- Thiylation of functionalized electrophiles with sulfur in basic reductive systems
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Functionalized electrophiles, specifically acetyl chloride, benzoyl chloride, chloroacetylchloride, benzenesulfonyl chloride, and N,N,4-trichlorobenzenesulfonamide, were brought into reaction with sulfur in the systems hydrazine hydrate-NaOH and sodium sulfide-water-ethanol. The efficiencies of these systems were compared. The reaction of chloroacetyl chloride with sulfur in the system hydrazine hydrate-base afforded new types of polymeric compounds, poly[(diacylhydrazine)polysulfides]. The reaction mechanisms were discussed.
- Deryagina,Russavskaya,Grabel'nykh
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Read Online
- Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
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A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
- Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
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supporting information
p. 2020 - 2024
(2022/03/31)
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- Visible Light-Induced Amide Bond Formation
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A metal-, base-, and additive-free amide bond formation reaction was developed under an organic photoredox catalyst. This green approach showed excellent functional selectivity without affecting other functional groups such as alcohols, phenols, ethers, esters, halogens, or heterocycles. This method featured a broad substrate scope, good compatibility with water and air, and high yields (≤95%). The potential utilities were demonstrated by the synthesis of important drug molecules such as paracetamol, melatonin, moclobemide, and acetazolamide.
- Song, Wangze,Dong, Kun,Li, Ming
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supporting information
p. 371 - 375
(2019/11/29)
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- Amide Synthesis from Thiocarboxylic Acids and Amines by Spontaneous Reaction and Electrosynthesis
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Amide bond formation is one of the most important basic reactions in chemistry. A catalyst-free approach for constructing amide bonds from thiocarboxylic acids and amines was developed. The mechanistic studies showed that the disulfide was the key intermediate for this amide synthesis. Thiobenzoic acids could be automatically oxidized to disulfides in air, thioaliphatic acids could be electro-oxidized to disulfides, and the resulting disulfides reacted with amines to give the corresponding amides. By this method, various amides could be easily synthesized in excellent yields without using any catalyst or activator. The successful synthesis of bioactive compounds also highlights the synthetic utility of this strategy in medicinal chemistry.
- Tang, Li,Matuska, Jack H.,Huang, Yu-Han,He, Yan-Hong,Guan, Zhi
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p. 2570 - 2575
(2019/06/13)
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- Reaction of Thiocarboxylic Acids with N-tert-Butyl-2-halo-2-methylpropanimines
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Reaction of N-tert-butyl-2-chloro-2-methylpropanimine with thiocarboxylic acids has proceeded by two routes, one involving nucleophilic substitution of the chlorine atom in the primary iminium salt by acylthio group, and another via reduction of its catio
- Khairullin,Gazizov,Kirillina, Yu. S.,Ivanova, S. Yu.,Bashkirtseva, N. Yu.,Karimova
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p. 111 - 113
(2018/07/29)
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- Visible light driven amide synthesis in water at room temperature from Thioacid and amine using CdS nanoparticles as heterogeneous Photocatalyst
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Highly efficient photocatalytic thioacid mediated amide synthesis at room temperature using CdS nanoparticles as photocatalyst was observed under a household 30?W CFL in water. The operationally mild reaction was tolerant to a number of functional group substitutions on amine and could be scaled up to gram. This heterogeneous photocatalyst was extremely stable and could easily be recovered by simple centrifugation for at least six recycling reactions without any significant loss of catalytic performance. The possible reaction mechanism for the photocatalytic thioacid mediated amide synthesis over the CdS semiconductor has also been proposed on the basis of experimental observations.
- Das, Sudipto,Ray, Shounak,Ghosh, Abhisek Brata,Samanta, Partha Kumar,Samanta, Suvendu,Adhikary, Bibhutosh,Biswas, Papu
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- Reaction of N-tert-butyl-2-haloaldimines with thiolcarboxylic acids
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The reactions of N-tert-butyl-2-chloroaldimine with thiolcarboxylic acids occurs along two pathways: nucleophilic substitution of chlorine in the primary iminium salt by acylmercapto group and reduction of the C–Cl bond in the iminium cation. The reaction
- Khairullin,Gazizov,Kirillina, Yu. S.,Gazizova,Khayarov, Kh. R.
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p. 2736 - 2738
(2017/12/26)
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- Phosphorothioate anti-sense oligonucleotides: The kinetics and mechanism of the generation of the sulfurising agent from phenylacetyl disulfide (PADS)
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The synthesis of phosphorothioate oligonucleotides is often accomplished in the pharmaceutical industry by the sulfurisation of the nucleotide-phosphite using phenylacetyl disulfide (PADS) which has an optimal combination of properties. This is best achieved by an initial 'ageing' of PADS for 48 h in acetonitrile with 3-picoline to generate polysulfides. The initial base-catalysed degradation of PADS occurs by an E1cB-type elimination to generate a ketene and acyldisulfide anion. Proton abstraction to reversibly generate a carbanion is demonstrated by H/D exchange, the rate of which is greatly increased by electron-withdrawing substituents in the aromatic ring of PADS. The ketene can be trapped intramolecularly by an o-allyl group. The disulfide anion generated subsequently attacks unreacted PADS on sulfur to give polysulfides, the active sulfurising agent. The rate of degradation of PADS is decreased by less basic substituted pyridines and is only first order in PADS indicating that the rate-limiting step is formation of the disulfide anion from the carbanion.
- Scotson, James L.,Andrews, Benjamin I.,Laws, Andrew P.,Page, Michael I.
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p. 8301 - 8308
(2016/09/09)
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- Potassium Thioacids Mediated Selective Amide and Peptide Constructions Enabled by Visible Light Photoredox Catalysis
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A remarkable visible-light-promoted photoredox catalytic methodology involved with amines and eco-friendly potassium thioacids for amide formation was uncovered. This approach can mimic the natural coenzyme acetyl-CoA to selectively acylate amines without affecting other functional groups such as alcohols, phenols, esters, among others. The developed strategy may hold great potential for a comprehensive display of biologically interesting peptide synthesis and amino acid modification through a diacyl disulfide intermediate.
- Liu, Hongxin,Zhao, Liyun,Yuan, Yunfei,Xu, Zhifang,Chen, Kai,Qiu, Shengxiang,Tan, Haibo
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p. 1732 - 1736
(2016/03/15)
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- 3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) mediated metal-free mild oxidation of thiols to disulfides in aqueous medium
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Thiols are efficiently oxidized to disulfides (RSSR) in the presence of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) in aqueous medium, as well as in the absence of a solvent under mild and metal-free conditions. A broad range of alkyl, aryl and heterocyclic symmetrical disulfides can be easily obtained in almost quantitative yields. The X-ray single crystal structure of 2-aminocyclopent-1-ene-1-carbothioic dithioperoxyanhydride (disulfide obtained from 2-aminocyclopentene-1-dithiocarboxylic acid, ACDA) is reported. The reaction mechanism has been studied thoroughly. It is shown that the reaction proceeds through the formation of an organosulphur radical. Pytz interacts with thiol to accept one electron and produces an organosulphur radical. Pytz ultimately accepts two electrons to form H2pytz and is capable of oxidizing 2 equivalents of thiols.
- Samanta, Suvendu,Ray, Shounak,Ghosh, Abhisek Brata,Biswas, Papu
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p. 39356 - 39363
(2016/06/01)
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- 4,4'-Azopyridine as an easily prepared and recyclable oxidant for synthesis of symmetrical disulfides from thiols or alkyl halides(tosylates)/thiourea
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Heterocyclic azo compounds, prepared from corresponding amines in one step, are used as effective oxidants for the conversion of thiols into symmetrical disulfides in high yields. Among the studied azo compounds, 4,4'-azopyridine was found to be very efficient for the odorless conversion of alkyl halides into disulfides in the presence of thiourea. An attractive feature of this azo compound is that its obtained solid side product hydrazine is easily separated by filtration and can be recycled to its azo compound for further use.
- Khalili, Dariush,Iranpoor, Nasser,Firouzabadi, Habib
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p. 544 - 555
(2015/10/19)
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- One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea
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An efficient and odourless procedure for a one-pot synthesis of thioesters by the reaction of benzoic anhydrides, thiourea and various organic halides (primary, allylic, and benzylic) or structurally diverse, electron-deficient alkenes (ketones, esters, and nitriles) in the presence of Et3 N has been developed. In this method, thiobenzoic acids were in situ generated from the reaction of thiourea with benzoic anhydrides, which were subjected to conjugate addition with electron-deficient alkenes or a nucleophilic displacement reaction with alkyl halides.
- Abbasi, Mohammad,Khalifeh, Reza
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p. 1265 - 1273
(2015/08/18)
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- Novel radical tandem 1,6-enynes thioacylation/cyclization: Au-Pd nanoparticles catalysis versus thermal activation as a function of the substrate specificity
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We studied the reactivity of 1,6-enynes with thioacetic acid (AcSH) under either thermal conditions or in the presence of catalytic amounts of supported Au or Au-Pd nanoparticles (NPs) under mild conditions. The 1,6-enynes undergo a tandem thioacylation/cyclization to original cyclic products featuring either a homoallylic thioester function or an enol thioester function depending on the substrate topology. Interestingly, the former process was found more efficient when performed in the presence of Au-Pd NPs while the latter process can be efficiently carried out under thermal conditions (100 °C). The reaction proceeds by a radical mechanism and the presence of precious metal NPs seems to stabilize the formation of free radical intermediates, as supported by experimental and theoretical results.
- Notar Francesco, Irene,Giauffret, Justine,Fontaine-Vive, Fabien,Edwards, Jennifer K.,Kiely, Christopher J.,Hutchings, Graham J.,Antoniotti, Sylvain
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p. 9635 - 9643
(2015/01/08)
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- Efficient synthesis of unsymmetrical disulfides
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A novel way of synthesizing unsymmetrical disulfides from thiols with DDQ is presented here. This procedure ran in a straightforward manner to give high product yields. Unsymmetrical disulfides were directly synthesized from the corresponding mixture of thiols in equimolar amounts under mild conditions.
- Vandavasi, Jaya Kishore,Hu, Wan-Ping,Chen, Chung-Yu,Wang, Jeh-Jeng
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experimental part
p. 8895 - 8901
(2011/11/30)
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- Silver(I) catalyzed oxidation of thiocarboxylic acids into the corresponding disulfides and synthesis of some new Ag(I) complexes of thiophene-2-thiocarboxylate
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Aromatic thiocarboxylic acids in presence of a base on treatment with silver nitrate under ambient conditions were oxidized to the corresponding disulfides. The reactions were found to be catalyzed by Ag+ ions. The catalytic oxidation is paralleled by the Ag(SCOAr) complex formation reaction which could be considerably subsided by adjustment of the reaction conditions. Attempts to use [Ag(PPh3)2]+ or [Ag(PPh 3)]+ ion as the catalyst were unsuccessful as these resulted in the formation of the corresponding thiocarboxylate complexes. The products, ArCOSSCOAr (1, 2), [Ag(SCOAr)(PPh3)2] (3, 4) and [Ag(SCOAr)(PPh3)]4 (5) (Ar = C6H5, C4H3S) were characterized by single crystal X-ray analysis. Compounds 3 and 4 are monomeric while 5 is a cyclic tetramer in the crystalline phase.
- Singh, Suryabhan,Chaturvedi, Jyotsna,Bhattacharya, Subrato,N?th, Heinrich
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experimental part
p. 93 - 97
(2011/02/27)
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- FUNCTIONALIZED POLYMERS USING PROTECTED THIOLS
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A process for the preparation of functional molecules using the thiol-ene coupling reaction and a process for the preparation of protected functional thiols, specifically thioesters is provided. The methods may be used to make functional polymers and other molecules. The method of making a functionalized polymer using a thiol-ene reaction comprises: providing a functionalized thioester having the following formula: (I) wherein R is a functional group and COR' is a protecting group; cleaving the functionalized thioester, forming a functional thiol and an acyl group; providing a polymer having a pendant vinyl group; and reacting the polymer with the functional thiol whereby a functionalized polymer is formed, wherein the functional thiol is not isolated prior to reacting with the polymer.
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Page/Page column 35-36
(2009/05/28)
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- The rapid and efficient synthesis of disulfides from alkyl and acyl halides
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Various symmetrical dialkyl and diacyl disulfides are prepared easily in high yields from the corresponding alkyl and acyl halides under mild and nonaqueous conditions using N,N'-dibutyl-N,N,N',N'-tetramethyl- ethylenediammonium tetrahydroborate (BTMETB) or N,N'-dibenzyl-N,N,N',N'- tetramethylethylenediammonium tetrahydroborate (BZTMETB) and elemental sulfur. The quaternary diammonium borohydrides were easily prepared by treatment of the corresponding quaternary diammonium chloride or bromide with alkaline solution of sodium borohydride at room temperature.
- Tajbakhsh, Mahmood,Lakouraj, Moslem M.,Mahalli, Majid S.
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experimental part
p. 1453 - 1456
(2009/12/04)
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- A facile method for the synthesis of diacyl disulfides
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A facile method for the synthesis of diacyl disulfides is reported. Sulfur is reduced with samarium diiodide at room temperature to give samarium disulfides, which react with acyl chlorides in the presence of HMPA to afford the corresponding diacyl disulfides in high yields.
- Jia, Xue-Shun,Liu, Xiao-Tao,Li, Qing,Huang, Qing,Kong, Ling-Long
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p. 547 - 548
(2007/10/03)
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- N-Phenyltriazolinedione as an efficient, selective, and reusable reagent for the oxidation of thiols to disulfides
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N-Phenyltriazolinedione is an efficient and chemoselective reagent for the oxidation of thiols to their corresponding symmetrical disulfides. The method is applicable to aromatic, aliphatic, and bi-functional thiols. The one-pot reaction takes a few minutes (in most cases studied) for completion and after a simple work-up affords the corresponding symmetrical disulfides in very good to excellent yields. Furthermore, the reaction could be performed with the same results in the absence of solvent for liquid thiols.
- Christoforou, Angelos,Nicolaou, Georgia,Elemes, Yiannis
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p. 9211 - 9213
(2007/10/03)
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- Method for preparing aromatic diphenyl thioethers
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The invention concerns a method for preparing aromatic diphenyl thioethers. More particularly the invention concerns the preparation of 4-chloro-4′-thiomethyldiphenylether. The inventive method for preparing an aromatic diphenyl thioether is characterised in that it consists in reacting in an aqueous medium a diazonium salt of an aromatic diphenyl compound with a disulphide sulphur compound, in the presence of an efficient amount of a coupling catalyst.
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- Synthesis of diacyl disulfides using a polymer supported reagent
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Various diacyl disulfides are prepared easily in high yields from the corresponding acid chlorides under mild and non-aqueous conditions using a polymer supported reagent obtained from elemental sulfur and Amberlyst (OH)- . The polymeric reagent is regenerable.
- Tamami,Kiasat
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p. 1275 - 1280
(2007/10/03)
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- Nucleophilic substitution of acyl chlorides by electrogenerated polysulfide ions in N,N-dimethylacetamide
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The reactions between acyl chlorides RC(O)Cl (a) [R = Me (1), Pri (2), Bui (3), Ph(4)] and electrogenerated S3._(? S62-) ions have been investigated in N,N-dimethylacetamide by spectroelectrochemistry. With R = alkyl, thiocarboxylate ions and sulfur resulting from the fast initial substitutions cause partial formation of both acyl disulfide ions and diacyl disulfides (b) at a y ratio [RC(O)C1]/[S3._] of 0.5; the second step stoichiometrically (y = 1) affords diacyl disulfides 1b-4b as the presumed products. The formation of these species only is confirmed on a preparative scale from two sets of experiments: (i) direction addition of acyl chlorides (1a-4a) to chemically generated S1/3- solutions; (ii) electrolysis of sulfur in the presence of acyl chlorides 2a-4a.
- Robert, Julie,Anouti, Meriem,Abarbri, Mohamed,Paris, Jacky
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p. 1759 - 1764
(2007/10/03)
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- Formation of acyldisulfide ions from the reaction of sulfur with thiocarboxylate ions, and reactivity towards acyl chlorides in N,N-dimethylacetamide
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The reactivity of sulfur towards thiocarboxylate ions RC(O)S- a (R = Ph 1, Me 2, Bu′ 3) has been studied by spectroelectrochemistry in N,N-dimethylacetamide. For 2a-3a, two parallel and partial reactions, for which equilibrium constants have been determined, led to: (i) [RC(O)]2S2- b species and S3·-/S82- polysulfide ions and (ii) RC(O)S2 ions c; only traces of 1c were detected by voltammetry. As previously observed with thiolate ions, our results are consistent with an initial monoelectronic transfer between RC(O)S- ions and S2 molecules in equilibrium with S8, followed by concurrent couplings of RC(O)S· and S2·- radicals. On a preparative scale, when sulfur was added to RC(O)S- ions 1a,3a the enhanced reactivity of RC(O)S2- ions towards acyl chlorides RC(O)Cl (R = C6H5 and Bu′, respectively) only yielded diacyl disulfides 1b,3b.
- Robert, Julie,Anouti, Meriem,Paris, Jacky
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p. 473 - 478
(2007/10/03)
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- A convenient method for the synthesis of diacyl disulfides
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A simple and general method for the synthesis of diacyl disulfides is reported. Sulfur is allowed to react with sodium hydroxide to give sodium disulfide at 65°C under PTC, which can react with acyl halides to afford diacyl disulfides in good to excellent isolated yields. The effects of solvents and phase transfer catalysts are discussed.
- Wang,Cui,Hu,Zhao
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p. 889 - 898
(2007/10/02)
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- Structure-activity relationship study of synthetic hydrazines as ecdysone agonists in the control of spruce budworm (Choristoneura fumiferana)
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A quantitative structure-actitivty relationship study was performed for a number of aroylhydrazine compounds with respect to their biological ativity against spruce budworm.It was found that the biological activity can be modulated by substituents on the aromatic rings.Substituents with high ? value and small L value lead to increase in biological activity.Molecular mechanics calculations were used to explain how the active compounds may mimic the strong-binding Y region of ecdysone. Key words: spruce budworm, ecdysone, agonist, hydrazines, quantitative structure- activity relationship.
- Mohammed-Ali, Anmar M.,Chan, Tak-Hang,Thomas, Anthony W.,Strunz, George M.,Jewett, Brent
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p. 550 - 557
(2007/10/02)
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- Highly Selective Sulfur Transfer Reaction in the Solid State
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Benzyltriethylammonium tetrathiomolybdate 1 reacts readily with benzyl halides, alkyl iodides and acyl halides in the solid state to give the corresponding disulfides in good yields and with remarkable selectivity.
- Ramesha, A. R.,Chandresekaran, Srinivasan
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p. 767 - 768
(2007/10/02)
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- OXIDATION OF SOME THIO ACIDS BY 2,6-DICHLOROPHENOL INDOPHENOL IN NEUTRAL AND ALKALINE MEDIUM BY SPECTROPHOTOMETRIC STOPPED FLOW TECHNIQUE
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Using spectrophotometric stopped flow technique, the oxidation of thiolactic acid, thioglycollic acid, 3-mercaptopropionic acid and thiobenzoic acid by the dye, 2,6-dichlorophenol indophenol, has been investigated.The reaction shows first order kinetics with respect to thioacids and 2,6-dichlorophenol indophenol concentrations while zero order kinetics with respect to hydroxide ion concentrations.Neither of the reaction products viz. the disulfide or the leuco-dye, affects the rate.Similarly, the addition of neutral electrolyte also does not influence the rate.The data suggest the formation of an activated complex between thioacids and the oxidant which in turn slowly decomposes into the intermediate product. Key words: Stopped flow technique; thioacids; 2,6-dichlorophenol indophenol; disulphide; leuco-dye.
- Singh, H. S.,Tandon, P. K.,Singh, S. K.,Jaiswal, A. K.
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p. 193 - 204
(2007/10/02)
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- Synthesis of Disulfides via Sulfenylation of Alkyl and Aryldithiopyridine N-Oxides
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Alkyl and aryldithiopyridine N-oxides were prepared by reaction of 2,2'-dithiopyridine-1,1'-dioxide with various thiols in high yields.Some of the mixed disulfide products could in turn be used to sulfenylate efficiently other thiols.Therefore, practical and efficient synthetic methods for both symmetrical and unsymmetrical disulfides were developed.
- Barton, Derek H. R.,Chen, Chen,Wall, G. Michael
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p. 6127 - 6138
(2007/10/02)
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- Synthesis of isothiocyanates by reaction of amides with carbon disulfide in the presence of solid potassium carbonate/sodium hydroxide mixture
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Readily available N-monosubstituted trifluoroacetamides are transformed into isothiocyanates in good yield by reaction, at room temperature, with carbon disulfide in acetonitrile in the presence of anhydrous sodium hydroxide/potassium carbonate basic mixture.
- Albanese,Penso
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p. 1001 - 1002
(2007/10/02)
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- PHOTOCHEMICAL AND THERMAL REACTIONS OF HETEROCYCLES. IV. PHOTO-OXIDATION REACTIONS OF MESOIONIC DITHIOLIUMOLATE, THIAZOLIUMOLATE, AND RELATED HETEROCYCLES. SOLVENT EFFECTS ON THE COURSE OF THE PHOTO-OXIDATION
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Photo-oxidation of mesoionic 1,3-dithiolium-4-olates (1) gave diacyl disulfide (2), and that of a mesoionic thiazolium-4-olate (6) and oxazolium-5-olate (9) gave diacylamides as the main products.The formation of these products was rationalized by a route involving fragmentation of the corresponding endoperoxides, which are formed by cycloaddition of singlet oxygen on the mesoionic rings.Photo-oxidation of 5(4H)-oxazolones (12) and a 5(4H)-thiazolone (17) in dichloromethane gave the corresponding dehydro-dimers, while that of the former in dimethylformamide gave mainly diacylamides.The acylamides were considered to arise via the endoperoxides of the mesoionic tautomers.
- Kato, Hiroshi,Tani, Kazue,Kurumisawa, Haruki,Tamura, Yoshiko
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p. 1313 - 1322
(2007/10/02)
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- THERMAL REARRANGEMENT OF O-THIOACYL DERIVATIVES OF N-ACYL-N-ARYLHYDROXYLAMINES
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The ability of the Ar-N-O-C=S system of atoms to undergo a thermal rearrangement of the Claisen type was investigated.On the basis of the experimental data it was concluded that the process is predominantly nonconcerted in nature.
- Drozd, V.N.
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p. 317 - 326
(2007/10/02)
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- Reactions of 1,2-Dimethyl-3,5-diphenylpyrazolium-4-olate and 3,5-Diphenyl-1,2-dithiolylium-4-olate with Singlet Oxygen
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The pyrazolium-4-olate 1a and 1,2-dithiolylium-4-olate 1b react with singlet oxygen to produce carbon monoxide and 1,2-dibenzoyl-1,2-dimethylhydrazine (5a) or dibenzoyl disulfide (5b), respectively.
- Gotthardt, Hans,Schenk, Karl-Heinz
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p. 762 - 765
(2007/10/02)
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- Use of Potassium Bromate. Oxidation of Organic Sulphur Compounds
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Oxidation of various organic sulphur compounds by potassium bromate under different experimental conditions was studied.
- Adak, Mohini Mohan,Banerjee, Gopal Chandra,Banerjee, Amalendu
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p. 224 - 228
(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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- Photochemical and Thermal Transformations of S-Benzoyl-O-alkyl Xanthates
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The reaction of benzoyl chloride with different potassium-O-alkyl xanthates (n-propyl, iso-propyl, n-butyl) around 0 deg C afforded good yields of corresponding S-benzoyl-O-alkyl xanthates.The structure of these aroyl xanthates were consistent with the spectral data.Aroyl xanthates have been reported to be resistant to photolysis.It has, however, been observed in the present investigation that the fragmentation of these S-benzoyl-O-alkyl xanthates does occur on prolonged photolysis.Irradiation of these xanthates in benzene solution with mercury lamp for 60-70 hr resulted in the formation of benzoyl disulfide.Thermal decomposition around 250 deg C for 15 min gave benzoyl disulfide, corresponding ester and carbon disulfide.
- Darji, R. R.,Shah, A.
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p. 657 - 659
(2007/10/02)
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- Neue Reaktionen mesoionischer 1,3-Dithiolone mit Singulett- und Triplett-Sauerstoff
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Photochemically generated singlet oxygen combines with the 2,5-diaryl-1,3-dithiolylium-4-olates 1a, b in the presence of methanol to produce methyl phenylglyoxylate (6) and the disulfides 4a, b as a result of a fragmentation of the primarily formed cycloadducts of type 2.Whereas 1a, b show no reactivity towards triplet oxygen, the mesoionic 1,3-dithiolone 1c reacts with triplet oxygen at room temperature with formation of a 2,5,7-trithiabicycloheptanone derivative 10, whose structure is established by an X-ray crystal structure analysis.
- Gotthardt, Hans,Huss, Otmar M.,Schoy-Tribbensee, Sabine
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p. 285 - 291
(2007/10/02)
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- PHOTOOXIDATION OF SOME MESOIONIC AND RELATED SYSTEMS
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Photooxidation of several mesoionic compounds gave ring cleavage products, some of which were apparently formed via the endoperoxides of the mesoionic rings.Photooxidation of a Δ2-oxazolin-4-one and Δ2-thiazolin-4-one gave the corresponding 4,4'-bisoxa- and bisthiazolinone in dichloromethane, whereas the former gave benzamide in dimethylformamide.
- Kato, Hiroshi,Tani, Kazue,Kurumisawa, Haruki,Tamura, Yoshiko
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p. 717 - 720
(2007/10/02)
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- Stereospecific Transformations of Steroidal 2,3-Aziridines into Substituted Amino-thiols and Ring-A Fused Heterocycles
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1'-Acetyl-2β,3β-dihydro- and 1'-acetyl-2α,3α-dihydro-androst-2-enoazirin-17-one reacted with thiobenzoic S-acid to give the expected trans-diaxial ring-opened products, together with unexpected N-benzoyl-aziridines arising from transacylation.A mixed thioanhydride is postulated in a reaction pathway leading to the latter products. Classical trans-diaxial ring-opening and cyclization concepts were exemplified in ring-expansion reactions of aziridine derivatives to give chemospecific and stereoselective routes to a range of ring-A fused thiazolines and ring-A fused imidazothiazolines.
- Campbell, Malcolm M.,Craig, Raymond C.
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p. 766 - 774
(2007/10/02)
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