- Synthesis of Chiral Polycyclic Tetrahydrocarbazoles by Enantioselective Aminocatalytic Double Activation of 2-Hydroxycinnamaldehydes with Dienals
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An efficient aminocatalytic enantioselective double-activation strategy has been developed that combines several different aminocatalytic modes in a cascade process, such as iminium ion, vinylogous iminium ion, trienamine, and dienamine activations. By using this strategy, 2-hydroxycinnamaldehydes worked well with various dienals via [4 + 2] cycloaddition and the oxa-Michael reaction-initiated cascade, respectively, leading to chiral polycyclic tetrahydrocarbazole and chromane derivatives with excellent diastereo- and enantioselectivities.
- Ming, Yong-Chao,Lv, Xue-Jiao,Liu, Ming,Liu, Yan-Kai
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- THE POTENTIALLY ANTIAROMATIC (4N-?) α-HETERONAPHTHALENYL ANIONS
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Representative members of the title family of compounds were generated in liquid ammonia, and the "thia" analog 2c was sufficiently stable as to be directly examined by NMR.
- Anastassiou, A. G.,Kasmai, H. S.,Naderi, B.
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- Enhanced photochemical sensitivity in photochromic diarylethenes based on a benzothiophene/thiophene nonsymmetrical structure
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Photosensitivity of molecules is one of the central subjects of organic photochemistry. In this article, we present how and why a benzothiophene moiety impacts the photochromic quantum yield for the photochemical pericyclic ring closing of the hexatriene moiety. Two compounds were prepared: a symmetrical one incorporating two fluorenylthiophene units, and its corresponding nonsymmetrical partner, where one of the thiophene units was replaced by a benzothiophene group. Interestingly, the latter presents relatively high cyclization quantum yield (0.74), a value close to the largest one so far reported. Based on crystal structures, VT-NMR data and DFT calculations, we demonstrate that introducing a benzothiophene in the molecular scaffold induces skeleton stiffening by means of CH-π interactions and steric repulsions, and leads to increased population of the reactive conformer in the ambient conditions.
- Galangau, Olivier,Kimura, Yuka,Kanazawa, Rui,Nakashima, Takuya,Kawai, Tsuyoshi
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- Synthesis and photochromic properties of functional diarylethenes with a [1,3]dithiol-2-one (Thione) bridging unit
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In designing new photochromic compounds for optical data storage and photoswitching devices, the synthesis of a series of 4,5-diaryl-1,3-dithiol-2- one and 4,5-diaryl-1,3-dithiol-2-thione, which are suitable building blocks for incorporation with fluorophore, is herein reported. Our strategy needs the preliminary preparation of diarylalkynes, obtained by successive Sonogashira-Hagihara coupling-reactions in good yields (63-92%). A combination of these synthetic precursors with diisopropylxanthogen disulfide leads to the corresponding 4,5-diaryl-1,3-dithiol-2-ones under radical conditions with excellent yields (54-70%). The thionation of these compounds is obtained nearly quantitatively with phosphorous pentasulfide.
- Impagnatiello,Heynderickx,Moustrou,Samat
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- Palladium catalyzed cross-methylation of bromoheterocycles with intramolecularly stabilized dimethyl indium reagents
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Although the intramolecularly stabilized [(3- dimethylamino)propyl]dimethylaluminum (1a) fails to undergo palladium-catalyzed cross-coupling with bromopyridines and with bromofuran derivatives, the analogous gallium and indium reagent lb and 1c smoothly c
- Jaber, Nimer,Schumann, Herbert,Blum, Jochanan
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- Regiochemical selectivity in the Carbon-Sulfur bond cleavage of 2-methylbenzothiophene: Synthesis, characterization, and mechanistic study of reversible insertion into a C-S bond
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Thermolysis of (C5Me5)Rh(PMe3)(Ar)(H) (Ar = Ph or 3,5-xylyl) with 2-methylbenzothiophene at early reaction times yields a C-H activation compound and a single C-S insertion product resulting from insertion of rhodium into the S-C bond adjacent to the methyl substituent, 2k. Prolonged heating results in the conversion of 2k to the isomer in which the metal has inserted into the C-S bond adjacent to the aryl group via an intramolecular pathway, 2t. Both 2k and 2t were characterized by 1H, 31P, and 13C NMR spectroscopies and by single crystal X-ray diffraction. The kinetic product crystallized as a racemic twin in the orthorhombic space group P212121, with a = 8.5438(1) ?, b = 12.8079(2) ?, c = 19.3021(3) ?, Z = 4, and V = 2112.19(5) ?3, while the thermodynamic product crystallized in the triclinic space group P1 with a = 8.669(6) ?, b = 8.86(1) ?, c = 15.8(1) ?, α = 76.42(9)°, β = 86.66(7)°, γ = 74.46(9)°, Z = 2, and V = 1091.5(1.9) ?3.
- Myers, Andrew W.,Jones, William D.,McClements, Shawn M.
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- Cleavage of Furan-2-yl, 2-Thienyl-, Benzofuran-2-yl-, and Benzothiophen-2-yl-methyl(trimethyl)silanes (RCH2SiMe3) by Methanolic Sodium Methoxide; Acidities of the Corresponding RCH3 Species
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Rates of cleavage of RCH2SiMe3 by 2.00M-NaOMe in MeOH or MeOD at 50 deg C have been determined for R = furan-2-yl, 2-thienyl, benzofuran-2-yl, and benzothiophen-2-yl; the values of 1E5ks in MeOH and (in parentheses) in MeOD, where ks is the specific second order rate constant, are, respectively: 0.070 (0.167), 0.26 (0.52), 165 (310), and 70 (130) dm3 mol-1 s-1.The values of the ratios of ks in MeOH to hat in MeOD are in the range 0.42-0.54, consistent with rate-determining separation of the carbanion RCH2-. s is 1.57 (1.55), the ratio is 1.01, consistent with electrophilic assistance by proton transfer from the solvent to the separating carbon centre.> The results are discussed in the light of the deprotonation energies calculated (STO-3G) for the corresponding carbon acids RCH3, and approximate pKa values are derived for the latter, viz. (R =) furan-2-yl, 40.6; 2-thienyl, 39.7; benzofuran-2-yl, 35.2; benzothiophen-2-yl, 35.8.
- Dembech, Pasquale,Seconi, Giancarlo,Eaborn, Colin,Rodriguez, Juan A.,Stamper, John G.
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- A new Zn/TiCl4/LiAlH4 mediated approach to 2-aryl- or 2-alkyl-substituted benzothiophenes via intramolecular cyclization
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Methyl 2-(substituted benzoylthio)benzoates undergo intramolecular ring cyclizations in the presence of Zn/TiCl4/LiAlH4 to give the corresponding 2-aryl- or alkylsubstituted benzothiophenes in good yields. Georg Thieme Verlag Stuttgart.
- Hyung, Jae Jeong,Un, Young Yoon,Sang, Hun Jang,Yoo, Un-Aeh,Su, Nam Kim,Ba, Tai Truong,Sung, Chul Shin,Yoon, Yong-Jin,Okram, Mukherjee Singh,Lee, Sang-Gyeong
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- Diastereoselective self-assembly of a triple-stranded europium helicate with light modulated chiroptical properties
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Chiroptical photoswitches are of increasing interest for their potential in advanced information technologies. Herein, an achiral bis-β-diketonate ligand (o-L) with a photoresponsive diarylethene moiety as a linker was designed, which co-assembled with Eu3+ions andR- andS-bis(diphenylphosphoryl)-1,10-binaphthyl (R/S-BINAPO) as chiral ancillaries to form dinuclear triple-stranded helicates, [Eu2(o-L)3(R/S-BINAPO)2]. The helicates in the enantiopure form were confirmed by1H,19F,31P NMR and DOSY NMR analyses. Furthermore, the mirror-image CD and CPL spectra also demonstrate the existence of stable ground- and excited-state chiralities in solution. When exposed to alternate ultraviolet and visible light, the helicates showed reversible color variations from colorless to purple, followed by the presence of light-triggered quadruple optical and chiroptical outputs, named CD, PL, CPL andglumswitches. With these light-modulated optical outputs, the possibility for the fabrication of IMPLICATION and INHIBIT logic gates was discussed.
- Zhang, Zhihui,Zhou, Yanyan,Gao, Ting,Yan, Pengfei,Zou, Xiaoyan,Li, Hongfeng
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p. 4604 - 4612
(2021/04/12)
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- Di(benzothienyl)cyclobutenes: Toward Strained Photoswitchable Fluorophores
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Bis(benzothienyl)ethene sulfones are very interesting molecules for super-resolution microscopy due to their photoswitching properties. However, functionalization of the ‘classical’ bis(benzothienyl)ethene sulfones with a five-membered central ring leads to significant decrease of quantum yields of photoconversion of the fluorescent closed form of the dye to the non-fluorescent open form that limits their application in microscopy. Here, we designed and synthesized diarylethenes with a fluorinated four-membered central ring that adds extra strain to the closed form of the dye. The reaction mechanism of their formation was studied, and byproducts formed upon structural rearrangement of the benzothiophene fragment were characterized. The photochromic properties of the new molecules were investigated by NMR and absorption spectroscopy. Some of these compounds show enhanced tendency to ring opening and have quantum yields of the ring-opening reaction in the range of 0.2–0.5.
- Klepetá?ová, Blanka,Pohl, Radek,Procházková, Eli?ka,Semenenko, Aleksander,Shishkina, Svitlana,Shvadchak, Volodymyr,Sysoiev, Dmytro,Yushchenko, Dmytro A.
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p. 2084 - 2092
(2020/10/06)
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- A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
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Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
- Feng, Boya,Yang, Yudong,You, Jingsong
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p. 6031 - 6035
(2020/07/10)
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- Metal-directed synthesis of quadruple-stranded helical Eu(iii) molecular switch: A significant improvement in photocyclization quantum yield
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The self-assembly of a quadruple-stranded Eu(iii) helicate induces the conformation transformation of a DAE-based photochromic ligand from parallel to antiparallel, which brings a significant improvement in the photocyclization quantum yield (Φo-c) as compared with the free ligand. Furthermore, the photocontrolled open- and closed-rings of the ligand realized a reversible modulation toward Eu3+ center emission.
- Gao, Ting,Li, Hongfeng,Yan, Pengfei,Zhang, Yuan,Zhou, Yanyan
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supporting information
p. 13213 - 13216
(2020/11/09)
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- Lithium-Free Synthesis of Sodium 2,2,6,6-Tetramethylpiperidide and Its Synthetic Applications
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Lithium-free synthetic methods for sodium 2,2,6,6-tetramethylpiperide (NaTMP) have been developed using sodium dispersion as a sole sodium source. The prepared NaTMP was used as a Br?nsted base, that exhibited some differences in reactivities from LiTMP. (Figure presented.).
- Asako, Sobi,Kodera, Masato,Nakajima, Hirotaka,Takai, Kazuhiko
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supporting information
p. 3120 - 3123
(2019/05/22)
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- METHOD FOR SYNTHESIZING SODIUM 2,2,6,6-TETRAMETHYLPIPERIDIDES
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There is a demand for the development of a technique according to which sodium 2,2,6,6-tetramethylpiperidides (Na-TMPs) can be economically and efficiently synthesized through simple operations including a small number of steps under mild conditions in a short period of time. Also, there is a demand for the development of a technique according to which high-quality Na-TMPs that do not contain lithium or lithium compounds such as Li-TMP can be synthesized. The method for synthesizing sodium 2,2,6,6-tetramethylpiperidides includes a step of obtaining sodium 2,2,6,6-tetramethylpiperidides by reacting, in a reaction solvent, 2,2,6,6-tetramethylpiperidines with a dispersion product obtained by dispersing sodium in a dispersion solvent or an organosodium compound having an aromatic ring obtained through a reaction with a dispersion product obtained by dispersing sodium in a dispersion solvent.
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Paragraph 0127; 0130; 0131; 0132; 0133
(2019/12/10)
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- Highly Efficient Enantioselective Synthesis of Chiral Sulfones by Rh-Catalyzed Asymmetric Hydrogenation
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A highly efficient and enantioselective Rh-(R,R)-f-spiroPhos complex catalyzed hydrogenation of a series of unsaturated sulfones has been developed. With Rh-(R,R)-f-spiroPhos catalyst under mild conditions, not only the asymmetric hydrogenation of both the 3,3-diaryl and exocyclic α,β-unsaturated sulfones was first realized with up to 99.9% ee but also 3-alkyl-3-aryl and benzo[b]thiophene-1,1-dioxides were successfully hydrogenated to the corresponding chiral sulfones with excellent enantioselectivities (up to 99.4% ee) regardless of the steric hindrance, electronic property, and geometry of the substrates. Moreover, this reaction offers a route to (S)-(+)-ar-turmerone as a spice flavor, which is an important synthetic intermediate of pharmaceuticals.
- Yan, Qiaozhi,Xiao, Guiying,Wang, Ying,Zi, Guofu,Zhang, Zhanbin,Hou, Guohua
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supporting information
p. 1749 - 1756
(2019/01/25)
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- Palladium-Catalyzed Methylation of Aryl, Heteroaryl, and Vinyl Boronate Esters
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A method for the direct methylation of aryl, heteroaryl, and vinyl boronate esters is reported, involving the reaction of iodomethane with aryl-, heteroaryl-, and vinylboronate esters catalyzed by palladium and PtBu2Me. This transformation occurs with a remarkably broad scope and is suitable for late-stage derivatization of biologically active compounds via the boronate esters. The unique capabilities of this method are demonstrated by combining carbon-boron bond-forming reactions with palladium-catalyzed methylation in a tandem transformation.
- Haydl, Alexander M.,Hartwig, John F.
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supporting information
p. 1337 - 1341
(2019/02/26)
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- Decarbonylative Methylation of Aromatic Esters by a Nickel Catalyst
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A Ni-catalyzed decarbonylative methylation of aromatic esters was achieved using methylaluminums as methylating agents. Dimethylaluminum chlorides uniquely worked as the methyl source. Because of the Lewis acidity of aluminum reagents, less reactive alkyl esters could also undergo the present methylation. By controlling the Lewis acidity of aluminum reagents, a chemoselective decarbonylative cross-coupling between alkyl esters and phenyl esters was successful.
- Okita, Toshimasa,Muto, Kei,Yamaguchi, Junichiro
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p. 3132 - 3135
(2018/05/28)
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- Trimethylphosphate as a Methylating Agent for Cross Coupling: A Slow-Release Mechanism for the Methylation of Arylboronic Esters
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A methyl group on an arene, despite its small size, can have a profound influence on biologically active molecules. Typical methods to form a methylarene involve strong nucleophiles or strong and often toxic electrophiles. We report a strategy for a new, highly efficient, copper and iodide co-catalyzed methylation of aryl- and heteroarylboronic esters with the mild, nontoxic reagent trimethylphosphate, which has not been used previously in coupling reactions. We show that it reacts in all cases tested in yields that are higher than those of analogous copper-catalyzed reactions of MeOTs or MeI. The combination of C-H borylation and this methylation with trimethylphosphate provides a new approach to the functionalization of inert C-H bonds and is illustrated by late-stage methylation of four medicinally active compounds. In addition, reaction on a 200 mmol scale demonstrates reliability of this method. Mechanistic studies show that the reaction occurs by a slow release of methyl iodide by reaction of PO(OMe)3 with iodide catalyst, rather than the typical direct oxidative addition to a metal center. The low concentration of the reactive electrophile enables selective reaction with an arylcopper intermediate, rather than nucleophilic groups on the arylboronate, and binding of tert-butoxide to the boronate inhibits reaction of the electrophile with the tert-butoxide activator to form methyl ether.
- He, Zhi-Tao,Li, Haoquan,Haydl, Alexander M.,Whiteker, Gregory T.,Hartwig, John F.
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supporting information
p. 17197 - 17202
(2018/12/14)
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- Iridium-Catalyzed Asymmetric Hydrogenation of Benzo[b]thiophene 1,1-Dioxides
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An efficient iridium-catalyzed asymmetric hydrogenation of substituted benzothiophene 1,1-dioxides is described. The use of iridium complexes with chiral pyridyl phosphinite ligands provides access to highly enantiomerically enriched sulfones with substituents at the 2- and 3-position. Sulfones of this type are of interest as core structures of agrochemicals and pharmaceuticals. Moreover, they can be further reduced to chiral 2,3-dihydrobenzothiophenes.
- Tosatti, Paolo,Pfaltz, Andreas
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supporting information
p. 4579 - 4582
(2017/04/11)
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- Thieme Chemistry Journal Awardees - Where are They Now? The Influence of Electron-Withdrawing Groups at the 2- and 2′-Positions of Dibenzothienylethenes on Molecular Switching
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Three dibenzothienylethenes that carry a methyl, a trifluoromethyl, or a fluoro substituent in the 2- and 2′-position were synthesised in short multistep syntheses, respectively. The trifluoromethyl and fluoromethyl substituents significantly improve the absorption properties of the corresponding open and closed isomers (both in the UV-A and in the visible range). The increasing electron deficiency (i) enlarges the portion of the closed and coloured diarylethene isomer in the corresponding photostationary states and slows down the closing and opening isomerisation, (ii) the switching reactions, both closing and opening, are slowed down, and (iii) the switching quantum yields are lowered.
- Hofs?β, Robert,Rombach, David,Wagenknecht, Hans-Achim
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p. 1422 - 1426
(2017/07/22)
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- Asymmetric octafluorocyclopentene compound with continuous selectivity for Hg2+ and Cys, preparation method and application thereof
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The invention discloses [1-[2-methyl-3-benzothiophene], 2-(2-methyl-5-(4-phenyl)-(2-benzoylquinoline-8-benzothiazolyl)-3-thienyl)] octafluorocyclopentene, a preparation method and an application thereof. The preparation method comprises the following steps: by taking benzothiophene as a raw material, replacing by methyl iodide and bromizing and then reacting with octafluorocyclopentene, thereby generating mono-substituted octafluorocyclopentene; by taking 2-thiotolene as a raw material, bromizing and causing n-butyllithium to react with tributyl borate; connecting aldehyde-terminated benzene with thiophene ring through Stuzki coupling; protecting by adopting ethylene glycol and then reacting with the mono-substituted octafluorocyclopentene; reducing into alcoholic hydroxyl group and becoming methylene-containing bromine; reacting with 8-hydroxyquinoline-2-aldehyde group; and finally reacting with 2-amino thiophenol, thereby acquiring a target compound. The compound prepared according to the invention can be used for continuously detecting specific ions and amino acid and has an excellent selectivity.
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Paragraph 0016; 0034; 0037
(2017/07/20)
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- Reversible Photomodulation of Electronic Communication in a π-Conjugated Photoswitch-Fluorophore Molecular Dyad
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The extent of electronic coupling between a boron dipyrromethene (BODIPY) fluorophore and a diarylethene (DAE) photoswitch has been modulated in a covalently linked molecular dyad by irradiation with either UV or visible light. In the open isomer, both moieties can be regarded as individual chromophores, while in the closed form the lowest electronic (S0→S1) transition of the dyad is slightly shifted, enabling photomodulation of its fluorescence. Transient spectroscopy confirms that the dyad behaves dramatically different in the two switching states: while in the open isomer it resembles an undisturbed BODIPY fluorophore, in the closed isomer no fluorescence occurs and instead a red-shifted DAE behavior prevails.
- Moreno, Javier,Schweigh?fer, Felix,Wachtveitl, Josef,Hecht, Stefan
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p. 1070 - 1075
(2016/01/16)
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- In vivo phenotypic drug discovery: Applying a behavioral assay to the discovery and optimization of novel antipsychotic agents
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Phenotypic drug discovery (PDD) is increasingly being recognized as a viable compliment to target-based drug discovery (TDD). By measuring functional changes, typically at a systems level, PDD can facilitate the identification of compounds having a desirable pharmacology. This capability is particularly important when studying CNS diseases where drug efficacy may require modulation of multiple targets in order to overcome a robust, adaptive biological system. Here, we report the application of a mouse-based high-dimensional behavioral assay to the discovery and optimization of a structurally and mechanistically novel antipsychotic. Lead optimization focused on optimizing complex behavioral features and no explicit effort was made to identify the target (or targets) involved.
- Shao, Liming,Campbell, Una C.,Fang, Q. Kevin,Powell, Noel A.,Campbell, John E.,Jones, Philip G.,Hanania, Taleen,Alexandrov, Vadim,Morganstern, Irene,Sabath, Emily,Zhong, Hua M.,Large, Thomas H.,Spear, Kerry L.
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supporting information
p. 1093 - 1101
(2016/07/06)
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- Cyclopenta[b]annulation of Heteroarenes by Organocatalytic γ′[C(sp3)?H] Functionalization of Ynones
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A new approach for the cyclopenta[b]annulation of heteroarenes through metal-free and directing-group-free γ′[C(sp3)?H] functionalization and intramolecular hydroalkylation of ynones has been developed. In an unprecedented event, nucleophilic addition of an organophosphine to the designed ynones triggers γ′[C(sp3)?H] functionalization, leading to the formation of heteroaryl-based ortho-quinodimethane (oQDM) intermediates that undergo carbocyclization to provide cyclopentannulated heteroarenes in good yields and excellent stereoselectivities. Deuterium-labeling experiments substantiated the proposed reaction mechanism as well as the speculated epimerization.
- Raghu, Moluguri,Grover, Jagdeep,Ramasastry
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supporting information
p. 18316 - 18321
(2016/12/16)
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- Photomobile polymer materials: Photoresponsive behavior of cross-linked liquid-crystalline polymers with mesomorphic diarylethenes
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Cross-linked liquid-crystalline (LC) polymers with a mesomorphic diarylethene were prepared to demonstrate a versatile strategy for cross-linked photochromic LC polymers as photomobile materials. Upon exposure to UV light to cause photocyclization of the diarylethene chromophore, the cross-linked polymer films bend toward an actinic light source. By irradiation with visible light to cause a closed-ring to open-ring isomerization, the bent films revert to the initial flat state. Without visible-light irradiation, the bent films remain bent even at 120 8C, indicating high thermal stability of the cross-linked diarylethene LC polymers.
- Mamiya, Jun-Ichi,Kuriyama, Akito,Yokota, Naoki,Yamada, Munenori,Ikeda, Tomiki
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supporting information
p. 3174 - 3177
(2015/03/05)
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- Substituent effects on the photochromic properties of benzothiophene-based derivatives
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Five diarylethene photochromic derivatives, the structures of which incorporate a central benzothiophene unit, a left-hand thiazole group, and a right-hand benzothiophene group, have been prepared. The compound with a thiazole unit with no substituent on the reaction-center carbon atom reveals an unprecedented transformation upon light irradiation. When the 4-position of thiazole is protected by a methyl group, the compounds show high photosensitivity and photochromic properties. In this case, light irradiation affords new compounds with [5]helicene structures featuring the highest redshifted absorption maxima reported to date.
- Galangau, Olivier,Nakashima, Takuyama,Maurel, Fran?ois,Kawai, Tsuyoshi
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supporting information
p. 8471 - 8482
(2015/06/02)
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- Lewis acid/Broensted acid mediated benz-annulation of thiophenes and electron-rich arenes
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A facile preparation of benz-annulated heterocycles were achieved at rt involving a Lewis acid/Broensted acid mediated annulation of heterocycles using 2,5-dimethoxytetrahydrofuran as a four-carbon synthon. The benz-/naphth-annulation was found to be successful with electron-rich arenes as well.
- Rafiq, Settu Muhamad,Sivasakthikumaran, Ramakrishnan,Mohanakrishnan, Arasambattu K.
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supporting information
p. 2720 - 2723
(2014/06/09)
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- Copper-catalyzed synthesis of benzo[ b ]thiophenes and benzothiazoles using thiocarboxylic acids as a coupling partner
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An efficient copper-catalyzed approach to benzo[b]thiophene and benzothiazole derivatives using thiocarboxylic acids as a sulfur source has been developed. In the presence of CuI and 1,10-phen, and n-Pr3N as the base, (2-iodobenzyl)triphenylphosphonium bromide and (2-iodophenylimino) triphenylphosphorane reacted smoothly with thiocarboxylic acids to give benzo[b]thiophene and benzothiazole derivatives in good yields via sequential Ullmann-type C-S bond coupling and Wittig condensation.
- Yu, Hui,Zhang, Meishu,Li, Yuzhe
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p. 8898 - 8903
(2013/09/24)
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- Nickel-catalyzed hydrogenolysis of unactivated carbon-cyano bonds
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Selective hydrogenolysis of C-CN bonds can allow chemists to take advantage of ortho-directing ability, α-C-H acidity and electron withdrawing ability of the cyano group for synthetic manipulations. We have discovered hydrogenolysis of aryl and aliphatic cyanides under just 1 bar of hydrogen by using a nickel catalyst. This protocol was applied in the aryl cyanide directed functionalization reaction and α-substitution of benzyl cyanides.
- Patra, Tuhin,Agasti, Soumitra,Modak, Atanu,Maiti, Debabrata
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supporting information
p. 8362 - 8364
(2013/09/23)
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- Asymmetric hydrogenation of thiophenes and benzothiophenes
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An efficient and highly asymmetric ruthenium-N-heterocyclic carbene-catalyzed hydrogenation of substituted thiophenes and benzothiophenes is described, providing a new strategy for the formation of valuable enantiomerically pure tetrahydrothiophenes and 2,3-dihydrobenzothiophenes.
- Urban, Slawomir,Beiring, Bernhard,Ortega, Nuria,Paul, Daniel,Glorius, Frank
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supporting information
p. 15241 - 15244
(2012/11/07)
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- Synthesis and photochromism of functionalized benzothiophene-based fulgides and fulgimides
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Earlier unknown fulgides and the corresponding functionalized fulgimides containing a primary amino group were obtained. Their photochromism was examined using spectroscopic methods.
- Luyksaar,Migulin,Nabatov,Krayushkin
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body text
p. 446 - 451
(2011/02/17)
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- Photochromic amorphous molecular materials based on dibenzothienylthiazole structure
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Terarylene derivatives having benzothienyl moieties, 4,5-bis(2- methylbenzo[b]thiophene-3-yl)-2-phenylthiazole, 4,5-di(benzo[b]thiophen-3-yl)-2- phenylthiazole are synthesized and their photochromic properties are studied. These photochromic molecules show fairly high photoreactivities in both solution and bulk amorphous film, and show relatively high glass-transition temperatures. The former molecule shows photochromic reactivity even in the single crystalline phase.
- Kawai, Shigekazu,Nakashima, Takuya,Kutsunugi, Yuuichirou,Nakagawa, Hisako,Nakano, Hideyuki,Kawai, Tsuyoshi
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supporting information; experimental part
p. 3606 - 3611
(2010/06/16)
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- Photochromic properties of terarylene derivatives having a π-conjugation unit on central aromatic ring
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A series of terarylenes based on 4,5-bisbenzothienylthiazole have been synthesized, and their photochromic properties are studied both in solution and in the crystalline state. The substitution effect of the central aromatic ring on the photochromic reactivity were also studied. The introduction and expansion of the π-conjugated system at the 2-position of the thiazole ring led to a red-shift of the absorption peaks for both open- and closed-ring isomers of terarylenes. 2-Hydro and 2-phenyl derivatives of 4,5-bisbenzothienylthiazoles displayed a photochromic reaction, even in the single-crystal state. X-Ray crystal analysis showed their molecular structure to have quasi-C2 symmetry, suggesting significant CH...N and CH...S interactions. Although the 2-hydro and 2-phenyl derivatives exhibited high photocyclization reaction quantum yields over 0.5, the 2-phenylthienyl derivative showed a considerably smaller reactivity, even though it is supposed to have a similar conformation to those of the other two derivatives. Meanwhile, these molecules showed similar photocycloreversion quantum yields as high as 0.3. The relationship between their electronic structures and photochromic reactivity is also discussed by means of quantum chemical calculations. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2009.
- Kutsunugi, Yuichiro,Kawai, Shigekazu,Nakashima, Takuya,Kawai, Tsuyoshi
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experimental part
p. 1368 - 1373
(2009/09/24)
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- Cycloaddition of thiophene S-oxides to allenes, alkynes and to benzyne
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Thiophenes have been treated with alkynes in the presence of m-chloroperoxybenzoic acid to give substituted arenes as cycloadducts. Alternatively, thiophene S-oxides have been prepared by oxidation from thiophenes and have been subjected to cycloaddition with alkynes in a subsequent step. The outcome of the reaction is dependent on the steric demand of the thiophene S-oxide. Some thiophene S-oxides can be reacted at temperatures as high as 140°C without decomposition. Thiophenes as deoxygenated products are the main by-products. Reactions of thiophene S-oxides with allenes give in part thiabicyclo[2.2.1]heptene S-oxides of type 12a and 13 along with aromatized products. Thiophene S-oxides also cycloadd to benzyne.
- Thiemann, Thies,Fujii, Hideki,Ohira, Daisuke,Arima, Kazuya,Li, Yuanqiang,Mataka, Shuntaro
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p. 1377 - 1384
(2007/10/03)
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- Biphenylsulfonamides and derivatives thereof that modulate the activity of endothelin
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Biphenylsulfonamides and methods for modulating or altering the activity of the endothelin family of peptides are provided. In particular, bicyclic or tricyclic carbon or heterocyclic ring biphenylsulfonamides and methods using these sulfonamides for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.
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- N-aryl thienyl-, furyl-, and pyrrolyl-sulfonamides and derivatives thereof that modulate the activity of endothelin
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Thienyl-, furyl- and pyrrolyl-sulfonamides and methods for modulating or altering the activity of the endothelin family of peptides are provided. In particular, N-(isoxazolyl)thienylsulfonamides, N-(isoxazolyl)furylsulfonamides and N-(isoxazolyl)pyrrolylsulfonamides and methods using these sulfonamides for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.
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Page column 64
(2010/01/30)
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- A convenient one-pot preparation of benzo[b] -tellurophenes, - selenophenes, and -thiophenes from o- bromoethynylben zenes
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2-Substituted and unsubstituted benzo[b]tellurophenes (3Aa-e) were synthesized in one-pot from o-bromoethynylbenzenes (2) via three steps in good yields. Similarly, benzo[b]-selenophenes (3Ba-e) and -thiophenes (3Ca- e) were also obtained.
- Sashida, Haruki,Sadamori, Kunio,Tsuchiya, Takashi
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p. 713 - 727
(2007/10/03)
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- Phenyl migration to thiophene ring in photolysis of 1-phenylbenzo[b]thiophenium salts
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Photolysis of 1-phenylbenzo[b]thiophenium salts was conducted by use of a Pyrex-filtered high pressure Hg lamp. The major products in most cases were the phenyl-migrated ones, i.e., 2-phenylbenzo[b]thiophenes and 3-phenylbenzo[b]thiophenes, together with the dephenylated benzo[b]thiophenes. This photochemical behavior is quite different from the thermal ones that provide the ring-opened olefins. The selective phenyl migration to the thiophene ring and the absence of the ionic products are characteristic of benzothiophenium systems.
- Kitamura, Tsugio,Morizane, Kunihiko,Taniguchi, Hiroshi,Fujiwara, Yuzo
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p. 5157 - 5160
(2007/10/03)
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- THIENYL-, FURYL- AND PYRROLYL SULFONAMIDES AND DERIVATIVES THEREOF THAT MODULATE THE ACTIVITY OF ENDOTHELIN
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Thienyl-, furyl-and pyrrolyl-sulfonamides and methods for modulating or altering the activity of the endothelin family of peptides are provided. In particular, N-(isoxazolyl)thienylsulfonamides, N-(isoxazolyl) furylsulfonamides and N-(isoxazolyl)pyrrolylsulfonamides and methods using these sulfonamides for inhibiting the binding of an endothelin peptide to an endothelin receptor by contacting the receptor with the sulfonamide are provided. Methods for treating endothelin-mediated disorders by administering effective amounts of one or more of these sulfonamides or prodrugs thereof that inhibit or increase the activity of endothelin are also provided.
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- Benzothiophene/indole-substituted maleimide derivatives, photochromic material comprising said derivatives and optical recording material using the same material
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A novel benzothiophene/indole-substituted maleimide derivative, a photochromic material and an optical recording material using the same. The benzothiophene/indole-substituted maleimide derivative is represented by the following formula (1): STR1 or the following formula (2): STR2 wherein R is a substituted or an unsubstituted monovalent hydrocarbon group, R1 and R2 are a hydrogen atom, an alkyl group, an alkylthio group or an alkoxy group under the condition where at least either one of them is an alkylthio group or an alkoxy group, R3 is an alkyl group or an acyl group, and rings A and B may not be substituted or may be substituted with an alkyl group, an alkoxy group or a halogen atom, respectively.
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- Electrophilic Reactions of Carbenoids. Synthesis of Fused Heterocyclic Systems via Intramolecular Nucleophilic Substitution of Carbenoids
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Intramolecular nucleophilic substitution of carbenoids with oxygen, nitrogen, and sulfur nucleophiles leading to the synthesis of fused heterocyclic compounds has been studied.For the purpose of this investigation styryl type gem-dihalides 4, 8, 18, 20, 28 containing a nucleophilic substituent in the ortho position of the aromatic ring have been synthesized.Carbenoids have been generated in those systems by the halogen - metal exchange reaction and shown to readily undergo intramolecular nucleophilic substitution by the properly located nucleophilic group (OH, SH, or NH2).As a result a new synthetic route to benzofurans, thianaphthenes, and indoles has been established based on nucleophilic substitution of vinyl halides by an ortho substituent.The dramatic increase of reactivity of vinyl halides upon introduction of lithium has been explained as being due to metal-assisted ionization.
- Topolski, Marek
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p. 5588 - 5594
(2007/10/03)
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- Flash Vacuum Pyrolysis of Stabilised Phosphorous Ylides. Part 3. Preparation of o-Methoxyphenyl- and o-Methylsulfanylphenyl-alkynes and their Cyclisation to Benzofuranes and Benzothiophenes
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Fourteen new β-oxo phosphorus ylides 1 - 14 bearing o-methoxybenzoyl or o-(methylsulfanyl)benzoyl groups have been prepared and their pyrolytic behaviour studied.While flash vacuum pyrolysis (FVP) at 700 deg C brings about extrusion of Ph3PO to give the expected alkynes 16, this is accompained at 850 deg C by loss of Me* and cyclisation of the resulting radicals to afford 2-substituted benzofurans or benzothiophenes 17 - 24.Where the substituent R1 on the ylidic carbon of the starting material is phenyl, this is incorporated unchanged into the heterocyclic products.Where R1 is Et or Pri the vinyl products are formed by intramolecular abstraction of a β-hydrogen atom following cyclisation.For R1 = Me, Pr, Bu, and C5H11 the cyclisation is followed by hydrogen atom abstraction from the alkyl group leading to its fragmentation and giving products with 2-methyl, ethyl and vinyl substituents.In these cases the products can be accounted for by a radical chain reaction involving the unusual homolytic substitution of a carbon radical at a saturated carbon atom.
- Aitken, R. Alan,Burns, Graham
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p. 2455 - 2460
(2007/10/02)
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- Molecular recognition in aqueous media. new binding studies provide further insights into the cation-π interaction and related phenomena
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We describe a large number of binding studies in aqueous media designed to provide new insights into noncovalent binding interactions, especially the cation-π interaction. The studies include 7 different hosts, over 70 guests, and over 150 new binding constants. In addition to the now standard NMR methods, circular dichroism has proven to be an especially useful tool for determining aqueous binding constants. We have found that, in addition to the alkyliminium and tetraalkylammonium guests we have studied previously, sulfonium and guanidinium guests also show substantial cation-π effects. Bromination of the host greatly enhances its binding ability in a general fashion, primarily as a result of hydrophobic interactions. Addition of methoxy groups did not enhance binding, apparently as a result of a collapse of the host into a conformation that is not suitable for binding. Replacement of two benzene rings of the host by furans or thiophenes also did not enhance binding. Ab initio calculations provide a rationalization for this effect and suggest a clearer model for the cation-π interaction.
- Kearney, Patrick C.,Mizoue, Laura S.,Kumpf, Robert A.,Forman, Jonathan E.,McCurdy, Alison,Dougherty, Dennis A.
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p. 9907 - 9919
(2007/10/02)
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- The Claisen Rearrangement of 2-Phenylsulfinyl-2-propenyl Phenyl Ethers - A New Route to Functionalized Phenols and 2-Methylbenzofurans
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The hitherto unknown Claisen rearrangement of 2-phenylsulfinyl-2-propenyl phenyl ethers to the corresponding 2-(2-phenylsulfinyl-2-propenyl)phenols is reported.The latter compounds underwent Michael reactions with a variety of nucleophiles to provide functionalized phenolic adducts.O-Alkylation of the initial rearrangement products with 3-bromo-2-phenylsulfinyl-1-propene and 2,3-dibromo-1-propene followed by sigmatropic rearrangement provided a promising route to 7-substituted 2-methylbenzofurans.
- Khan, Muhammad Akram
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p. 3682 - 3686
(2007/10/02)
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- Thiophenes as Traps for Benzyne. 2. Cycloadditions and Ene Reactions
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The reactions of 11 mono- and disubstituted thiophenes (1b-1l) with benzyne generated from diphenyliodonium 2-carboxylate (7) were studied under a standard set of conditions.The major products were naphthalenes (3) whose substitution patterns indicated that both and cycloaddition occurred, with the former predominating.A significant proportion of cycloaddition was found only with the 3-halothiophenes 1i and 1k, suggesting enamine-like enhancement of the 2?-character of the thiophene.Benzothiophenes (8) were found in low yields in several of the reactions, and their substitution patterns suggested a cycloaddition mechanism involving an intermediate betaine 11.Ene (17) and especially double ene (18) products were observed with the alkylthiophenes 1b-d and 1g.The halothiophenes 1h-l underwent substantial carbon-halogen bond cleavage leading to halogenated phenylthiophenes.
- Reinecke, Manfred G.,Mazza, Dario Del
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p. 2142 - 2146
(2007/10/02)
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- Analgesic carbocyclic and heterocyclic carbonylmethylene-and carbonylmethypipidines and-pyrrolidines
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Carbocyclic and heterocyclic carbonylmethylene- and carbonylmethylpiperidines and -pyrrolidines are serotonin antagonists.
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- Preparation and Chemical Behaviour of exo-Methylene Compounds: Isoelectronic Compounds of 5-Methylenecyclohexa-1,3-diene
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Some exo-methylene compounds such as 9-methylene-9,10-dihydrophenanthrene(2) were photolytically prepared and their chemical behaviour was investigated.Treatment of (2) with acid (CF3CO2H) or base (OBut(1-)) led to the formation of 9-methylphenanthrene, with bromine to 9-bromomethylphenanthrene.Reaction with dimethyl acetylenedicarboxylate did not give Diels-Alder adduct but give an ene adduct.Treatment with ethenetetracarbonitrile also gave an ene adduct.Reaction with carbene or carbenoids gave 9,10-dihydrophenanthrene-9-spirocyclopropanes.Reaction with ethenetetracarbonitrile was examined for other exo-methylene compounds, 1-methylene-1,2-dihydronaphtalene and 2-methylene-2,3-dihydrobenzothiophene.The aromatisation may be responsible for the reactions of these exo-methylene compounds except for the reaction with carbenes.
- Sugimoto, Akira,Yamano, Junzo,Yasueda, Masahiro,Yoneda, Shigeo
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p. 2579 - 2584
(2007/10/02)
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- A Facile Route to 4,5,6,7-Tetrahydrothiophenes and Benzothiophenes
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2-Substituted tetrahydro- and cyclopentathiophenes 2 were produced in high yields by treatment of the semi-cyclic trisubstituted 1,4-diketones 1 such as 2-phenacylcyclohexan-1-one, 2-acetonylcyclohexan-1-one, and 2-phenacylcyclopentan-1-one, with Lawesson's reagent.
- Nishio, Takehiko,Okuda, Norikazu,Kashima, Choji
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p. 1437 - 1438
(2007/10/02)
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- A NEW SYNTHESIS OF 2-SUBSTITUTED BENZOFURANS AND BENZOTHIOPHENS: NOVEL FRAGMENTATION REACTIONS OF SIMPLE ALKYL GROUPS
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Flash vacuum pyrolysis of (2-methoxy- and (2-methylthiobenzoyl)alkylidenetriphenylphosphoranes results in loss of Ph3PO and methyl radical; cyclisation of the resulting radical intermediates leads to benzofurans and benzothiophens in which the 2-substituents have undergone novel fragmentation processes.
- Aitken, R. Alan,Burns, Graham
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p. 3717 - 3718
(2007/10/02)
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