- RELAXATION OF THE SECOND EXCITED SINGLET OF AROMATIC THIONES: THE ROLE OF SPECIFIC SOLUTE-SOLVENT INTERACTIONS
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Second excited singlet state (S2) fluorescence quantum yields and lifetimes of six aromatic thiones have been measured in solution at room temperature.Intermolecular S2->S1 internal conversion dominates S2 decay in inert perfluoroalkane solvents, but intermolecular photochemical and photophysical processes dominate in more strongly interacting solvents.Stern-volmer quenching is observed when perfluoroalkane solutions of 2,2,3,3-tetramethylindanathione, a model thione, are spiked with addens at contrentations up to ca. 0.3 M.Measurements of the rate constans for the biomolecular quenching of S2 fluorescence by 26 different addends reveal that the thione S2 state is highly reactive and that the initial intermolecular interaction path divides into physical and chemical branches, the branching ratio being a function of the nature of the quecher.
- Maciejwski, A.,Demmer, D. R.,James, D. R.,Safarzadeh-Amiri, A.,Verrall, R. E.,Steer, R. P.
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- Spectral Dynamics of Nitro Derivatives of Xanthione in Solutions
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Nitro derivatives of xanthione, 2,7-dinitro-9H-xanthene-9-thione and 2,4,7-trinitro-9H-xanthene-9-thione, have been first synthesized and their stationary and transient spectra have been measured. The stationary spectra show that the attachment of the nit
- Bondarev, Stanislav L.,Tikhomirov, Sergei A.,Buganov, Oleg V.,Knyukshto, Valeri N.,Galinovskii, Nikolaii A.,Fedunov, Roman G.,Khokhlova, Svetlana S.,Ivanov, Anatoly I.
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- Generation of “Sumanenylidene”: A Ground-State Triplet Carbene on a Curved π-Conjugated Periphery
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We have observed the generation of sumanenylidene (2), a divalent, neutral-carbon species at the benzylic position of sumanene (1). We also clarified both experimentally and theoretically that the ground state of compound 2 was a triplet state and that its singlet–triplet energy gap (ΔEST) was similar to that in fluorenylidene. The curved structure of compound 2 led to slightly better spin delocalization over the two adjacent aromatic rings than in planar systems, because of the unpaired spins on the σ and π orbitals. Synthetic application of the carbene precursor, diazosumanene (5), with a variety of thiocarbonyl compounds revealed its utility for the preparation of tetrasubstituted alkene compounds (e.g., that contain a strongly electron-donating unit) that are directly conjugated to the sumanene (1) moiety.
- Yakiyama, Yumi,Wang, Yufeng,Hatano, Sayaka,Abe, Manabu,Sakurai, Hidehiro
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- Bistricyclic aromatic enes annelated with nopinane fragment
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Organic compounds, referred to as bistricyclic aromatic enes (BAE), are a subgroup among many sterically overcrowded alkenes and are widely studied as molecular switches. We have developed a new group of chiral BAE whose molecular structure combines dipinodiazafluorene fragment and chromophore/fluorophore (acridine, xanthene or thioxanthene moiety). The new compounds demonstrate mechanochromism, thermochromism, and solvatochromism/protonochromism. According to quantum chemical calculations (DFT PBE0/def2-TZVPP), the compounds synthesized are conformationally inhomogeneous, and the conformations should differ in the electronic absorption spectra, the population of conformational isomers should being dependent on the solvent and the acidity of the medium. The observed experimental facts (NMR data, UV spectra, chromism, X-ray data) are in good correlation with the calculated data.
- Vasilyev, Eugene S.,Bizyaev, Sergey N.,Komarov, Vladislav Yu,Tkachev, Alexey V.
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- Variations of bistricyclic aromatic enes: Mono-bridged tetraarylethene naphthologs
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The syntheses, molecular and crystal structures, NMR spectroscopic study, and DFT computational study of naphthologs of mono-bridged (X = -, O, S, Se, and Te) tetraarylethene (BAE-1s) 11-25 with α,α-, β,β-, and α,β-dinaphthalenyl substituents have been reported. The BAE-1s have been prepared by Barton-Kellog twofold extrusion from the respective chalcogenothiones and diazomethylenebisnaphthylenes. Complete assignments of 1H- and 13C-NMR spectra of 11-25 have been made through 2-dimensional correlation spectroscopy (DQF-COSY, HSQC, HMBC, and NOESY). The corresponding intermediates, thiiranes 33-47, have been also isolated (except 38), and their molecular and crystal structures have been determined. The molecular structures of BAE-1s 12-15, 20, and 22-25 adopted folded-twisted conformations with considerably folded (φ = 30°-57°) tricyclic moieties. The α,α- and α,β-dinaphthalenyl derivatives are more overcrowded than β,β-dinaphthalenyl derivatives. The relief of the steric strain due to the overcrowding around C9 = C9' caused by the presence of naphthalenyl substituents was achieved by their twisting around the single bonds that connect the α-naphthalenyl and β-naphthalenyl moieties to C9'. The 1H-NMR spectra have shown shielding of H2, H7 of 11-25 and the pronounced deshielding of H8', H8′ of α,α-dinaphthalenyl-substituted BAE-1s 13-15 in contrast to β,β-dinaphthalenyl-substituted BAE-1s 16-20. The upfield shifts of H2, H7 suggested conformations in which these hydrogens are located above the planes of the opposing naphthalene rings. DFT calculations of 11-20 have been performed at B3LYP/6-31G(d) and B3LYP/SDD. The results have shown that the global minima of BAE-1s without a chalcogen bridge 11 and 16 are twisted (-sc,-sc)-C 2-t conformations. The global minima of BAE-1s with a chalcogen bridge are folded-twisted (-sc,-ac)-C 1-ft conformations for α,α-dinaphthalenyl-substituted BAE-1s 12-15 and either anti- or syn-(-sc,ac)-C 1-ft conformations for β,β-dinaphthalenyl-substituted BAE-1s 17-20. The pronounced differences between the α,α-dinaphthalenyl and the β,β-dinaphthalenyl derivatives are noted. Dispersion-corrected B3LYP calculations stabilize significantly the α,α-dinaphthalenyl derivatives versus the β,β-dinaphthalenyl derivatives. The geometrical parameters of BAEs-1 11-15 and 20, derived from their molecular X-ray structures and from their B3LYP-optimized geometries are in a good agreement.
- Assadi, Naela,Pogodin, Sergey,Cohen, Shmuel,Agranat, Israel
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- Synthesis of Bicyclic P,S-Heterocycles via the Addition of Thioketones to a Phosphorus-Centered Open-Shell Singlet Biradical
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Formal addition reactions between the open-shell singlet biradical [P(μ-NTer)]2 (1Ter) and xanthione, thioxanthione, as well as ferrocenyl naphthyl thioketone were studied in detail. Reactions were performed at room temperature and led to the formation of strained [2.1.1]-cage P,S-heterocycles (3). All addition products were isolated and fully characterized by spectroscopic methods. Furthermore, reversible cleavage of the xanthenthione-biradical addition product into the parent compounds (biradical and thioketone) could be demonstrated by 31P{1H} NMR spectroscopy. The thermodynamic stability of all cyclization products with respect to the elimination of thioketone was studied by quantum-chemical computations including solvent effects. Regarding the dissociation of addition products 3 into the fragment molecules 1Ter and ketone/thioketone, calculations prove that a significantly larger distortion energy in ketones compared with thioketones causes lower thermodynamic stability of the ketone adducts.
- Beer, Henrik,Linke, Alexander,Bresien, Jonas,Mlostoń, Grzegorz,Celeda, Ma?gorzata,Villinger, Alexander,Schulz, Axel
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supporting information
p. 2031 - 2038
(2022/01/31)
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- One-Pot Catalytic Cleavage of C=S Double Bonds by Pd Catalysts at Room Temperature
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The C=S double bonds in CS2 and thioketones were catalytically cleaved by Pd dimeric complexes [(N∧N)2Pd2(NO3)2](NO3)2 (N∧N, 2,2′-bipyridine, 4,4′-dimethylbipyridine or 4,4′-bis(trifluoromethyl)) at room temperature in one pot to afford CO2 and ketones, respectively, for the first time. The mechanisms were fully investigated by kinetic NMR, isotope-labeled experiments, in situ ESI-MS, and DFT calculations. The reaction is involved a hydrolytic desulfurization process to generate C=O double bonds and a trinuclear cluster, which plays a pivotal role in the catalytic cycle to regenerate the dimeric catalysts with HNO3. Furthermore, the electronic properties of catalyst ligands possess significant influence on reaction rates and kinetic parameters. At the same temperature, the reaction rate is consistent with the order of electronegativity of N∧N ligands (4,4′-bis(trifluoromethyl) > 2,2′-bipyridine > 4,4′-dimethylbipyridine). This homogeneous catalytic reaction features mild conditions, a broad substrate scope, and operational simplicity, affording insight into the mechanism of catalytic activation of carbon sulfur bonds.
- Zhu, Ting,Wu, Xiaoxi,Yang, Xinzheng,Sharma, Bigyan,Li, Na,Huang, Jiaming,Wang, Wentao,Xing, Wang,Zhao, Zhenwen,Huang, Hui
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supporting information
p. 9266 - 9273
(2018/08/17)
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- A Turn-On Fluorescent Probe for Detection of Sub-ppm Levels of a Sulfur Mustard Simulant with High Selectivity
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A new type of fluorescent probe capable of detecting a sulfur mustard (SM) simultant at a concentration of 1.2 μM in solution and 0.5 ppm in the gas phase has been developed. Owing to its molecular structure with a thiocarbonyl component and two piperidyl
- Zhang, Yuanlin,Lv, Yanlin,Wang, Xuefei,Peng, Aidong,Zhang, Kaiquan,Jie, Xiaoke,Huang, Jijun,Tian, Zhiyuan
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p. 5481 - 5488
(2018/04/24)
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- Thioether compound and its preparation method (by machine translation)
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The invention discloses a thioether compound and its preparation method. The thioether compound having a structure of formula I its synthetic path from a 9 H - X mixed anthracene - 9 - keto starting, by vulcanization, coupling the two-step reaction can get the final compounds 9 - (R-based) - 9 - ((R yl) thio) - 9 H - X mixed anthracene. This kind of thioether compound in thermal free-radical polymerization can be certain initiating and regulating action, and can be with free radical chain is reversibly coupling - breaking reaction, so that the sleep-chain free radical formation, so that the polymerization shows certain controllability. In addition, the thioether compound in the light in the polymerization process can be used as a photoinitiator to initiate polymerization of the monomer, the polymer molecular weight and have shown certain regulating function. With the traditional "active"/controlled radical polymerization system compared with that is used in the reagent, the compound is non-toxic, odorless, colorless, non-metallic ion and the use of additional ligand and the like, in the free radical polymerization has a better application prospect. (by machine translation)
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Paragraph 0024; 0037; 0041
(2018/01/19)
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- Electronic structures and population dynamics of excited states of xanthione and its derivatives
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A new compound, 1,3-dimethoxy xanthione (DXT), has been synthesized and its absorption (stationary and transient) and luminescence spectra have been measured in n-hexane and compared with xanthione (XT) spectra. The pronounced broadening of xanthione vibr
- Fedunov, Roman G.,Rogozina, Marina V.,Khokhlova, Svetlana S.,Ivanov, Anatoly I.,Tikhomirov, Sergei A.,Bondarev, Stanislav L.,Raichenok, Tamara F.,Buganov, Oleg V.,Olkhovik, Vyacheslav K.,Vasilevskii, Dmitrii A.
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- Fluorescent probe for detecting hypochlorous acid as well as preparation method and application thereof
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The invention discloses a fluorescent probe for detecting hypochlorous acid as well as a preparation method and application thereof. The structural formula of the fluorescent probe is described in the specification, wherein R is H or hydroxyl. The fluorescent probe disclosed by the invention has high detection sensitivity to hypochlorous acid, small damage to tissues and strong penetrating power and can be clearly applied to in vivo imaging. According to he preparation method of the fluorescent probe, oxoxanthone or an oxoxanthone derivative reacts with a Lawson reagent to obtain a target product, namely the fluorescent probe used for detecting hypochlorous acid. The fluorescent probe disclosed by the invention is simple in synthesis method and is applicable to industrial production.
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Paragraph 0042; 0043; 0044; 0045; 0046; 0047-0051-0053
(2017/01/31)
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- A THIONATION PROCESS AND A THIONATING AGENT
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A process for transforming a group >C=O (I) in a compound into a group >C=S (II) or into a tautomeric form of group (II) in a reaction giving a thionated reaction product, by use of crystalline P2S5·2 C5H5N as a thionating agent. A thionating agent which is crystalline P2S5·2 C5H5N
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Page/Page column 17
(2012/08/27)
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- Thionations using a P4S10-pyridine complex in solvents such as acetonitrile and dimethyl sulfone
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Tetraphosphorus decasulfide (P4S10) in pyridine has been used as a thionating agent for a long period of time. The moisture-sensitive reagent has now been isolated in crystalline form, and the detailed structure has been determined by X-ray crystallography. The thionating power of this storable reagent has been studied and transferred to solvents such as acetonitrile in which it has proven to be synthetically useful and exceptionally selective. Its properties have been compared with the so-called Lawesson reagent (LR). Particularly interesting are the results from thionations at relatively high temperatures (165 °C) in dimethyl sulfone as solvent. Under these conditions, for instance, acridone and 3-acetylindole could quickly be transformed to the corresponding thionated derivatives. Glycylglycine similarly gave piperazinedithione. At these temperatures, LR is inefficient due to rapid decomposition. The thionated products are generally cleaner and more easy to obtain because in the crystalline reagent, impurities which invariably are present in the conventional reagents, P4S 10 in pyridine or LR, have been removed. 2011 American Chemical Society.
- Bergman, Jan,Pettersson, Birgitta,Hasimbegovic, Vedran,Svensson, Per H.
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experimental part
p. 1546 - 1553
(2011/06/11)
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- Dynamics of capsuleplex formed between octaacid and organic guest molecules - Photophysical techniques reveal the opening and closing of capsuleplex
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This manuscript is concerned with the opening and closing of a capsuleplex made up of organic guest molecules and two cavitand molecules known as octaacid (OA). The capsuleplex is loosely held together in water through weak interactions. We have investiga
- Jayaraj, Nithyanandhan,Jockusch, Steffen,Kaanumalle, Lakshmi S.,Turro,Ramamurthy
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supporting information; experimental part
p. 203 - 213
(2011/04/23)
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- Expeditious microwave-assisted thionation with the system PSCl 3/H2O/Et3N under solvent-free condition
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(Chemical Equation Presented) A novel thionation protocol for carbonyl compounds, with the system PSCl3/H2O/Et3N has been discovered. Clean, rapid, and efficient synthesis of a variety of thiocarbonyl compounds such as thioamides, thiolactams, thioketones, thioxanthones, and thioacridone can be achieved through this simple and convenient method under solventless condition with microwave irradiation.
- Pathak, Uma,Pandey, Lokesh Kumar,Tank, Rekha
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p. 2890 - 2893
(2008/09/19)
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- Polymorphism versus thermochromism: Interrelation of color and conformation in overcrowded bistricyclic aromatic enes
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The nature of the thermochromic form of overcrowded bistricyclic aromatic enes (BAEs) has been controversial for a century. We report the single-crystal X-ray structure analysis of the deep-purple and yellow polymorphs of 9-(2,7-dimethyl-9H-fluoren-9-ylidene)-9H-xanthene (11), which revealed the molecules in a twisted and a folded conformation, respectively. Therefore, the deeply colored thermochromic form B of BAEs is identified as having a twisted conformation and the ambient-temperature form A as having a folded conformation. This re lationship between the color and the conformation is further supported by the X-ray structures of the deep-purple crystals of the twisted 9-(9H-fluoren-9-ylidene)-9H-xanthene (10), and of the yellow crystals of the folded 9-(11H-benzo[b]fluoren-11-ylidene)-9H-xanthene (12). Based on this conclusive crystallographic evidence, eleven previ ously proposed rationales of thermochromism in BAEs are refuted. In the twisted structures, the tricyclic moieties are nearly planar and the central double bond is elongated to 1.40 A and twisted by 42°. In the folded structures, the xanthylidene moieties are folded by 45° and the fluorenylidene moieties by 18-20°. Factors stabilizing the twisted and folded conformations are discussed, including twisting of formal single or double bonds, intramolecular overcrowding, and the significance of a dipolar aromatic "xanthenylium-fluorenide" push-pull structure.
- Biedermann, P. Ulrich,Stezowski, John J.,Agranat, Israel
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p. 3345 - 3354
(2008/09/19)
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- Reactions of α-diazocamphor with aromatic thioketones
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The reactions of α-diazocamphor (6) with aromatic thioketones (9a-d) in dichloromethane at room temperature afforded mixtures of the stereoisomeric spirocyclic thiiranes (10) and (11). A reaction mechanism via [2+3] cycloaddition to give the spirocyclic 2,5-dihydro-1,3,4-thiadiazoles (13) and (14), subsequent elimination of nitrogen and 1,3-dipolar electrocyclization of the intermediate thiocarbonyl ylide (15) is proposed. The structure of the stereoisomers (10a) and (11a) has been established by X-Ray crystallography. Desulfurization of the mixtures (10/11) with triphenylphosphane in boiling THF yielded the alkylidene derivatives (12).
- Mloston, Grzegorz,Celeda, Malgorzata,Linden, Anthony,Heimgartner, Heinz
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- Second generation light-driven molecular motors. Unidirectional rotation controlled by a single stereogenic center with near-perfect photoequilibria and acceleration of the speed of rotation by structural modification
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Nine new molecular motors, consisting of a 2,3-dihydro-2-methylnaphtho[2,1-b]thiopyran or 2,3-dihydro-3-methylphenanthrene upper part and a (thio)xanthene, 10,10-dimethylanthracene, or dibenzocycloheptene lower part, connected by a central double bond, were synthesized. A single stereogenic center, bearing a methyl substituent, is present in each of the motors. MOPAC93-AM1 calculations, NMR studies, and X-ray analysis revealed that these compounds have stable isomers with pseudoaxial orientation of the methyl substituent and less-stable isomers with pseudoequatorial orientation of the methyl substituent. The photochemical and thermal isomerization processes of the motors were studied by NMR and CD spectroscopy. The new molecular motors all show two cis-trans isomerizations upon irradiation, each followed by a thermal helix inversion, resulting in a 360° rotation around the central double bond of the upper part with respect to the lower part. The direction of rotation is controlled by a single stereogenic center created by the methyl substituent at the upper part. The speed of rotation, governed by the two thermal steps, was adjusted to a great extent by structural modifications, with half-lives for the thermal isomerization steps ranging from t1/2θ 233-0.67 h. The photochemical conversions of two new motors proceeded with near-perfect photoequilibria of 1:99.
- Koumura, Nagatoshi,Geertsema, Edzard M.,Van Gelder, Marc B.,Meetsma, Auke,Feringa, Ben L.
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p. 5037 - 5051
(2007/10/03)
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- Microwave-accelerated solvent-free synthesis of thioketones, thiolactones, thioamides, thionoesters, and thioflavonoids
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Formula presented An expeditious, solvent-free, and high yield conversion of ketones, flavones, isoflavones, lactones, amides, and esters to the corresponding thio analogues is described utilizing Lawesson's reagent in a process that circumvents the use of dry solvents and excess of the reagent.
- Varma, Rajender S.,Kumar, Dalip
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p. 697 - 700
(2008/02/11)
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- Photochemical reactions of bianthrone and related substances
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Photocleavage reactions of a wide range of ethylene compounds were investigated. Photosensitized oxygenation resulted in formation of their corresponding ketones. On the other hand, photoreaction of these substrates with elemental sulfur yielded the corresponding thioketones. Furthermore, photobehaviour of some ethylene episulfides also was studied. It could be concluded that UV-irradiation provides a rapid and effective desactivation pathway for this class of compounds.
- Abdou, Wafaa M.,Elkhoshnieh, Yehia O.,Sidky, Mahmoud M.
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p. 3595 - 3602
(2007/10/02)
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- Studies on chromone derivatives: regioselective 1,3-dipolar and 1,4-cycloaddition reactions of 3-cyano-4H-1-benzopyran-4-thione
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1,3-Dipolar cycloaddition reactions of 3-cyano-4H-1-benzopyran-4-thione 1 with nitrilimines 3, nitrile oxides 7 and aldonitrones 8 yielded regioselective cycloadducts involving the thione function.In the latter two classes, the unstable cycloadducts fragmented to yield 3-cyanochromone 11 and isothiocyanate 12 or thioamide 13, respectively.In contrast, dienamines 14 preferred to react at the carbon-carbon double bond in a 1,4-cycloaddition yielding xanthione (9H-xanthene-9-thione) 16 by elimination of HCN and the amine moiety.Keywords: 1,3-dipolar cycloaddition / 1,4-cycloaddition / 4H-1-benzopyran-4-thione / nitrilimine / nitrile oxide / nitrone
- Sain, Bir,Prajapati, Dipak,Mahajan, Asha R,Sandhu, Jagir S
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p. 313 - 316
(2007/10/02)
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- PHOTOCHEMICAL REACTIONS OF SOME AROMATIC THIONES WITH BIS(TERT-BUTYLTHIO)ETHYNE. ISOLATION AND PROPERTIES IF THIETES, THE PHOTOCHEMICAL (2+2)-CYCLOADDUCTS AND THEIR ISOMERIC α,β-UNSATURATED DITHIOESTERS
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Photochemical reaction of some aromatic thiones 2 with bis(tert-butylthio)ethyne 1 affords the α,β-unsaturated dithio esters 4 via a (2+2)-cycloaddition reaction of the triplet-excited thiones 2 with acetylene 1.In one case, a (2+2)-cycloadduct, thiete 3o, was isolated.Spectroscopic investigations revealed that in solution there is an equilibrium between this thiete 3o and the isomeric α,β-unsaturated dithio ester 4o.The generality of this equilibrium phenomenom is examined and discussed with respect to the substituents of the C=C-C=S moiety of the α,β-unsaturated dithio ester 4.
- Brouwer, A. C.,George, A. V. E.,Bos, H. J. T.
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- C = C Double Bonds with Extreme Reactivity, III. Reactions of 9-(9-Fluorenylidene)xanthene
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According to equations (1) to (4), 9-(9-fluorenylidene)xanthene (2) reacts with sulfur, malonodinitrile, aniline, or thiophenol to give the compounds 3, 5, 7-11, and diphenyl disulfide.
- Schoenberg, Alexander,Singer, Erich,Stephan, Werner
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p. 3762 - 3765
(2007/10/02)
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- EXTREMELY REACTIVE CARBON-CARBON DOUBLE BONDS-I; REACTIONS WITH 2-(9-XANTHYLIDENE)-, 2-(9-THIOXANTHYLIDENE)-, AND 2-(9-FLUORENYLIDENE)-INDANE-1,3-DIONE. A CONTRIBUTION ON THE STRUCTURE AND REACTIVITY OF NON-PLANAR C-C DOUBLE BONDS
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The compounds in the title (cf 1a, 1b and 2) react with various reagents, often under mild conditions, mostly by breaking of the central double bond.According to X-ray diffraction the central double bond of 2-(9-xanthylidene)indane-1,3-dione is inclined by 47.2 deg.The relationship between the structure and reactivity of the compounds in the title is discussed.
- Schoenberg, Alexander,Singer, Erich,Stephan, Werner,Sheldrick, William S.
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p. 2429 - 2438
(2007/10/02)
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- Synthesis of α-Chlorothiosulfenyl Chlorides. A New Class of Reactive Organosulfur Compounds
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The reaction of various aromatic and suitably substituted aliphatic thiones with sulfur dichloride in dry carbon disulfide affords the corresponding α-chlorothiosulfenyl chlorides (R2C(Cl)SSCl), the first simple compounds of this type.Reaction of the α-chlorothiosulfenyl chlorides with triphenylphosphine regenerates the thiones, accompanied by the corresponding ketones.Possible mechanisms for these transformations are presented.
- Still, Ian W. J.,Kutney, Gerald W.,McLean, David
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p. 555 - 560
(2007/10/02)
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- STUDIES ON ORGANOPHOSPHORUS COMPOUNDS-XL. REACTIONS OF KETONES WITH 2,4-BIS(4-METHOXYPHENYL)-1,3,2,4-DITHIADIPHOSPHETANE 2,4-DISULFIDE
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Cyclohexanone and cyclopentanone react with (2,4-bis-4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (Lawesson Reagent (LR)) at 80 deg C with formation of new spiro-1,3,5,2-trithiaphosphorines 1 and 2, respectively. 2-Methyl and 2-phenylcyclohexanone also react with LR at 80 deg C producing the enethiols 3 and 4, which on storage are transformed into the sulfides 5 and 6.Unsaturated cyclohexanones 7-9 are transformed into the corresponding thioketones 10-12 after reactions with LR at 60 deg C for a few hours. 2-Hydroxyketones react with LR with formation of 1,3,2-oxathiaphospholes and similarly a 2-aminoketone gave a 1,3,2-thiazaphosphole.Aromatic ketones, reacted with LR to give corresponding thioketones.Thiofluorenone dimerized to form the cyclic disulfide 31, as proved by X-ray analyses.
- Scheibye, S.,Shabana, R.,Lawesson, S.-O.,Romming, C.
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p. 993 - 1002
(2007/10/02)
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- Organosulfur Compounds, L. - 2H-Thiopyrans and Dihydro-2H-thiopyrans, Synthons for Thiophenes
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2H-Thiopyran derivatives yield thiophenes on pyrolysis at 240-260 deg C.The influence of substitution in positions 3 to 6 of the 2H-thiopyrans on these new thermal rearrangement and fragmentation reactions is dealt with, and some proposed mechanisms are discussed in detail.A novel three-step synthesis of thiophenes from carbonyl compounds via the corresponding thiones, their -cycloaddition with 1,3-dienes with formation of dihydro-2H-thiopyrans and subsequent thermal conversion is described.In this reaction sequence, whose scope and limitations are outlined, t he thiocarbonyl compound contributes the sulfur and the 1,3-diene the carbon skeleton of the desired thiophenes.
- Praefcke, Klaus,Weichsel, Christian
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p. 1604 - 1619
(2007/10/02)
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