- Bromonitromethane, a Versatile Electrophile: Reactions with Thiolates
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Thiolate ions react with bromonitromethane to give nitronate ion and, initially, sulphenyl bromide which reacts with further thiolate ion to give disulphide; when the disulphide bears an appropriately placed nitrile function, intramolecular attack by the nitronate ion at this function and subsequent intramolecular displacement of thiolate ion yields aminothiophenes.
- Fishwick, Brian R.,Rowles, David K.,Stirling, Charles J. M.
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- Synthesis and structural study of 1-(N,N-diethylamino)-2,2-bis(2-nitrophenylthio)ethene
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The synthesis, variable temperature NMR spectra, and crystal structures of two crystalline forms, 2a and 2b, of the enamine 1-(N,N-diethylamino)-2,2-bis(2-nitrophenylthio)ethene have been obtained. Both forms crystallize in the monoclinic space group P21/a. The two phases have similar molecular structures but possess different intermolecular C - H ... O hydrogen bonding interactions. Both forms exhibit disorder within the NEt2 fragment at 298 K: sufficient disorder persisted with 2a (orange needles) down to 100 K to make the geometric parameters pertaining to the enamine fragment unreliable. The disorder was effectively eliminated on cooling 2b down (red colored blocks) to 150 K. Cell dimensions for the 2a-phase are at 100 K: a = 11.1030(4) A, b = 15.1325(7) A, c = 12.4504(7) A, β = 114.606(3)°, while for the 2b-phase at 150 K, a = 15.5206(4) A, b = 7.6958(2) A, c = 15.7137(3) A, β = 92.580(7)°. The C - N bond length in the β-form at 150 K of 1.335(3) A indicates considerable double bond character: the rotational barrier of the C - N bond in CDCl3 was calculated to be 52.4 kJ mol-1.
- Aupers, John H.,Skakle, Janet M.S.,Wardell, James L.,Wardell, Solange M.S.V.
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Read Online
- Using Solid Catalysts in Disulfide-Based Dynamic Combinatorial Solution- and Mechanochemistry
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It was shown for the first time that solid amines can act as catalysts for disulfide-based dynamic combinatorial chemistry (DCC) by ball mill grinding. The mechanochemical equilibrium for the two disulfide reactions studied was reached within 1–3 h using ten different amine catalysts. This contrasts with the weeks to months to achieve solution equilibrium for most solid amine catalysts at 2 %mol mol?1 concentration in a 2 mMolar disulfide dynamic combinatorial library in a suitable solvent. The final mechanochemical equilibrium was independent of the catalyst used but varied with other ball mill grinding factors such as the presence of traces of solvent. The different efficiencies of the amines tested were discussed.
- Belenguer, Ana M.,Lampronti, Giulio I.,Michalchuk, Adam A. L.,Sanders, Jeremy K. M.
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- Palladium-Catalyzed Picolinamide-Directed Benzylic C(sp3)?H Chalcogenation with Diaryl Disulfides and Diphenyl Diselenide
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The first palladium-catalyzed direct benzylic C(sp3)?H chalcogenation with diaryl disulfides and diphenyl diselenide has been established. The coupling reaction proceeds between the thioether radical and palladiumcycle intermediate. Picolinamide serves as an excellent directing group for the C?H activation of benzylic C(sp3)?H and can be easily removed. The current protocol exhibits a relatively broad substrate scope and high functional group compatibility. A mechanistic study indicates that palladium(IV) intermediate is probably formed during the course of the reaction. (Figure presented.).
- Wang, Kai,Hou, Jiahao,Zhang, Changjun,Cheng, Ke,Bai, Renren,Xie, Yuanyuan
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supporting information
p. 2947 - 2952
(2020/06/17)
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- Biocatalytic synthesis of diaryl disulphides and their bio-evaluation as potent inhibitors of drug-resistant Staphylococcus aureus
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Staphylococcus aureus is a WHO Priority II pathogen for its capability to cause acute to chronic infections and to resist antibiotics, thus severely impacting healthcare systems worldwide. In this context, it is urgently desired to discover novel molecules to thwart the continuing emergence of antimicrobial resistance. Disulphide containing small molecules has gained prominence as antibacterials. As their conventional synthesis requires tedious synthetic procedure and sometimes toxic reagents, a green and environmentally benign protocol for their synthesis has been developed through which a series of molecules were obtained and evaluated for antibacterial activity against ESKAPE pathogen panel. The hit compound was tested for cytotoxicity against Vero cells to determine its selectivity index and time-kill kinetics was determined. The activity of hit was determined against a panel of S. aureus multi-drug resistant clinical isolates. Also, its ability to synergize with FDA approved drugs was tested as was its ability to reduce biofilm. We identified bis(2-bromophenyl) disulphide (2t) as possessing equipotent antimicrobial activity against S. aureus including MRSA and VRSA strains. Further, 2t exhibited a selectivity index of 25 with concentration-dependent bactericidal activity, synergized with all drugs tested and significantly reduced preformed biofilm. Taken together, 2t exhibits all properties to be positioned as novel scaffold for anti-staphylococcal therapy.
- Saima,Soni, Isha,Lavekar, Aditya G.,Shukla, Manjulika,Equbal, Danish,Sinha, Arun K.,Chopra, Sidharth
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p. 171 - 178
(2019/01/04)
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- Synthesis and nano-Pd catalyzed chemoselective oxidation of symmetrical and unsymmetrical sulfides
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A highly chemoselective, efficient and nano-Pd catalyzed protocol for the rapid construction of sulfoxides and sulfones via the oxidation of symmetrical and unsymmetrical sulfides using H2O2 as an oxidant has been developed, respectively. The ready availability of starting materials, easy recovery and reutilization of the catalyst, wide substrate scope, and high yields make this protocol an attractive alternative. The process also involves the metal-free and microwave-promoted synthesis of symmetrical diarylsulfides, and FeCl3-mediated preparation of symmetrical diaryldisulfides through the reaction of arenediazonium tetrafluoroborates with Na2S·9H2O as a sulfur source. In addition, unsymmetrical sulfides were generated via the K2CO3-mediated reaction of arenediazonium tetrafluoroborates with symmetrical disulfides.
- Li, Xing,Du, Jia,Zhang, Yongli,Chang, Honghong,Gao, Wenchao,Wei, Wenlong
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p. 3048 - 3055
(2019/03/21)
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- Orthanilic acid synthesizing method
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The invention discloses an orthanilic acid synthesizing method. The method includes steps: step one, taking water as a reaction medium, mixing ortho-nitrochlorobenzene and sodium disulfide solution, and stirring at 60-90 DEG C until reaction is finished, so that bis(dinitrophenyl)disulfide is obtained; step two, taking water as a reaction medium, adding the bis(dinitrophenyl)disulfide while addingan oxidant into a reaction system, stirring at 60-90 DEG C until reaction is finished, so that aqueous solution of o-nitrobenzenesulphonic acid is obtained; step three, taking water as a reaction medium and o-nitrobenzenesulphonic acid as a reaction substrate, adding or not adding auxiliary agents, adding catalysts under conditions of 90-120 DEG C and 0.8-2.0MPa, stirring until reaction is finished, and acidizing to obtain orthanilic acid. The orthanilic acid yield of the method reaches 90% or above and increased by 20% or above as compared with that of an old process, product purity is higher than 99.5%, and great crystal form and freeness of metal ion residues are realized. The method has advantages of high economic benefits, environmental friendliness and the like.
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Paragraph 0053; 0054; 0065; 0075; 0096; 0107
(2018/03/25)
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- A novel dual-nano assisted synthesis of symmetrical disulfides from aryl/alkyl halides
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Here, we have reported a novel approach towards dual-nano assisted synthesis of disulfides from coupling of alkyl/aryl halides and sulfur nanoparticles. The indium oxide nanoparticles as catalyst expedite the conversion and sulfur nanoparticle notably enhances the miscibility, providing a faster, high yielding and cost-effective process in ethanol-water system. The method has synthetic advantages in terms of mild reaction framework, catalyst regeneration, and absence of any sulfide or polysulfide linkage as by-product leading to a column free synthesis. A variety of alkyl, aryl and heteroaryl symmetrical disulfides are obtained in good to excellent yields up to exceeding 98%.
- Devi, Namita,Hazarika, Sukanya,Gogoi, Prasanta,Barman, Pranjit
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supporting information
p. 1927 - 1938
(2018/07/21)
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- Syntheses, biological activities and SAR studies of novel carboxamide compounds containing piperazine and arylsulfonyl moieties
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A series of novel carboxamide compounds 19a-19j, 20a-20j and 22a-22d containing piperazine and arylsulfonyl moieties have been synthesized. The bioassay results showed that some compounds exhibited favorable herbicidal activities against dicotyledonous plants and many of them possessed excellent antifungal activities. Among 24 novel compounds, some showed superiority over the commercial fungicides Chlorothalonil, Dimethomorph, Thiophanate-methyl, Iprodione, and Zhongshengmycin at 500 mg/L concentration. Some compounds also exhibited high KARI inhibitory activity at 100 γ1/4g/mL concentration and could be used as new KARI lead inhibitors for further studies. Moreover, SAR of these new compounds were comprehensively investigated using different computational methods in which 3D-QSAR model obtained provided useful information for further structural optimization for the discovery of new fungicides. The results of this research will contribute to explore comprehensive biological activities of piperazine-containing compounds in different areas of chemistry.
- Wang, Bao-Lei,Shi, Yan-Xia,Zhang, Shu-Jun,Ma, Yi,Wang, Hong-Xue,Zhang, Li-Yuan,Wei, Wei,Liu, Xing-Hai,Li, Yong-Hong,Li, Zheng-Ming,Li, Bao-Ju
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p. 167 - 178
(2016/04/26)
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- Bovine serum albumin triggered waste-free aerobic oxidative coupling of thiols into disulphides on water: An extended synthesis of bioactive dithiobis(phenylene)bis(benzylideneimine) via sequential oxidative coupling-condensation reactions in one pot from aminothiophenol and benzaldehyde
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Bovine serum albumin (BSA) has been explored for aerobic oxidative coupling of thiols (aromatic, heterocyclic as well as aliphatic) "on water" towards formation of disulphides (SS) without using any metal/non-metal complexes, bases and additives, which renders the process environmentally benign and economically attractive with good recyclability (up to four cycles). The developed green protocol was further extended for synthesis of diallyldisulphide (DADS), an important constituent of natural occurring allicin. Among various synthesized disulphides, bis(2-aminophenyl)disulphide, obtained by oxidative coupling of 2-aminothiophenol in BSA, was further utilized for condensation with benzaldehyde in the same pot thus enabling easy access to bioactive dithiobis(phenylene)bis(benzyldeneimine). This is the first example of BSA catalysed sequential (oxidation/condensation) reaction where one SS and two CN bonds are formed solely "on water."
- Saima,Lavekar, Aditya G.,Kumar, Rajesh,Sinha, Arun K.
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p. 113 - 123
(2015/04/14)
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- Divergent synthesis and tuning of the electronic structures of cobalt-dithiolene-fullerene complexes for organic solar cells
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A pentakis(aryl)[60]fullerene cobalt trisulfide complex (1a) was obtained from the reaction of a pentakis(aryl)[60]fullerene cobalt dicarbonyl complex (2a) with triphenylmethanethiol. This reaction proceeded smoothly even at ambient temperature to produce 1a in moderate to high yield. The series of pentakis(aryl)[60]fullerene cobalt dithiolene complexes 3-9 were also synthesized by the reaction of 1a with a variety of readily available disulfide compounds. The HOMO and LUMO levels of the complexes could be tuned by making changes to the substituents on the dithiolene ligands, with changes to the electronic structure of the compounds influencing their photovoltaic performance, especially in terms of their open-circuit voltage. Small-molecule organic solar cells constructed from the naphthalene dithiolene complex 9 and tetrabenzoporphyrin showed a power conversion efficiency of 0.59%.
- Matsuo, Yutaka,Ogumi, Keisuke,Maruyama, Masashi,Nakagawa, Takafumi
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p. 659 - 664
(2014/03/21)
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- Synthesis of disulfides and diselenides by copper-catalyzed coupling reactions in water
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A simple and efficient protocol for copper-catalyzed coupling reactions between aryl halides and elemental sulfur or selenium has been developed. A variety of disulfides and diselenides can be obtained in moderate to excellent yields up to 96%. The Royal Society of Chemistry 2013.
- Li, Zhengkai,Ke, Fang,Deng, Hang,Xu, Hualong,Xiang, Haifeng,Zhou, Xiangge
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supporting information
p. 2943 - 2946
(2013/07/25)
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- Synthesis of diaryl disulfides via the reductive coupling of arylsulfonyl chlorides
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A facile synthesis of diaryl disulfides from arylsulfonyl chlorides in the presence of triphenylphosphine has been developed.
- Kabalka, George W.,Reddy, Marepally Srinivasa,Yao, Min-Liang
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scheme or table
p. 7340 - 7342
(2010/03/01)
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- Synthesis of α,β-unsaturated Pseudogeminal [2.2]paracyclophane bisketones
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An unexpected synthesis of α,β-unsaturated pseudogeminal [2.2]paracyclophane bisketones has been realized via a dyotropic-type rearrangement of the corresponding bisallenyl o-nitrophenyl sulfoxides. Georg Thieme Verlag Stuttgart.
- Birsa, M. Lucian,Hopf, Henning
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p. 2753 - 2755
(2008/02/12)
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- Mild and highly efficient preparation of symmetrical disulfides and diselenides using bipyridinum hydrobromide perbromide as a new oxidative reagent
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A rapid and efficient method for the large-scale synthesis of symmetrical disulfides and diselenides is developed involving oxidative coupling of corresponding thiols and selenols using bipyridinium hydrobromide perbromide (BPHP). Copyright Taylor & Francis Inc.
- Joshaghani,Khosropour,Jafary,Mohammadpoor-Baltork
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p. 117 - 123
(2007/10/03)
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- Imination of sulfur-containing compounds: XXXV. New preparation method and oxidative benzenesulfonylimination of unsymmetrical disulfides
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A new preparative method of synthesis was developed for unsymmetrical and symmetrical disulfides. This method involves sulfenylation of sodium thiolates with N-arenesulfenyl-N,N′-bis(arenesulfonyl)sulfinamidines. Imination of unsymmetrical disulfides with sodium chloroamides of sulfonic acids occurs at the more nucleophilic sulfur atom, affording N,N′ -bis(arenesulfonyl)sulfinamidines and symmetrical disulfides.
- Koval'
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p. 232 - 234
(2007/10/03)
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- Radical-nucleophilic substitution (SRN1) reactions. Part 7. Reactions of aliphatic α-substituted nitro compounds
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α-Nitrothiocyanates R2C(SCN)NO2 have been prepared by oxidative addition of thiocyanate anion to nitronate anions and undergo SRN1 substitution reactions by loss of thiocyanate with nitronate anions, phenylsulfinate, azide and p-nitro- and p-chloro-benzenethiolates in dipolar aprotic solvents. 2-Nitro-2-thiocyanatopropane and other 2-substituted-2-nitropropanes [Me2C(X)NO2 with X = I, Br, Cl, NO2, PhSO2] react with thiolates by SRN1 reactions and/or redox reactions to give disulfides by a polar abstraction or chain SET (SET2) mechanisms. The products are dependent on the nucleophilicity of the thiolates, the polarisability of the α-substituent, the solvent and the presence of light catalysis, radical traps or strong electron acceptors. 2-Substituted-2-nitropropanes [Me2C(X)NO2 with X = N3, NO2, CN, p-NO2-C6H4-N=N] undergo SRN1 substitutions with thiolates by loss of nitrite. 2-Substituted-2-nitropropanes Me2C(X)NO2 and thiolates only yield disulfides in methanol due to solvation of the nitro groups.
- Al-Khalil,Bowman,Gaitonde,Marley,Richardson
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p. 1557 - 1565
(2007/10/03)
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- Conformational preferences and supramolecular aggregation in 2-nitrophenylthiolates: Disulfides and thiosulfonates
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In each of the asymmetrically substituted disulfides 2-nitro-4′-methyldiphenyl disulfide, C13H11NO2S2 (1), 2-nitro-4′-chlorodiphenyl disulfide, C12H8ClNO2S2 (2), 2,4-dinitro-4′-methyldiphenyl disulfide, C13H10N2O4S2 (3), and 2,4-dinitrophenyl-2′-methoxycarbonylmethyl disulfide, C9H8N2O6S2 (4), and in both of the symmetrically substituted disulfides bis(2-nitrophenyl) disulfide, C12H8N2O4S2 (5), and bis(2-nitro-4-trifluoromethylphenyl) disulfide, C14H6F6N2O4S2 (6), the 2-nitro groups are essentially coplanar with the adjacent aryl ring and the S atom remote from the nitrated aryl ring is also essentially coplanar and transoid to the nitro group. In S-(2-nitrophenyl) 2-nitrobenzene thiosulfonate, C12H8N2O6S2 (7), which contains three independent molecules in the asymmetric unit, all six of the independent nitro groups are twisted out of the plane of the adjacent aryl rings. The crystal structures of (1)-(3) contain isolated molecules, that of (4) contains centrosymmetric dimers held together by C-H...O hydrogen bonds, while in the structures of (5)-(7), respectively, the C-H...O hydrogen bonds generate one-, two-and three-dimensional arrays. The interplay between molecular conformation and supramolecular aggregation is discussed.
- Glidewell, Christopher,Low, John N.,Wardell, James L.
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p. 893 - 905
(2007/10/03)
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- Oxidation in fluoro alcohols: Mild and efficient preparation of disulfides from thiols
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Quantitative oxidative conversion of thiols to disulfides was effected by aqueous 30% H2O2 in trifluoroethanol at ambient temperature under neutral conditions.
- Kesavan, Venkitasamy,Bonnet-Delpon, Daniele,Begue, Jean-Pierre
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p. 223 - 225
(2007/10/03)
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- S-aryl N,N-dialkylamidothiosulfates, a novel class of sulfenic acid derivatives
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A method for the synthesis of S-aryl N,N-dialkylamidothiosulfates, a novel class of sulfenic acid derivatives, was proposed. The method is based on the reaction of arenesulfenyl chlorides with N,N-dialkylamidosulfinic acids or with secondary amines in liquid SO2 in the presence of triethylamine. In the presence of halogen-containing Lewis acids, 5-aryl N,N-dialkylamidothiosulfates add to the C=C bonds to give aryl β-haloalkyl sulfides.
- Zyk,Beloglazkina,Lapshina,Belova
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p. 1478 - 1480
(2007/10/03)
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- 1-Benzyl-1-aza-4-azoniabicyclooctane periodate as new oxidant for oxidation of thiols and sulfides to the corresponding disulfides and sulfoxides under anhydrous conditions
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1-Benzyl-1-aza-4-azoniabicyclooctane periodate (BAABCOP) 1, readily prepared as an orange solid from commercially available DABCO (1,4-diazobicyclooctane) performs oxidation in anhydrous conditions. Under these conditions, thiols are selectively oxidised to disulfides. Sulfides are also oxidised to the corresponding sulfoxides under these conditions.
- Hajipour, A. R.,Mahboubghah, N.
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p. 1041 - 1043
(2007/10/03)
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- Reactions of arensulfenamides with olefins in the presence of picric acid
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N-(2-and 4-Nitrophenylthio)morpholines in the presence of equimolar amounts of picric acid enter into the reaction of electrophilic sulfenylation of the C=C norbornene bond to give bi-and tricyclic sulfides. With cyclohexene, trans-2-arylthiocyclohexanol are formed.
- Zyk,Beloglazkina,Mamaeva
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p. 1617 - 1619
(2007/10/03)
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- Process for preparing 2,2'-dinitrodiphenyl disulphide
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2,2'-Dinitrodiphenyl disulphide is obtained in particularly good yields and purities in a simple manner by reacting 2-chloronitrobenzene with an aqueous alkali metal disulphide solution in the presence of phase transfer catalysts and an organic solvent.
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- Pathways and Stereochemistry of Rearrangements in Reactions of Sulfenyl Chlorides with Alkenes
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In reactions of 3,3-dimethyl-1-butene and 3-methyl-1-butene with 2,4-dinitrobenzenesulfenyl chloride in the systems M(ClO4)n-CH3NO2 (M=Li or Mg), 1,2 shifts of the methyl group and hydride ion respectively occur directly within the AdE process (? pathway of the rearrangement).In the same systems reactions of these alkenes with arenesulfenyl chlorides containing in the electrophilic moiety less electronegative substituents, as compared to the dinitrophenyl group, initially yield β-chloro sulfides, which under reaction conditions mostly undergo rearrangements (? pathway of the rearrangement).In nitromethane in the presence of LiClO4, AlCl3, or AgBF4 erythro-2-arylthio-1-chloro-1-deutero-2,3-dimethylbutanes are converted into stereoisomeric thiochromans; their ratio is controlled by the nature of the metal compound added, electronic properties of substituents in the arylthio moiety, and reaction temperature.
- Borisov, A. V.,Bodrikov, I. V.,Borisova, G. N.,Smit, V. A.,Lutsenko, A. I.,Bel'skii, V. K.
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p. 943 - 951
(2007/10/03)
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- OXIDATIVE IMIDATION OF N-ARYLSULFONYLARENESULFENAMIDES. N-IMIDES
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The reaction of the sodium salts of N-arylsulfonylarenesulfenamides with N-halogenoimides and also with chlorine in the presence of the imides gave N-imides. Their spectral characteristics and biological activity were studied.
- Koval', I. V.,Oleinik, T. G.,Timoshin, M. Yu.
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p. 418 - 421
(2007/10/02)
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- Synthesis and Acylation of Salts of L-Threonine β-Lactone: A Route to β-Lactone Antibiotics
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The synthesis and N-acylation of β-lactones derived from L-threonine and L-allo-threonine were investigated.Treatment of N--L-allo-threonine (7b) with 4-bromobenzenesulfonyl chloride in pyridine at -43 to 0 deg C gives the corresponding β-lactones 8a and 8b, respectively, in 45-56 percent yields.These can be deprotected with thiophenol or p-thiocresol in the presence of p-toluenesulfonic acid to produce optically pure salts of L-threonine β-lactone (9a) and its allo isomer 9b (65-92percent).Compound 9a is readily acylated by reagents such as acid chlorides (e.g., acetyl, benzoyl) and mixed anhydrides to afford N-acyl β-substituted β-lactones such as 10 (antibiotic SQ 26,517), 14, 15, and 16 in good yield (84-92percent).Reaction of β-lactones 8a, 8b, and 9a with HBr in acetic acid results in nucleophilic ring opening by bromide at the β-position to give pure isomers of 2-amino-3-bromobutanoic acid.
- Pu, Yunlong,Martin, Fionna M.,Vederas, John C.
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p. 1280 - 1283
(2007/10/02)
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- REACTIONS OF N,N-BIS(TRIMETHYLSILYL)ARENESULFENAMIDES AND OF N,N,N',N'-TETRAKIS(TRIMETHYLSILYL)-BENZENEDISULFENAMIDES WITH SELENIUM TETRACHLORIDE
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The reactions of o-nitro- and p-nitro-N,N-bis(trimethylsilyl)benzenesulfenamides with SeCl4 lead to elementary selenium and nitrogen and the corresponding diaryl disulfides.The product of the reaction of SeCl4 with N,N,N',N'-tetrakis(trimethylsilyl)-o-benzenedisulfenamide is 1,3,2-benzodithiazolium chloride.
- Zibarev, A. V.,Rogoza, A. V.,Konchenko, S. N.,Fedotov, M. A.,Furin, G. G.
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p. 401 - 404
(2007/10/02)
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- Formation of Stable Aryldisulphide Ions in Dimethylacetamide from the Reaction of Sulphur with Thiolate Ions
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The conditions for the formation of aryldisulphide ions, RS2- during the direct reaction of sulphur with thiolate ions RS- have been studied by the use of spectroelectrochemistry in dimethylacetamide.The series of derivatives examined was R = p-tolyl (1), phenyl (2), 8-quinolyl (3), 2- and 4-pyridyl (4), (5), N-oxido 4-pyridyl (6), 2- and 4-nitrophenyl (7), (8), and 2-(5-nitropyridyl) (9).Sulphur reaction leads to RS2- ions and preceded the oxidation to diaryldisulphide RS2R and polysulphide ions Sx-.With derivatives (1)-(3), both reactions are successive and practically stoicheiometric, while for derivatives containing electron-withdrawing groups (6)-(9), the equilibrium constants have been measured.Analysis of the reaction products by methylation of several solutions of thiolate ions in the presence of sulphur confirmed the possibility of obtaining aryldisulphide ions stabilized in aprotic dipolar media.
- Benaichouche, Meriem,Bosser, Gerard,Paris, Jacky,Auger, Jacques,Plichon, Vincent
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- Conversion of o-Nitrothiophenols into o-Aminobenzenesulphonic Acids
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The mechanism of conversion of o-nitrothiophenols into o-aminobenzenesulphonic acids in aqueous dioxane has been investigated with particular reference to evidence for the rate-determining formation of a cyclic intermediate.This intermediate is susceptible to interception by both external and internal nucleophilic functions, and the sulphonic acid is shown by isotope labelling experiments to take two oxygen atoms from H2(18)O in the reaction mixture, under conditons in which neither starting materials nor products exchange with H2(18)O.A tentative pathway is advanced.
- Bamfield, Peter,Greenwood, David,Lotey, Harvinder,Stirling, Charles J. M.
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p. 691 - 696
(2007/10/02)
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- Bromonitromethane. A Versatile Electrophile
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Pathways in reactions of bromonitromethane with a variety of nucleophiles have been investigated.With thiolates, the electrophilic centre is bromine and the initial products are disulphides.When the thiolate ion itself carries an electrophilic centre such as carbonyl or cyano β-to sulphur, the product is a nitrothiophene derived from subsequent reaction of the first-formed disulphide with nitronate ion displaced in the initial process.This provides a generalisation of earlier nitrothiophene synthesis by this route.In reactions with arenesulphinate ion, the electrophilic centre is also bromine and equilibration between the initial reactants and the initial products, sulphonyl bromide and nitronate ion, is established.The components of the equilibrium subsequently react either with each other or with the solvent.Reactions with sulphides are slow and distal substituents such as hydroxy- or cyano- so much reduce reactivity that no reaction is observed.Dimethyl sulfide attacks bromonitromethane at the carbon atom,and subsequent attack on the nitromethyl sulphonium salt initially formed gives methylthionitromethane and trimethylsulphonium bromide.Iodide ion attacks at bromine to give iodine, presumably via iodine bromide, but with tervalent phosphorus nucleophiles, attack is at oxygen giving the corresponding oxides and HCN in a double deoxygenation sequence.For hydroxide, methoxide and hydride ions (from sodium borohydride), nucleophilic attack is at hydrogen and the nitronate ion produced is inert to further attack.There is no evidence of carbene formation by α-elimination.When the anion of bromonitromethane is allowed to react with tributylboron, the anionic migration-displacement which follows boron-carbon bond formation, yields 1-nitropentane.The anion of bromonitromethane is unreactive towards aldehydes and electrophilic alkenes.
- Fishwick, Brian R.,Rowles, David K.,Stirling, Charles J. M.
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p. 1171 - 1180
(2007/10/02)
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- Chemistry of Sulfenic Acids. 7. Reason for the High Reactivity of Sulfenic Acids. Stabilization by Intramolecular Hydrogen Bonding and Electronegativity Effects
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It is proposed that the reason sulfenic acids (RSOH) are so reactive and usually not isolated or even detected is that they form thiosulfinates (RS(O)SR) so readily.This is a consequence of the sulfenic acid hydrogen-bonded dimer, 1, which lowers the energy of activation for thiosulfinate formation.The stability of the few sulfenic acids that have been isolated can be explained in terms of steric, electronic, and intramolecular hydrogen-bonding effects which prevent dimer formation.The importance of these effects on the stability of simple unstable sulfenic acids was demonstrated by flash vacuum pyrolysis (FVP) and the thiosulfinate/vinyl sulfoxide ratio.A novel, high yield, rearrangement of sulfenic acid 19f to 1,3-benzothiazine 26 was observed.
- Davis, Franklin A.,Jenkins, Linda A.,Billmers, Robert L.
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p. 1033 - 1040
(2007/10/02)
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- SH2 REACTIONS OF SLENOSULFIDES WITH CARBON RADICALS
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o-Nitrophenyl phenylselenyl sulfide suffered SH2 attack by carbon radicals on selenium atom to give selenide and thiyl radical; the realtive rate constant of the selenosulfide with phenyl radical was compared with those of the other selenium compounds.
- Yoshida, Masato,Cho, Toshitsura,Kobayashi, Michio
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p. 1109 - 1112
(2007/10/02)
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- Reaction of 3-Phenylglycidic Esters. Part 1. Stereoselective Opening of the Oxirane Ring of trans-3-Phenylglycidic Esters with 2-nitrothiophenols and the Effects of Various Catalysts Thereon
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In the reaction of 2-nitrothiophenol (2) with trans-3-phenylglycidic esters carrying various substituents on the benzene ring, both reactivity and stereoselectivity of the oxirane ring-opening of the glycidates were markedly influenced by the electronic nature of the substituents.The presence of electron-donating groups was favourable for both reactivity and the preferential formation of cis-opening products, while the reverse was true for electron-withdrawing groups.As a result of our investigation on the catalytic effect of various Lewis acids in the reaction of the 4-methoxy derivative (1) with (2), tin compounds were found to be effective catalysts for cis-opening and readily produced the threo-nitro ester (3a), a key intermediate for the synthesis of diltiazem (5).Isolation of the crystalline complex (adduct A) from the reaction of (2) with SnCl4 and its efficient catalytic activity similar to that of SnCl4 suggest that the transition state involves co-ordination of tin derivatives both with (2) and the epoxy oxygen of (1) to cause highly specific cis-opening.
- Hashiyama, Tomiki,Inoue, Hirozumi,Konda, Mikihiko,Takeda, Mikio
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p. 1725 - 1732
(2007/10/02)
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- Benzenesulphenanilidyl Radicals. Part 2. Substituent and Solvent Effects on the Reactivity of 4'-Substituted Benzenesulphenanilidyl Radicals Produced by Oxidation with Lead Dioxide of the Corresponding Benzenesulphenanilides
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Oxidation of benzenesulphenanilide (1d) with lead dioxide in benzene affords the p-benzoquinone diimine (5d) together with minor amounts of N,N-bis(phenylthio)aniline (4d) and diphenyl disulphide (7a).The formation of the products is explained in terms of p-C-N coupling of the benzenesulphenanilidyl radicals (2d) and subsequent fragmentation of the resulting dimer.A similar trend is observed in the oxidation of 4'-chloro- and 4'-bromo-benzenesulphenanilides (1e) and (1f), whereas 4'-nitrobenzenesulphenanilide (1g) leads to the o-phenylenediamine (12g), arising from o-C-N coupling of the sulphenanilidyl radical (2g).The oxidation of the sulphenanilides (1e) and (1f) in acetonitrile produces the phenazines (3e) and (3f) and the disulphide (7a), whereas the anilide (1g) and 4'-cyanobenzenesulphenanilide (1h) give azobenzenes (11g) and (11h) and the disulphide (7a); these results are discussed in terms of a possible mechanism involving oxidation of the N-N dimers (14e-h) which are in rapid equilibrium with the corresponding sulphenanilidyl radicals (2e-h).Evidence is also presented that the oxidation of 2-nitrobenzenesulphenanilides leads to products ascribable to intermediate 2-nitrobenzenesulphenanilidyl radicals, in contrast with a previous claim.
- Balboni, Claudio,Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
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p. 2111 - 2117
(2007/10/02)
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- Studies on Sulfenamides. VII. Anodic Oxidation of 3'- and 2'-Substituted 2-Nitrobenzenesulfenanilides
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Controlled potential electrolysis of 2'-(p-chlorophenyl)amino-4'-chloro-2-nitrobenzenesulfenanilide (4c) gave 2,7-dichlorophenazine in good yield.This result suggested that in the electrolysis of 4'-substituted 2-nitrobenzenesulfenanilides the ring closure to form the 2,7-disubstituted phenazines takes place through the binding of the nitrenium ion (B) to the 2'-position of the sulfenanilides.As for the 3'- and 2'-substituted 2-nitrobenzenesulfenanilides, most of the nitrenium ions bind to the 4'-position and are oxidized further to the p-quinonediimine derivatives, and most of these are oxidized further to unidentified resinous compounds.Keywords: anodic oxidation; 2-nitrobenzenesulfenanilides; 2,7-disubstituted phenazines; oxidation of sulfenamides; nitrenium ion; benzoquinonediimines
- Sayo, Hiroteru,Mori, Koichi,Michida, Takashi
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p. 3782 - 3785
(2007/10/02)
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- SULPHUR SUBSTITUTED ORGANOTIN COMPOUNDS. PART 6. REACTIONS OF MERCAPTOMETHYLTIN COMPOUNDS WITH ARENESULPHENYL CHLORIDES
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Reactions between Ph3SnCH2Ar and 2-NO2C6H4SCl lead to the formation of 2-(ArSCH2)-6NO2C6H3SSC6H4NO2-2 via the sigmatropic rearrangement of the S-arylthiosulphonium ylides CH2(1-)-S(1+)(Ar)SC6H4NO2-2.
- Wardell, James L.,Taylor, Robin D.
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p. 1735 - 1736
(2007/10/02)
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- Benzenesulphenanilidyl Radicals. Reactivity of 4'-Methoxy- and 4'-Methoxy-2-nitro-benzenesulphenanilidyl Radicals
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Oxidation of 4'-methoxybenzenesulphenanilide (1a) with lead dioxide at 30 deg C afforded the NN-bis(phenylthio)-p-anisidine (7a) and 2,7-dimethoxypheazine (3a) together with minor amounts of diphenyl (4a), whereas at 10 deg C almost exclusive formation of compound (7a) and the o-benzoquinone di-imine (8a) was observed; compound (8a) was found to be thermally unstable and to give, quantitatively, compounds (4a) and (3a).The reaction products are rationalized by assuming that 4'-methoxybenzenesulphenanilidyl radicals (2a), produced by oxidation of compound (1a), undergo Cortho-N coupling to give the dimer (9a), which is responsible for the reaction products observed.A comparable trend was observed by producing the radical (2a) from reaction of compound (1a) with t-butoxy-radicals and by thermal decomposition of compound (7a).These findings rule out the nitrene mechanism previously suggested for the formation of compound (3) from oxidation of the reagent (1a).Evidence has been found that Cortho-N coupling is the main reaction path, exhibited also by 4'-methoxy-2-nitrobenzenesulphenanilidyl radicals (2c) generated from the corresponding anilide (1c) by reaction with t-butoxy-radicals or oxidation with lead dioxide, which thus rejects a previous claim that the radicals (2) (Ar = Ph and Ar = C6H4NO2-o) exhibit different chemical behaviour.
- Benati, Luisa,Montevecchi, P. Carlo,Spagnolo, Piero
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p. 3049 - 3054
(2007/10/02)
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- In Search of New Sulfur Transfer Agents
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The chemistry of various sulfur-transfer agents is studied.The reaction of aromatic sulfenyl chloride 5 in the presence of imidazole and/or triethylamine gives the aryl disulfides 7 in 14-85 percent yield, whereas in the case of the corresponding benzylsulfenyl chlorides 9 in the presence of triethylamine and/or caprolactam, both disulfide 10 and benzyl chlorides 11 are formed in 0-81 precent and 10-72 precent yield, respectively. - The transfer reactions of 3-sulfenylated hydantoins 18 with amines are useful for the preparation of the unsymmetric sulfenamides 20 in 31 -61 percent yield.Analogous transfer reactions of compounds 23 and 24 with piperidine give N,N'-thiodipiperidine (3, X = CH2) in 71-80 percent.
- Sosnovsky, George,Krogh, James A.
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p. 121 - 136
(2007/10/02)
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- STUDIES ON SULFENAMIDES. VI. CYCLIC VOLTAMMETRY AND CONTROLLED POTENTIAL ELECTROLYSIS OF 4'-SUBSTITUTED 2-NITROBENZENESULFENANILIDES IN THE PRESENCE OF TRIFLUOROACETIC ACID OR PYRIDINE
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Anodic oxidation of 4'-substituted 2-nitrobenzenesulfenanilides (4'-OMe (1a), 4'-Me (1b), 4'-H (1c), 4'-Cl (1d), 4'-COOEt (1e), 4'-COCH3 (1f), 4'-NO2 (1g) and 4'-ethoxycarbonyl-N-methyl-2-nitrobenzenesulfenanilide (1h) was investigated by cyclic voltammetry and controlled potential electrolysis at a glassy-carbon or a reticulated vitreous carbon anode in acetonitrile containing 1 percent trifluoroacetic acid (TFA) or 1 percent pyridine.The peak potentials of 1a-g in acetonitrile containing TFA were 0.23-0.55 V more positive than those in acetonitrile containing pyridine.On the other hand, the peak potential of 1h was not affected by addition of TFA or pyridine.This suggests that 1a-g partially dissociate into the sulfenamide anions in the presence of pyridine.Electrolysis of 1a, 1b, and 1d in the presence of TFA gave the corresponding 2,7-disubstituted phenazines in higher yields than that in the absence of TFA.Electrolysis of 1a-d the presence of pyridine gave the corresponding pyridinated sulfenanilides, and that of 1e and 1f gave the corresponding 4,4'-disubstituted azobenzenes.Electrolysis of 1g gave p-nitroaniline both in the absence and presence of pyridine.The variation of yields of the phenazines and species of the products was explained in terms of the extent of dissociation of the dication intermediate, which in turn depends on the 4'-substituent.The nitrenium ions and nitrines are suggested to be intermediates in the formation of the corresponding phenazines and the primary amines, respectively.The azobenzenes are considered to be oxidation products of the primary amines, respectively.The azobenzenes are considered to be oxidation products of the primary amines.Keywords: - anodic oxidation; cyclic voltammetry; 2-nitrobenzenesulfenanilides; 2,7-disubstituted phenazines; oxidation of sulfenamides; nitrenium ion; nitrine; RVC; N-arylpyridinium perchlorate
- Sayo, Hiroteru,Mori, Koichi,Michida, Takashi
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p. 2598 - 2603
(2007/10/02)
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- REACTIONS OF THIOLATE ANIONS WITH 2-SUBSTITUTED-2-NITROPROPANES
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Thiolates undergo substitution reactions with 2-substituted-2-nitropropanes by an SRN1 mechanism or are oxidised to disulphides by an ionic mechanism.
- Bowman, W. Russel,Richardson, Geoffrey D.
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p. 1551 - 1554
(2007/10/02)
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- Intermolecular Trapping of Sulphenylnitrenes by Alkenes
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Oxidation of 2,4-dinitrobenzenesulphenamide with lead tetra-acetate in the presence of electron-rich alkenes (styrene, (E)- and (Z)-1-phenylpropene, 2-phenylpropene, (Z)-but-2-ene, and butadiene) gives the corresponding substituted N-(2,4-dinitrophenylsulphenyl))aziridines.Intermolecular trapping of a presumed sulphenylnitrene intermediate is also successful in the oxidation of 2-nitrobenzenesulphenamide but fails for RSNH2 when R = PhCO, 4-ClC6H4, or 4-NO2C6H4.
- Atkinson, Robert S.,Judkins, Brian D.
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p. 2615 - 2619
(2007/10/02)
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