- Chiral photoresponsive tetrathiazoles that provide snapshots of folding states
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Herein, we designed chiral photoresponsive tetra(2-phenylthiazole)s, which induce a diastereoselective 6π-electrocyclization reaction in a helically folded structure to freeze the conformational interconversions. The folding conformation with one helical
- Nakashima, Takuya,Yamamoto, Kyohei,Kimura, Yuka,Kawai, Tsuyoshi
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Read Online
- Development of Red-Shifted and Fluorogenic Nucleoside and Oligonucleotide Diarylethene Photoswitches
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The reversible modulation of fluorescence signals by light is of high interest for applications in super-resolution microscopy, especially on the DNA level. In this article we describe the systematic variation of the core structure in nucleoside-based diarylethenes (DAEs), in order to generate intrinsically fluorescent photochromes. The introduction of aromatic bridging units resulted in a bathochromic shift of the visible absorption maximum of the closed-ring form, but caused reduced thermal stability and switching efficiency. The replacement of the thiophene aryl unit by thiazol improved the thermal stability, whereas the introduction of a benzothiophene unit led to inherent and modulatable turn-off fluorescence. This feature was further optimized by introducing a fluorescent indole nucleobase into the DAE core, resulting in an effective photoswitch with a fluorescence quantum yield of 0.0166 and a fluorescence turn-off factor of 3.2. The site-specific incorporation into an oligonucleotide resulted in fluorescence-switchable DNA with high cyclization quantum yields and switching efficiency, which may facilitate future applications.
- Kolmar, Theresa,Becker, Antonia,Pfretzschner, Ronja A.,Lelke, Alina,J?schke, Andres
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supporting information
p. 17386 - 17394
(2021/10/20)
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- NOVEL COMPOUND, PHOTOACID GENERATOR CONTAINING THE COMPOUND, AND PHOTOSENSITIVE RESIN COMPOSITION CONTAINING THE PHOTOACID GENERATOR
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PROBLEM TO BE SOLVED: To provide a nonionic photoacid generator with high acid generation quantum yield. SOLUTION: The present invention provides a compound represented by formula (2) (where, ring Ar is a benzene ring, naphthalene ring, thiophene ring or
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Paragraph 0074; 0075
(2018/12/05)
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- Light-controlled reversible modulation of frontier molecular orbital energy levels in trifluoromethylated diarylethenes
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Among bistable photochromic molecules, diarylethenes (DAEs) possess the distinct feature that upon photoisomerization they undergo a large modulation of their pelectronic system, accompanied by a marked shift of the HOMO/LUMO energies and hence oxidation/
- Herder, Martin,Eisenreich, Fabian,Bonasera, Aurelio,Grafl, Anna,Grubert, Lutz,P?tzel, Michael,Schwarz, Jutta,Hecht, Stefan
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supporting information
p. 3743 - 3754
(2017/03/21)
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- A self-contained photoacid generator for super acid based on photochromic terarylene
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A self-contained photoacid generator for super acid along with the photoinduced 6π-electrocyclization reaction of the terarylene backbone is demonstrated. The photoinitiated cationic polymerization of epoxy-monomers is achieved with an efficient photochem
- Li, Ruiji,Nakashima, Takuya,Kawai, Tsuyoshi
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supporting information
p. 4339 - 4341
(2017/04/21)
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- Photoswitching of an intramolecular chiral stack in a helical tetrathiazole
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On-off photoswitching of circularly polarized luminescence was achieved using a pyrene-bearing helical tetrathiazole, in which two pyrene fluorophores stack in a chiral fashion (folded state). The pyrene-excimer based CPL was reversibly controlled by a ge
- Hashimoto, Yuichiro,Nakashima, Takuya,Shimizu, Daiya,Kawai, Tsuyoshi
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supporting information
p. 5171 - 5174
(2016/04/26)
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- Photon-Quantitative 6π-Electrocyclization of a Diarylbenzo[b]thiophene in Polar Medium
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The high reactivity of 6π-electrocyclization in polar solvents has remained one of the important challenges for diarylethenes because of the emergence of a twisted intramolecular charge transfer (TICT) state at the excited state in such polar media, which usually quenches the photocyclization reaction. Herein we report on the preparation and highly efficient photocyclization of 2,3-diarylbenzo[b]thiophenes with nonsymmetric side-aryl units in a polar solvent. While the dithiazolylbenzo[b]thiophene showed a suppressed quantum yield of 6π-electrocyclization of 54% in methanol, the replacement of a thiazole unit with a thiophene ring led to a photon-quantitative 6π-cyclization reaction. The nonsymmetrical modification into the side-aryl units was considered to enhance the CH/π interactions between side-aryl units to support a photoreactive conformation in methanol. The stabilization of the photochromic reactive conformation is expected to suppress the formation of the TICT state at the excited state, leading to highly efficient photoreactivity.
- Li, Ruiji,Nakashima, Takuya,Galangau, Olivier,Iijima, Shunsuke,Kanazawa, Rui,Kawai, Tsuyoshi
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supporting information
p. 1725 - 1730
(2015/08/06)
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- DIARYLETHENE COMPOUNDS AND USES THEREOF
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A compound according to Formula IA and IB, reversibly convertible under photochromic and electrochromic conditions between a ring-open isomer A and a ring-closed isomer B is provided. For substitutent groups, Z is N, O or S; each R1 is independently selected from the group consisting of H, or halo; each R2 is independently selected from the group consisting of H, halo, a polymer backbone, alkyl or aryl; or, when both R2 together form —CH═CH— and form part of a polymer backbone; each R3 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl; each R4 is aryl; and each R5 is independently selected from the group consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl.
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Paragraph 0251
(2014/09/29)
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- Highly flexible π-expanded cyclooctatetraenes: Cyclic thiazole tetramers with head-to-tail connection
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Flipping fast: Head-to-tail cyclic thiazole tetramers representing flexible π-expanded cyclooctatetraenes were designed and synthesized (see picture). The presence of fused thiazole rings in a head-to-tail arrangement leads to a strong columnar stacking of the shallow saddle-shaped π-conjugated molecules, an unusually low inversion barrier of 6.8kcal mol-1, and reduction-induced complete planarization to an aromatic ring system. Copyright
- Mouri, Kazuhiro,Saito, Shohei,Yamaguchi, Shigehiro
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supporting information; experimental part
p. 5971 - 5975
(2012/07/30)
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- A guideline for the arylation of positions 4 and 5 of thiazole via Pd-catalyzed cross-coupling reactions
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The arylation of thiazoles in 4- and 5-position was investigated in detail. Suzuki-Miyaura and Stille cross-coupling reactions were tested using thiazoles either as halide or organometal species. The obtained results were critically compared to develop he
- H?mmerle, Johanna,Schnürch, Michael,Iqbal, Naseer,Mihovilovic, Marko D.,Stanetty, Peter
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scheme or table
p. 8051 - 8059
(2010/10/21)
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- Catalyst-controlled regioselective suzuki couplings at both positions of dihaloimidazoles, dihalooxazoles, and dihalothiazoles
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(Chemical Equation Presentation) Various dihaloazoles can be monoarylated at a single C-X bond with high selectivity via Suzuki coupling. By changing the palladium catalyst employed, the selectivity can be switched for some dihaloazoles, allowing for Suzuki coupling at the other, traditionally less reactive C-X bond. These conditions are applicable to coupling of a wide variety of aryl-, heteroaryl-, cyclopropyl-, and vinylboronic acids with high selectivities and enable the rapid construction of diverse arrays of diarylazoles in a modular fashion.
- Strotman, Neil A.,Chobanian, Harry R.,He, Jiafang,Guo, Yan,Dormer, Peter G.,Jones, Christina M.,Steves, Janelle E.
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supporting information; experimental part
p. 1733 - 1739
(2010/05/18)
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- A comparative study on stille cross-coupling reactions of 2-phenylthiazoles and 2-phenyloxazoles
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A systematic study of the cross-coupling capability of the 4- and 5-positions of 2-phenylthiazoles and -oxazoles under Stille conditions is presented. The azoles were both applied as stannanes and as the halide component. The obtained results were compared regarding the position of the halide and Bu3Sn group. In order to establish a general reactivity platform for those heterocyclic systems, a broad variety of aromatic and heteroaromatic halides were coupled and some significant differences concerning the coupling properties of the investigated systems were observed. Georg Thieme Verlag Stuttgart.
- Haemmerle, Johanna,Spina, Markus,Schnuerch, Michael,Mihovilovic, Marko D.,Stanetty, Peter
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scheme or table
p. 3099 - 3107
(2009/04/06)
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- Comparing the reactivity of the 4- and 5-positions of 2-phenylthiazoles in stille cross-coupling reactions
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A systematic study of the cross-coupling capability of 4-and 5-substituted 2-phenylthiazoles under Stille conditions is presented. Two cross-coupling options were investigated: 1) combination of thiazolylstannanes with various aryl(hetaryl) halides and, 2) reaction of halothiazoles with PhSn(Bu) 3 as coupling partner. The results obtained from the cross-coupling reactions on the 4- and 5-positions of the thiazole system were compared regarding the influence of the position of the halide (Br, I) and the Bu 3Sn group on both coupling partners. A broad selection of aromatic and heteroaromatic halides was coupled in order to establish a general reactivity platform for this heterocyclic system. Georg Thieme Verlag Stuttgart.
- H?mmerle, Johanna,Schnürch, Michael,Stanetty, Peter
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p. 2975 - 2978
(2008/03/12)
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- Substituted diazabicycloalkane derivatives
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Compounds of formula (I) [in-line-formulae]Z-Ar1—Ar2??(I) [/in-line-formulae] wherein Z is a diazabicyclic amine, Ar1 is a 5- or 6-membered aromatic ring, and Ar2 is selected from the group consisting of an unsubstituted or substituted 5- or 6-membered heteroaryl ring; unsubstituted or substituted bicyclic heteroaryl ring; 3,4-(methylenedioxy)phenyl; carbazolyl; tetrahydrocarbazolyl; naphthyl; and phenyl; wherein the phenyl is substituted with 0, 1, 2, or 3 substituents in the meta- or para-positions. The compounds are useful in treating conditions or disorders prevented by or ameliorated by α7 nAChR ligands. Also disclosed are pharmaceutical compositions comprising compounds of formula (I) and methods for using such compounds and compositions.
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Page/Page column 69
(2010/02/11)
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- General facile synthesis of 2,5-diarylheteropentalenes
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Palladium-catalyzed cross-coupling reactions of various heteropentalene derivatives were systematically studied. A general three-step synthesis of 2,5-diarylheteropentalenes involving two Suzuki or Negishi couplings and a regiospecific bromination was developed. Nonsymmetrical 2,5-diaryl-furans, thiophenes, pyrroles, 1,3-thiazoles, 1,3-oxazoles, 1,3,4-thiadiazoles, and 1,3,4-oxadiazoles were prepared in 31-67% isolated yield (three steps).
- Vachal, Petr,Toth, Leslie M.
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p. 7157 - 7161
(2007/10/03)
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- New Methods for the Introduction of Substituents into Thiazoles
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New methods for the regioselective introduction of substituents into thiazoles have been developed using thiazole, 2-phenylthiazole and 4,5-dimethylthiazole as representative thiazoles.Improved halogenation methods, displacement of hydroxy groups in combination with dehalogenation at C-5 yield all eight possible 2-phenyl-4-halo-, 5-halo and 4,5-dihalo-thiazoles in which halogen is chlorine and bromine.Peracid oxidation of the thiazoles gives the corresponding thiazole 3-oxides.These are not activated towards halogenation but are deprotonated with sodium hydride.The anion formed react with electrophiles such as paraformaldehyde, 2,2-dimethylpropanal, 2,2-dimethylpropanoyl chloride, hexachloroethane, tetrabromomethane, and dimethyl disulfide leading to the introduction of carbon substituents, halogen, and methylthio groups.In these reactions, the reactivity of the thiazole ring positions decreases in the order 2 than 5 than 4.Monoselectivity is low when halogen and methylthio groups are introduced since these substituents enhance the acidity of adjacent ring protons. 2-Phenyl-4,5-dihalothiazole 3-oxides lose the 5-halogen when treated with sulfite ion.Trimethyloxonium tetrafluoroborate O-methylates thiazole 3-oxides.Thiazole N-oxides also react with acetyl chloride and phosphorus oxychloride to afford chlorothiazoles in a non-selective manner.Phosphorus trichloride deoxygenates thiazole 3-oxides.
- Begtrup, Mikael,Hansen, Lars Bo L.
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p. 372 - 383
(2007/10/02)
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