the conditions.These observations suggest the formation of α-disulfoxide as an intermediate in the oxidation of thiosulfinic S-ester to thiosulfonic S-ester, especially in the oxidation of 6, although no peak corresponding to α-disulfoxide was observed directly in the NMR spectra taken during the oxidations of a few thiosulfinic S-esters with peroxy acid.Mechanism of the oxidation is discussed.
- Oae, Shigeru,Takata, Toshikazu,Kim, Yong Hae
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p. 2484 - 2494
(2007/10/02)
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- REACTION OF THIOLSULFINATES WITH TRIHALOACETIC ANHYDRIDES-I EVIDENCE FOR THE FORMATION OF SULFENYL AND SULFINYL CARBOXYLATES
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Thiosulfinates react with trifluoro- or trichloroacetic anhydride to give equimolar mixtures of the coresponding disulfides and sulfinyl trifluoro- or trichloroacetates which are in equilibria with sulfenyl carboxylates.Although the equilibrium lies far toward sulfinyl carboxylates at room temperature, addition of olefins to the mixed solution of sulfinyl carboxylate and corresponding disulfide affords the adducts which are formed in the reaction between the corresponding sulfenyl carboxylates and the olefins.Meanwhile, treatment of carboxylic acid silver salts with sulfinyl chlorides also gives sulfinyl carboxylates, howevver, sulfinyl carboxylates have not been successfully isolated yet.
- Morishita, Tsuyoshy,Furukawa, Naomichi,Oae, Shigeru
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p. 3115 - 3120
(2007/10/02)
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- Selective Oxidation of Unsymmetrical Thiosulfinic S-Esters to the Corresponding Thiosulfonic S-Esters with NaIO4
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Unsymmetrical thiosulfinic S-esters were oxidized with sodium metaperiodate in aqueous media to the corresponding unsymmetrical thiosulfonic S-esters nearly quantitatively.The oxidation was accelerated by addition of a catalytic amount of inorganic and organic acids or halogen.Sulfinic esters were produced competitively along with the thiosulfonic S-esters in the oxidation of thiosulfinic S-esters in aqueous alcohol.However, unsymmetrical disulfides were not oxidized selectively to the corresponding unsymmetrical thiosufonic S-esters but a mixture of the both symmetrical and unsymmetrical thiosulfonic S-esters was obtained.
- Takata, Toshikazu,Kim, Yong Hae,Oae, Shigeru
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p. 1443 - 1447
(2007/10/02)
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- Studies of Sulfinyl Radicals. 1. Thermal Decompositions of Benzhydryl p-Tolyl Sulfoxide and Benzhydryl Methyl Sulfoxide
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The kinetics and mechanism of the thermal decompositions of benzhydryl p-tolyl sulfoxide (BTSO) and benzhydryl methyl sulfoxide (BMSO) were studied.Product analysis, ESR, and CIDNP results showed that both sulfoxides gave p-toluenesulfinyl and methanesulfinyl radicals, respectively, by the scission of carbon-sulfur bonds at 100-130 deg C.The presence of a small amount of a base such as pyridine has been found to suppress the formation of other products than the coupling products (the corresponding thiosulfonates and tetraphenylethane), which may be formed by ionic reactions of BTSO and BMSO.The mechanism of BTSO decomposition is complex, since it is in equilibrium with benzhydryl p-toluenesulfenate (BTSN) at 100-130 deg C.On the other hand, BMSO, showing simple decomposition behavior, indicated that the decomposition rates decreased on the addition of hydroxylic solvents.
- Mizuno, Hajime,Matsuda, Minoru,Iino, Masashi
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p. 520 - 525
(2007/10/02)
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