- Cyanoacetylene and its derivatives: XXVIII. Reactions of 2-mercaptobenzothiazole with nitriles of α,β-acetylene γ-hydroxyacids and with 3-phenyl-2-propynonitrile
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Nucleophilic addition of 2-mercaptobenzothiazole to 4-alkyl-4-hydroxy-2-alkynonitriles at 1:1 ratio in the presence of 4-6 wt% of Et3N occurs regio-and stereospecifically to afford (Z)-4-alkyl-3-(benzothiazolyl-2-thio)-4-hydroxy-2-alkenonitriles (yield 40-51%). In the presence of 1.3 wt% of Dabco the thiazole and 4-hydroxy-4-methyl-2-pentynonitrile (1:1) give rise to a mixture of 2-alkenonitrile and 2-(3,3,6,6-tetramethyl-2-cyanomethyl-5-cyanomethylene-1,4-oxathian-2-yl)thiobenzothiazole. At the use of 4-6 wt% of LiOH arises an intractable mixture containing 1,4-oxathiane, benzothiazol-2-one, 2-[1-(5,5-dimethyl-2-cyanomethyl)-4-cyanomethylene-1,3-oxathiolan-2-yl)-1-methylethyl]thiobenzothiazole. bis(2,2,5,5-tetramethyl-6-cyanomethyl-3-cyanomethylene-1,4-oxathian-6-yl) disulfide, bis[1-(5,5-dimethyl-2-cyanomethyl-4-cyanomethylene-1,3-oxathiolan-2-yl)-1-methylethyl] disulfide, and 3-[1-(5,5-dimethyl-2-cyanomethyl-4-cyanomethylene-1,3-oxathiolan-2-yl)-1-methylethyl]benzothiazol-2-one (according to 1H and 13C NMR data). 2-mercaptobenzothiazole adds to 3-phenyl-2-propynonitrile in the presence of 7 wt% of KOH with regio-and stereospecific formation of (Z)-3-(benzothiazolyl-2-thio)-3-phenyl-2-propenonitrile (88%).
- Nosyreva,Andriyankova,Mal'kina,Afonin,Trofimov
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- 2-Benzothiazolyl-N-(arenesulfonyl)-sulfinimidoyl fluorides
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2-Benzothiazolyl-N-(arenesulfonyl)sulfinimidoyl fluorides were synthesized by the treatment of benzothiazolyl-2-sulfur trifluoride with sulfonamides. The reaction of 2-benzothiazolyl-N(p-toluenesulfonyl)-sulfinimidoyl fluoride with tert-butylamine and morpholine gave 2-benzothiazolyl-N-(arenesulfonyl)- sulfinimidoyl amides. The reaction of 2-benzothiazolyl-N-(p-toluenesulfonyl)- sulfinimidoyl fluoride or 2-benzothiazolyl-15N-(p-tosyl)sulfinimidoyl fluoride with S-trimethylsilylbenzenethiol gave di(benzothiazolyl-2) disulfide, fluorotrimethylsilane and N,N′-bis(p-toluenesulfonyl)-N,N′- bis(phenylthio)-hydrazine or 15N,15N′-bis(p- toluenesulfonyl)-15N, 15N′-bis(phenylthio)- hydrazine, respectively.
- Pashinnik, Valeriy E.,Guzyr, Alexander I.,Borovikov, Alexei V.,Shermolovich, Yuriy G.
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- Copper-Catalyzed Domino Synthesis of Sulfur-Containing Heterocycles Using Carbon Disulfide as a Building Block
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In this paper, we describe the successful development of an efficient domino method for the synthesis of C-3 sulfenylated imidazo[1,2-a]pyridine derivatives applying carbon disulfide as a readily available, cheap and easy-to-handle building block. Most importantly, a single copper catalyst mediates two type reactions and three chemical bonds are formed in a one-pot organic transformation. The developed method provids an attractive alternative approach to various potentially bioactive sulfur-containing heterocycles, and will find broad applicability in organic synthesis and pharmaceutical chemistry. (Figure presented.).
- Gan, Ziyu,Yan, Qiuli,Li, Guoqing,Li, Qin,Dou, Xiaomeng,Li, Guang-Yao,Yang, Daoshan
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- Chemical Interactions between 2-Mercaptobenzazoles and ?-Acceptors
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2-Mercaptobenzazoles (1a-c) interact with several ?-acceptors such as tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL), dicyanomethyleneindane-1,3-dione (CNIND), 2,3-dicyano-1,4-naphthoquinone (DCNQ), 9-dicyanomethylene-2,4,7-trinitrofluorene (DTF), and 2,3-dichloro-1,4-naphthoquinone (DCHNQ) via the formation of charge-transfer (CT) complexes to yield various heterocyclic compounds. - Keywords: 2-Mercaptobenzazoles; Molecular interactions; ?-Acceptors
- Hassan, A. A.,Mohamed, N. K.,El-Tamany, E. H.,Ali, B. A.,Mourad, A. E.
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- PdCl2/DMSO-Catalyzed Thiol-Disulfide Exchange: Synthesis of Unsymmetrical Disulfide
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Unsymmetrical disulfides have been effectively prepared through thiol exchange with symmetrical disulfides employing a simple PdCl2/DMSO catalytic system. The given method features excellent functional group tolerance, a broad substrate scope, and operational simplicity. This reaction is especially useful for late-stage functionalization of bioactive scaffolds such as peptides and pharmaceuticals. Disulfide-containing organic dyes have also been prepared. This transformation could be extended to thiol-diselenide or thiol-ditelluride exchange affording RS-SeR′ or RS-TeR′.
- Guo, Jimin,Zha, Jianjian,Zhang, Tao,Ding, Chang-Hua,Tan, Qitao,Xu, Bin
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supporting information
p. 3167 - 3172
(2021/05/05)
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- Copper-Catalyzed Coupling Reactions of Cyclobutanone Oxime Esters with Sulfur Nucleophiles at Room Temperature
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A copper-catalyzed iminyl radical-mediated C-C bond cleavage/cross-coupling tandem reaction of cyclobutanone oxime esters with aryl thiols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) at room temperature was developed, and aryl cyanopropyl sulfides were smoothly synthesized in 20-88% yields. By altering the copper reagent and the molar ratio of cyclobutanone oxime ester/aryl thiol/DBU, substitutional product N-arylthio cyclobutanone imines were selectively generated in 50-91% yields. Using this protocol, C-S bond and N-S bond formations using aryl thiols as sulfur sources were realized under very mild conditions without the use of photocatalysis and electrocatalysis techniques.
- He, Mingchuang,Yan, Zhaohua,Zhu, Fuyuan,Lin, Sen
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p. 15438 - 15448
(2019/01/04)
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- Disulfide Bond-Containing Ajoene Analogues As Novel Quorum Sensing Inhibitors of Pseudomonas aeruginosa
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Since its discovery 22 years ago, the bacterial cell-to-cell communication system, termed quorum sensing (QS), has shown potential as antipathogenic target. Previous studies reported that ajoene from garlic inhibits QS in opportunistic human pathogen Pseudomonas aeruginosa. In this study, screening of an in-house compound library revealed two sulfur-containing compounds which possess structural resemblance with ajoene and inhibit QS in bioreporter assay. Following a quantitative structure-activity relationship (SAR) study, 25 disulfide bond-containing analogues were synthesized and tested for QS inhibition activities. SAR study indicated that the allyl group could be replaced with other substituents, with the most active being benzothiazole derivative (IC50 = 0.56 μM). The compounds were able to reduce QS-regulated virulence factors (elastase, rhamnolipid, and pyocyanin) and successfully inhibit P. aeruginosa infection in murine model of implant-associated infection. Altogether, the QS inhibition activity of the synthesized compounds is encouraging for further exploration of novel analogues in antimicrobial drug development.
- Fong, July,Yuan, Mingjun,Jakobsen, Tim Holm,Mortensen, Kim T.,Delos Santos, May Margarette Salido,Chua, Song Lin,Yang, Liang,Tan, Choon Hong,Nielsen, Thomas E.,Givskov, Michael
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p. 215 - 227
(2017/04/26)
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- Method for preparing 2,2'-dithiodibenzothiazole from waste residues generated during process of AE-active ester production
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The invention relates to a method for preparing 2,2'-dithiodibenzothiazole from waste residues generated during the process of AE-active ester production. The method comprises the following steps: dissolving waste residues generated during the process of AE-active ester production into methanol, adding a catalyst (tetrabutyl ammonium bromide), introducing ozone into the reactions system at a temperature of 40 to 45 DEG C, carrying out reactions for 1 to 1.5 hours under stirring, after the reactions (a), stopping introducing ozone, keeping on stirring, maintaining the reaction temperature for 1 to 1.5 hours, then cooling to a temperature of 5 to 10 DEG C, filtering, and drying the reaction product in vacuum to obtain 2,2'-dithiodibenzothiazole. The provided method can high efficiently recover M from the waste residues generated during the process of AE-active ester production so as to produce high purity DM; moreover, the provided method has the advantages of simple technology, mild conditions, safety, and easiness in controlling, the used solvent is easy to recover and generates little pollution, the production cost is low, and the preparation method is suitable for large scale production.
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Paragraph 0025; 0026; 0027; 0028; 0029
(2016/10/27)
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- A mild radical method for the dimerization of dithiocarbamates
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A general, practical, and efficient method for the dimerization of dithiocarbamates has been developed that can be used to prepare the corresponding bis(1-arylimino-1-alkyl/ arylthiomethyl) disulfides with dilauroyl peroxide (DLP) as mild oxidant. Notably, a lauroyl radical, rather than an undecyl radical, was established as the radical hydrogen-ab- stractor during the dimerization process. The amount of DLP impacts the dimerization yield, with 50 mol-% DLP giving the disulfides in the highest yields. The use of an excess of DLP generates the undecyl radical, which decomposes the disulfides rapidly to the corresponding isothiocyanates.
- Chen, Ning,Zhong, Xin,Li, Pingfan,Xu, Jiaxi
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supporting information
p. 802 - 809
(2015/02/19)
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- Reaction of some 2-quinolone derivatives with phosphoryl chloride: Synthesis of novel phosphoric acid esters of 4-hydroxy-2-quinolone
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3-Chloroquinoline-2,4-diones do not react with phosphoryl chloride, however, 2,4-dichloroquinolines and/or 4-chloroquinolin-2-ones are formed in the presence of N,N-dimethylaniline. Along with these compounds, small quantities of novel dihydrogen phosphates of 4-hydroxyquinolin-2-ones were isolated. We outline a simple procedure that allows for the preparation of these compounds in moderate to good yields. All compounds were characterized by 1H and 13C NMR, IR, EI-MS, and ESI-MS spectroscopy, and in select cases by 31P NMR spectroscopy.
- Rudolf, Ondrej,Mrkvicka, Vladimir,Lycka, Antonin,Rouchal, Michal,Klasek, Antonin
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p. E100-E110
(2013/06/04)
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- Homogeneous photodegradation study of 2-mercaptobenzothiazole photocatalysed by sodium decatungstate salts: Kinetics and mechanistic pathways
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The photochemical degradation of a benzothiazole derivative, 2-mercaptobenzothiazole (MBT) has been studied in aqueous solution in the presence of a polyoxometalate (POM): sodium decatungstate salts Na4W10O32 (DTA). In aerated conditions, the photodegradation rate of MBT clearly increased in the presence of DTA by a factor six when compared with the direct photolysis with kMBT = 0.25 h-1 and t1/2(MBT) = 2.8 h. For the total comprehension of the degradation mechanism, the oxygen influence has been investigated. Oxygen appeared essential for DTA regeneration, its absence induced a three times inhibition of MBT disappearance and completely stopped the photocatalytic cycle. The main photoproducts were identified with LC-ESI-MS and LC-DAD techniques and using some calculations obtained by B3LYP/6-21G method in Gaussian 4.1 software. All the results allowed to propose a mechanistic pathway. Electron transfer and H atom abstraction processes involving W10O324-* excited state species were involved in the degradation. In the primary step of the degradation, the hydroxylation of the aromatic ring leading to four OH-MBT isomers and the formation of disulfide form of MBT were observed. For longer irradiation time, a secondary electron transfer permitted the oxidation of OH-MBT isomers and the formation of sulfoxide derivatives. For prolonged exposure (around 100 h), the complete mineralization was noticed in the presence of sodium decatungstate salts.
- Allaoui,Malouki,Wong-Wah-Chung
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experimental part
p. 153 - 160
(2010/11/17)
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- 1-Methyl-3-phenyl-3-thiocyanato-1H,3H-quinoline-2,4-dione: A Novel Thiocyanating Agent
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Under mild reaction conditions, the thiocyanato group is selectively transferred from 1-methyl-3-phenyl-3-thiocyanato-1H,3H-quinoline-2,4-dione (3) to some nucleophiles. Aliphatic primary and secondary amines are converted to S-cyanothiohydroxylamines, anilines afford p-thiocyanatoanilines, Wittig reagent is thiocyanated in α-position, and thiols are oxidized to disulfides.
- Klasek, Antonin,Mrkvicka, Vladimir
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p. 747 - 752
(2007/10/03)
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- Heterocycle-substituted stable thioaminyl radicals: Isolation, ESR spectra, and magnetic properties
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N-[(2-Benzothiazolyl)thio]- (1), N-[(2-benzoxazolyl)thio]- (2), and N-(2-pyrimidylthio)-2,4,6-trisubstituted-phenylaminyls (3) were generated by oxidation of the corresponding amines. Although 2 and were not sufficiently persistent to be isolated, I was very persistent and could be isolated as radical crystals. The ESR spectra of nondeuterated and partially deuterated 1-3 radicals were measured, and the spin density distributions were estimated from the hyperfine coupling constants. Ab initio molecular orbital calculations were made for 1 to discuss the spin density distribution in more detail. Single-crystal X-ray crystallographic analysis was performed for one radical. Magnetic properties were measured for isolated four radicals with a SQUID. Two radicals showed ferromagnetic interaction, and analyses of (x)T vs T plots with the one-dimensional regular Heisenberg model gave 2J/k(B) =5.8 and8.6K. The remaining two radicals showed antiferromagnetic interaction. Analyses of the (x)T vs T plots with the Curie-Weiss law or dimer model gave Θ = -1.4 K and 2J/k(B) = -1370K. The strong antiferromagnetic interaction could be explained in terms of the X-ray crystallographic results.
- Miura,Tomimura,Teki
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p. 7889 - 7895
(2007/10/03)
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- Reaction of O,O-Dialkyl Hydrogen Phosphodithioates with 2-Benzothiazolylsulfenomorpholide and N-Cyclohexyl-2-benzothiazolylsulfenamide
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Reactions of O,O-dipropyl hydrogen phosphodithioate with 2-benzothiazolylsulfenomorpholide and N-cyclohexyl-2-benzothiazolylsulfenamide yield various derivatives of O,O-dipropyl hydrogen phosphodithioates and 2-mercaptobenzothiazole.
- Shaikhiev,Fridland,Musin
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p. 1874 - 1877
(2007/10/03)
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- Ozonation of thioamide containing heterocycles. A new general and selective procedure for the synthesis of C-2 substituted heteroazole derivatives
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2-Mercaptoheteroazoles readily react with ozone in the presence of nucleophiles and under mild experimental conditions to form several C-2 substituted heterazoles.
- Saladino, Raffaele,Crestini, Claudia,Occhionero, Francesca,Nicoletti, Rosario
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p. 3241 - 3251
(2007/10/03)
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- Use of a sacriflcial-sulfur electrode in electroorganic chemistry. V. Formation of the sequence CSSSC from S and thiols or thiolates
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At a working potential of about +2.0 V (vs SCE) the carbon-sulfur electrode is a source of the electrogenerated cation S2+. In organic media, this electrophile reacts with thiols (or thiolates) to give a mixture of polysulfides of which the trisulfide is the main product. The reaction between electrogenerated Sy2- and alkyl halides is less selective. Elsevier,.
- Do, Quang Tho,Elothmani, Driss,Simonet, Jacques,Guillanton, Georges Le
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p. 273 - 281
(2007/10/03)
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- Facile desulfurization of cyclic thioureas by hydrogen peroxide in acetic acid.
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A simple, mild and synthetically useful method for the desulfurization of cyclic thioureas and related compounds, existing as thiol-thione tautomeric mixtures, by hydrogen peroxide in acetic acid is proposed. The effect of substituting different solvents for the acetic acid was investigated.
- Grivas,Ronne
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p. 225 - 229
(2007/10/02)
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- 4-Oxazetidine-2-sulphinic Acid Derivatives; Preparation and Determination of Configuration by 1H Nuclear Magnetic Resonance Spectroscopy
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Reaction of 4-oxoazetidine-2-sulphinyl chlorides 1 with amines gave diastereoisomeric sulphinamides 6 and 7.Oxidation of the isomers 6 and 7 afforded the corresponding sulphonamides 12.From the reaction of the sulphinyl chlorides 1 with 2-mercaptobenzothiazole, disulphides 9a, 9b and 10 were isolated.Treatment of sulphinates 4a and 5a with aluminum trichlorideanisole afforded acids 4e and 5e, which can be converted into mixed anhydrides 4f and 5f.The absolute configurations of the sulphinates 4 and 5 and sulphinamides 6 and 7 were assigned on the basis of 1H NMRspectroscopic studies and verified by X-ray structure analysis of sulphinate 4b.
- Herak, Jure J.,Vinkovic, Mladen,Kojic-Prodic, Biserka
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p. 1201 - 1226
(2007/10/02)
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- OXIDATION OF 2-MERCAPTOBENZOHETERAZOLES BY DIMETHYLDIOXIRANE. A NEW METHOD FOR A SYNTHESIS OF C-2 SUBSTITUTED BENZIMIDAZOLE, BENZOXAZOLE, AND BENZOTHIAZOLE DERIVATIVES
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New and efficient reactions in which 2-mercaptobenzoheterazoles are selectively converted by dimethyldioxirane, under mild experimental conditions, to several C-2 substituted benzoimidazole, benzoxazole, and benzothiazole derivatives are reported.
- Frachey, Giuseppe,Crestini, Claudia,Bernini, Roberta,Saladino, Raffaele,Mincione, Enrico
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p. 2621 - 2630
(2007/10/02)
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- PERFLUOROALKYLATION OF 2-MERCAPTOBENZOTHIAZOLE AND ITS ANALOGUES WITH PERFLUOROALKYL IODIDES BY AN SRN1 REACTION
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The thiolates, generated in situ by the reaction of 2-mercaptobenzothiazole (1) and its analogues (2) and (3) with sodium hydride, react under UV irradiation with perfluoroalkyl iodides (4)-(8) to give the corresponding heteroaromatic perfluoroalkyl sulfides (9)-(18) in 50-98percent yields.The fact that the UV irradiation increases the conversion of perfluoroalkyl iodides and that the radical scavenger di-tert-butylnitroxide suppresses the reaction demonstrates that the reaction proceeds via an SRN1 mechanism.
- Chen, Qing-Yun,Chen, Mei-Jin
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- 6-amino-2-benzothiazolesulfonamide and topical treatment compositions and method for glaucoma
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A topical composition for eye treatment of glaucoma, comprising a small but pharmaceutically effective amount of an analog of benzothiazole-2-sulfonamide. The most preferred compound is 6-amino-2-benzothiazolesulfonamide. The invention also relates to a method of topically treating glaucoma with eye drops to reduce intraocular pressure. Finally, disclosed is a method of synthesis of the preferred and highly effective benzothiazole-2-sulfonamide analogs, particularly the 6-amino-2-benzothiazolesulfonamide compound.
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- STUDIES ON FLUORINE CONTAINING HETEROCYCLIC COMPOUNDS: 4. REACTIONS OF 3-NITRO-4-CHLOROBENZOTRIFLUORIDE AND 3,5-DINITRO-4-CHLOROBENZOTRIFLUORIDE WITH FIVE MEMBERED HETEROCYCLES
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The reactions of 3-nitro-4-chlorobenzotrifluoride (1a) and 3,5-dinitro-4-chlorobenzotrifluoride (1b) with heterocycles (2-5) are described.Six S-linked and N-substituted heterocycles (6, 9-11, 13), such as 2-(2-nitro-4-trifluoromethylphenylthio)benzothiazole (9a), were prepared from the reactions of 1a with benzotriazole (2), 2-mercaptobenzothiazole (5a) and 2-mercaptobenzoxazole (5b) and from the reactions of 1b with 2, 1,2,4-triazole (3) and 5a in DMF respectively. 1a reacted with 2-mercaptothiazoline (4) to give the desired product 7 and bis(2-nitro-4-trifluoromethylphenyl) thioether (8). 3-(2-Benzoxazolyl)-2-benzoxazolinethione (15) was obtained from the reaction of 1b with 5b.The spectral data and elemental analyses were fully in accord with the proposed structures, and the possible mechanisms for these compounds and other by-products were discussed.
- Chen, Mei-Jin,Chi, Ching-Sung,Chen, Qing-Yun
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- Electrooxidative Cyclization of 4-Dithioazetidinones (Kamiya's Disulfides) A Facile Access to 2-(Substituted methyl)penicillinates
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A straightforward access to penicillinates bearing SCN and SeCN groups at the 2β-methyl group was performed by electrolysis of 4-dithioazetidinones in a two-phase system (aqueous and organic phases) in the presence of KSCN and KSeCN, respectively, while a mixture of 2β-azidomethyl derivative and its 2α-isomer (6/4) was obtained by a similar electrolysis with NaN3.
- Tanaka, Hideo,Tanaka, Motoaki,Hironaka, Yo-ichi,Nakai, Akira,Torii, Sigeru
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p. 1801 - 1804
(2007/10/02)
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- Process for preparation of 4-sulfonylthio azetidinone derivatives
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A process for preparing an azetidinone derivative represented by the formula STR1 wherein R1 is hydrogen, halogen or lower alkoxy, R2 is hydrogen, halogen, lower alkoxy, amino or a group STR2 (in which R5 is substituted or unsubstituted phenyl, substituted or unsubstituted phenylmethyl, substituted or unsubstituted phenoxymethyl, or substituted or unsubstituted benzoyl), or R1 and R2, when taken together, are carbonyl, R3 is substituted or unsubstituted phenyl, and R4 is hydrogen, optionally substituted hydrocarbon residue or acyl, silyl, sulfonyl or phosphonyl derived from inorganic acid or organic acid, the process comprising reacting a dithioazetidinone derivative represented by the formula STR3 wherein R1, R2 and R4 are as defined above and R9 is substituted or unsubstituted, nitrogen-containing aromatic heterocyclic residue with a compound represented by the formula wherein R3 and R9 are as defined above.
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- Photochemistry of Pesticides, 12. On the Photoconversion of 1,3-Dihydro-2-benzimidazole-2-thione, 2(3)-Benzothiazolethione, and 2-Chlorobenzothiazole
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The photoreactivity of 1,3-dihydro-2-benzimidazole-2-thione (1a) and 2(3)-benzothiazolethione (1b) has been studied in several solvents in the presence of oxygen with or without methylene blue as a sensitizer.The corresponding disulfides (5a, b), 2-oxo derivatives (2a, b), benzimidazole and benzothiazole (11a, b), and elemental sulfur have been characterized as the main products.The UV irradiation of the disulfides 5a, b results in the formation of the same product pattern as the thiones 1a, b.Photolysis of 2-chlorobenzothiazole (12) in acetonitrile gives a mixture of 2b, 2,2'-dibenzothiazole (13), while photolysis of 12 in ethanol yields 2b and 11b.Products and mechanisms are discussed and compared with previous studies in this area. - Key words: 1,3-Dihydro-2-benzimidazole-2-thione, 2(3)-Benzothiazolethione, 2-Chlorobenzothiazole, Photodegradation, Photooxidation
- Abdou, W. M.,Sidky, M. M.,Wamhoff, H.
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p. 1153 - 1158
(2007/10/02)
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- A New Dihydrothiazine Ring Closure for the Preparation of 3-Methylcephalosporins from Azetidinone Disulfides at 5-10 deg
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p-Nitrobenzyl (2 R, 3 R)-2-(benzothiazol-2'-yldithio)-α-isopropenyl-4-oxo-3-phenoxyacetylamino-azetidine-1-acetate (3a), readily prepared from penicillin V, is smoothly cyclized by ammonium acetate in a dimethyl sulfoxide/tetrahydrofuran mixture at 5-10 deg to the ceph-3-em ester (2a) in high yield.Other ethers (3b-d), but not the free acid (3e), behave in a similar way.The ceph-3-em esters can be readily de-esterified to the free acid (2e).
- Davis, Michael,Wu, Wen-Yang
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p. 1519 - 1526
(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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- Photoreactions of β-Ketosulphides: Aryl and Benzyl Phenacyl Sulphides and Related Compounds
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Photoreactions of aryl phenacyl sulphides were studied, particularly in regard to substituent and solvent effects.In general, aryl phenacyl sulphides Ar1SCH2COAr2 1 = p-tolyl, Ar2 = p-X-C6H4 (X = H, Cl, OH, OMe, and Ph), 2-thienyl, and 2-furyl; Ar1 = 2,4,6-trimethylphenyl, Ar2 = Ph and p-HOC6H4; Ar1 = 2-benzthiazolyl, Ar2 = Ph> underwent photochemical cleavage to disulphides (Ar1S)2 and ketones Ar2COMe.In a few cases a diketone (Ar2COCH2)2 was the only, or major, carbonyl photoproduct.Similar photochemical behaviour was shown by ketosulphides p-Me-C6H4SCH(R)COPh (R = PhCH2, PhCOCH2, and p-Me-C6H4S) and related acetophenone derivatives PhCOCH2SR (R = COPh, SO3Na, and SCH2COPh).In a few instances, from p-Me-C6H4SCH2COAr (Ar = Ph, p-Cl-C6H4, and p-Ph-C6H4), a minor photoproduct was a 2-aryl-5-methylbenzothiophen.Benzyl phenacyl sulphides p-X-C6H4COCH2SCH2Ph (X = OH and OMe) also underwent photo-cleavage to give dibenzyl disulphide and a ketone.Free-radical cleavage products ArCOCH2(.) (Ar = Ph and p-MeO-C6H4) and p-Me-C6H4S(.) were trapped as adducts p-Me-C6H4SC(Ph)2CH2CH2COAr when irradiation of the ketosulphide was carried out in the presence of 1,1-diphenylethylene. 2,5-Diphenylfuran was formed photochemically from 1,4-diphenylbutane-1,4-dione on irradiation in methanol.
- Arora, Kanwar J. S.,Collier, John R.,Deodhar, Dinker J.,Hesabi, Masoud-M.,Hill, John
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p. 2148 - 2183
(2007/10/02)
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- Importance of the C(3) Substituent of the Penam Derivative in Interconversion Reactions of Penam and Cepham Systems
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The azetidinone disulphide (1b), a structural analogue of Kamiya's disulphide (1a), has been synthesized.Some cyclization reactions of the disulphides (1) (Br2 in CH2Cl2 and AcOAg in ClCH2CO2H-CH2Cl2) leading to penal and cepham derivatives through episulphonium ions (2), have been studies.The data obtained show that changing the substituent X in (1a) and (1b) brings about changes in the distribution of the positive charge in the intermediate episulphonium ions (2a) and (2b), and thus affects to some extent the regioselectivity of the episulphonium ring opening and the chemical behaviour of (1a) and (1b).
- Balsamo, Aldo,Benedini, Paola Maria,Macchia, Bruno,Macchia, Franco,Rossello, Armando
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p. 413 - 417
(2007/10/02)
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- KINETICS OF PEROXIDE OXIDATION OF 2-MERCAPTOBENZOTHIAZOLE IN DILUTE AQUEOUS SOLUTIONS.
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The purpose of this work is to study the possibility of using hydrogen peroxide for preliminary removal of 2-MBT from water. Experimental results show that oxidation goes to completion only at elevated temperatures. The principal oxidation product is 2,2 prime -dibenzothiazolyl disulfide, which is precipitated. A small amount of benzothiazole, which remains in solution, is formed during the oxidation. Peroxide oxidation of 2-MBT in aqueous solutions can be used in industry for treatment of wastewaters containing this compound.
- Repkina,Ptitsyna,Latysheva
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p. 1082 - 1084
(2007/10/02)
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- DERIVATIVES OF SULFOXYLIC DIAMIDE
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N,N'-Disubstituted sulfur diimides are reduced by the action of thiophenols to N,N'-disubstituted sulfoxylic diamides R1NHSNHR2.Compounds where R1 = R2 = SO2Ar, COPh enter readily into reaction both with retention and with cleavage of the S-N bond.In reaction with secondary amines and CH acids they are "carriers of sulfur." 2,5-Diaroyl-1,2,5-thiadiazolidine-3,4-diones are formed by the successive action of trimethylchlorosilane and oxalyl chloride on the compounds where R1 = R2 = COPh, COC6H4Cl-p.
- Pel'kis, N. P.,Levchenko, E. S.
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p. 1963 - 1967
(2007/10/02)
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- INTERCONVERSION OF THE THIAZINE AND THIAZOLIDINE SYSTEM OF β-LACTAM ANTIBIOTICS. ELECTROCHEMICAL CLEAVAGE OF KAMIYA'S DISULPHIDE PROMOTED BY BROMIDE ION
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A new transformation of Kamiya's disulphide (1) into the bromopenam derivative (4) has been carried out by eletrolyzing the disulphide (1) in protic solvents in the presence of Me4NBr.The transformation occurs through an intermediate episulphonium-bromide ion pair in which the bromide appears to be tightly linked to the sulphur.
- Balsamo, Aldo,Benedini, Paola Maria,Giorgi, Irene,Macchia, Bruno,Macchia, Franco
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p. 2991 - 2994
(2007/10/02)
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- ELECTROCHEMICAL S-S BOND FISSION OF 4-(2-BENZOTHIAZOLYLDITHIO)AZETIDINONES (KAMIYA'S DISULFIDES)
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An electrochemical S-S bond fission of 4-(2-benzothiazolyldithio)azetidinones derived from penicillin G has been achieved by the selection of an appropriate electrolysis system, providing either 2β-halomethylpenicillins, 3β-halocephams, or 4-methoxysulfinylazetidinone derivatives.
- Torii, Sigeru,Tanaka, Hideo,Siroi, Takashi,Sasaoka, Michio,Saitoh, Norio,et al.
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p. 1829 - 1832
(2007/10/02)
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- Reactions of Mesoionic Five-Membered Heterocycles with o-Quinonoid Compounds, IV. Mono- and Tricyclic 1,3-Thiazolium-4-olates, 1,3-Dithiolylium-4-olates
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Monocyclic 1,3-thiazolium-4-olates (10) react with o-quinonoid compounds to give cycloadducts (12,13); tricyclic 1,3-thiazolium-4-olates (14,15) yield compounds (17,18,19,20) which can formally be derived from a ketene tautomer (C). 1,3-Dithiolylium-4-olates are borderline cases; both (32) and adducts (34) were obtained. - Keywords: o-Quinones, Heterocycles
- Friedrichsen, Willy,Schroeer, Wolf-D.,Schwarz, Ingo,Boettcher, Andreas
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p. 609 - 621
(2007/10/02)
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- A NOVEL ELECTROSYNTHESIS OF α,α-DIMETHOXYALKANOATES FROM α-(2-BENZOTHIAZOLYLTHIO)ALKANOATES
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An efficient preparation of α,α-dimethoxyalkanoates (2) has been performed by electrolytic desulfurization of α-benzothiazolylthio)alkanoates (1) in MeOH containing CuCl2 as a catalytic additive, yielding 2 (94-57percent) together with disulfide 3 (88-48percent).
- Torii, Sigeru,Okumoto, Hirosi,Tanaka, Hideo
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p. 617 - 618
(2007/10/02)
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