- Direct iodination of electron-deficient benzothiazoles: Rapid access to two-photon absorbing fluorophores with quadrupolar D-π-A-π-D architecture and tunable heteroaromatic core
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Direct iodination of benzothiazoles under strong oxidative/acidic conditions leads to a mixture of iodinated heteroarenes with 1-2 major components, which are easily separable and which structures depend on the I2 equivalents used. Among the unexpected bu
- Fakis, Mihalis,Georgiou, Dimitris,Hrobárik, Peter,Nociarová, Jela,Osusky, Patrik,Polyzos, Ioannis,Rakovsky, Erik
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supporting information
p. 3460 - 3465
(2021/05/31)
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- RADIOACTIVE IODINE LABELED STYRYL SUBSTITUTED AROMATIC HETEROCYCLIC COMPOUND
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PROBLEM TO BE SOLVED: To provide a novel tau protein imaging agent that allows imaging of biological tau protein by a noninvasive, nuclear medical method. SOLUTION: The present invention provides a radioactive iodine labeled styryl substituted aromatic heterocyclic compound represented by a predetermined general formula or a salt thereof, or a radioactive medicine comprising the same. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0060
(2016/11/21)
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- Structure-Activity Relationship Study of Heterocyclic Phenylethenyl and Pyridinylethenyl Derivatives as Tau-Imaging Agents That Selectively Detect Neurofibrillary Tangles in Alzheimers Disease Brains
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In order to explore novel tau-imaging agents that can selectively detect neurofibrillary tangles in Alzheimers disease (AD) brains, we designed and synthesized a series of heterocyclic phenylethenyl and (3-pyridinyl)ethenyl derivatives with or without a dimethyl amino group. In in vitro autoradiography using AD brain sections, all radioiodinated ligands with a dimethyl amino group bound to Aβ deposits in the sections. In contrast, the ligands without a dimethyl amino group showed different patterns of radioactivity accumulation in the sections depending on the kind of heterocycle contained in their molecules. Particularly, a phenylethenyl benzimidazole derivative ([125I]64) showed marked radioactivity accumulation in the temporal lobe which corresponded with the distribution of tau deposits. [125I]64 also showed the most favorable pharmacokinetics in normal mouse brains (3.69 and 0.06% ID/g at 2 and 60 min postinjection, respectively) among all ligands in this study. Taken together, these results suggest that [123I]64 may be a new candidate tau-imaging agent.
- Matsumura, Kenji,Ono, Masahiro,Kitada, Ayane,Watanabe, Hiroyuki,Yoshimura, Masashi,Iikuni, Shimpei,Kimura, Hiroyuki,Okamoto, Yoko,Ihara, Masafumi,Saji, Hideo
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p. 7241 - 7257
(2015/10/05)
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- Radioactive iodine labeled compound, and, radioactive pharmaceutical containing the same (by machine translation)
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PROBLEM TO BE SOLVED: and compatibility and affinity for both amyloidosis acryloyldimethyltauric, labeled compd. radioactive iodine. SOLUTION: the present invention, N, N-labeled compd. dimethyl benzene amine including radioactive iodine or its salt. Selected drawing: no (by machine translation)
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Paragraph 016; 0037; 0043; 0045
(2018/10/10)
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- Synthesis and characterization of near-infrared absorbing water soluble squaraines and study of their photodynamic effects in DLA live cells
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Here, we report the synthesis, photophysical properties and photodynamic effects in DLA live cells of three water soluble squaraine dyes, viz. bisbenzothiazolium squaraine dyes SQMI and SQDI with iodine in one and both benzothiazolium units, respectively, and an unsymmetrical squaraine dye ASQI containing iodinated benzothiazolium and aniline substituents. The diiodinated SQDI showed an anomalous trend in both fluorescence and triplet quantum yields over the monoiodinated SQMI, with SQDI showing higher fluorescence and lower triplet quantum yields compared to SQMI. Nanosecond laser flash photolysis of SQDI and SQMI indicated the formation of triplet excited states with quantum yield of 0.19 and 0.26, respectively. On photoirradiation, both the SQDI and SQMI generate singlet oxygen and it was observed that both dyes undergoing oxidation reactions with the singlet oxygen generated. ASQI which exhibited a lower triplet quantum yield of 0.06 was, however, stable and did not react with the singlet oxygen generated. In vitro cytotoxicity studies of these dyes in DLA live cells were performed using Trypan blue dye exclusion method and it reflect an order of cytotoxicity of SQDI>SQMI>ASQI. Intracellular generation of the ROS was confirmed by dichlorofluorescein assay after the in vitro PDT. Synthesis, photophysical properties and photodynamic effects in DLA live cells of three water soluble squaraine dyes, SQDI, SQMI and ASQI, are presented. On photoirradiation, both the SQDI and SQMI generate singlet oxygen where both the dyes undergoing oxidation reactions with the singlet oxygen generated, whereas ASQI was stable and did not react with the singlet oxygen. In vitro cytotoxicity studies of these dyes in DLA cells were performed using Trypan blue dye exclusion method and intracellular generation of ROS was confirmed using dichlorofluorescein assay after the in vitro PDT.
- Shafeekh, Kulathinte M.,Soumya, Mohanannair S.,Rahim, Moochikkadavath A.,Abraham, Annie,Das, Suresh
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p. 585 - 595
(2014/05/20)
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- Synthesis and photophysical properties of doubly porphyrin-substituted cyanine dye
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New porphyrin-(cyanine dye) composites, in which two porphyrins are bridged by a cyanine dye through triple bonds, were synthesized. In the UV-vis absorption spectra of the composites, the Soret band and Q-band were red-shifted to 436 and 575640 nm, respectively. The absorption originating from the cyanine dye portion was also red-shifted from 710 nm to 764 nm, suggesting the expansion of πconjugation over the porphyrin and cyanine dye parts. Fluorescence studies suggested that energy transfer from the porphyrin portion to the cyanine dye moiety occurred. The fluorescence intensity decreased with increasing dielectric constants of solvents, suggesting intramolecular photoinduced electron transfer from the porphyrin to the cyanine dye parts. The effective two-photon absorption (2PA) cross-section values were measured using a nanosecond open aperture Z-scan method. The maximum effective 2PA cross-section and two-photon excited fluorescence cross-section values were 33,000 GM and 4,800 GM, respectively, at 860 nm in toluene/pyridine (95:5).
- Ogawa, Kazuya,Nagatsuka, Yasunori,Kobuke, Yoshiaki
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experimental part
p. 678 - 685
(2012/07/14)
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- New pentacyclic ring systems: Intramolecular cyclization of o,o′-disubstituted bibenzothiazoles
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Efficient methods for the preparation of isomeric o,o′- diaminobibenzothiazoles (8a and 11a) and o,o′-diamino-2,2′- dimethylbibenzothiazoles (8b and 11b), potentially valuable building blocks for construction of hitherto unknown dithiazolo annulated pentacyclic heterocycles, have been developed. The dithiazolo annulated benzo[c]cinnolines 9a, 9b, and 12a were prepared from the corresponding diamines by oxidation with PhI(OAc) 2 in good yield. The dithiazolo annulated carbazoles 13 and 14 were efficiently prepared from the corresponding diamines by thermal cyclization in H3PO4. The unusual course of reduction and product formation of o,o′-dinitrosubstituted bibenzothiazoles 6a and 6b with SnCl2 under acidic conditions was rationalized by DFT quantum-mechanical calculations. It was suggested that cyclic products are formed from dinitroso derivatives and open-shell species immediately following on a reduction path.
- Racané, Livio,?i?ak, Helena,Mihali?, Zlatko,Karminski-Zamola, Grace,Trali?-Kulenovi?, Vesna
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experimental part
p. 2760 - 2767
(2011/04/27)
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- Benzothiazoles with tunable electron-withdrawing strength and reverse polarity: A route to triphenylamine-based chromophores with enhanced two-photon absorption
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A series of dipolar and octupolar triphenylamine-derived dyes containing a benzothiazole positioned in the matched or mismatched fashion have been designed and synthesized via palladium-catalyzed Sonogashira cross-coupling reactions. Linear and nonlinear optical properties of the designed molecules were tuned by an additional electron-withdrawing group (EWG) and by changing the relative positions of the donor and acceptor substituents on the heterocyclic ring. This allowed us to examine the effect of positional isomerism and extend the structure-property relationships useful in the engineering of novel heteroaromatic-based systems with enhanced two-photon absorption (TPA). The TPA cross-sections (δTPA) in the target compounds dramatically increased with the branching of the triphenylamine core and with the strength of the auxiliary acceptor. In addition, a change from the commonly used polarity in push-pull benzothiazoles to a reverse one has been revealed as a particularly useful strategy (regioisomeric control) for enhancing TPA cross-sections and shifting the absorption and emission maxima to longer wavelengths. The maximum TPA cross-sections of the star-shaped three-branched triphenylamines are ~500-2300 GM in the near-infrared region (740-810 nm); thereby the molecular weight normalized δTPA/MW values of the best performing dyes within the series (2.0-2.4 GM?g-1?mol) are comparable to those of the most efficient TPA chromophores reported to date. The large TPA cross-sections combined with high emission quantum yields and large Stokes shifts make these compounds excellent candidates for various TPA applications, including two-photon fluorescence microscopy.
- Hrobarik, Peter,Hrobarikova, Veronika,Sigmundova, Ivica,Zahradnik, Pavol,Fakis, Mihalis,Polyzos, Ioannis,Persephonis, Peter
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experimental part
p. 8726 - 8736
(2012/01/05)
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- Benzothiazole-based fluorophores of donor-π-acceptor-π-donor type displaying high two-photon absorption
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A series of novel heterocycle-based dyes with donor-π-bridge-acceptor- π-bridge-donor (D-π-A-π-D) structural motif, where benzothiazole serves as an electron-withdrawing core, have been designed and synthesized via palladium-catalyzed Sonogashira and Suzuki-type cross-coupling reactions. All the target chromophores show strong one-photon and two-photon excited emission. The maximum two-photon absorption (TPA) cross sections ΔTPA of the prepared derivatives bearing diphenylamino functionalities occur at wavelengths ranging from 760 to 800 nm and are as large as ~900-1100 GM. One- and two-photon absorption characteristics of the title dyes have also been investigated by using density functional theory (DFT) and the structure-property relationships are discussed. The TPA cross sections calculated by means of quadratic response time-dependent DFT using the Coulomb-attenuated CAM-B3LYP functional support the experimentally observed trends within the series, as well as higher ΔTPA values of the title compounds compared to those of analogous fluorene or carbazole-derived dyes. In contrast, the traditional B3LYP functional was not successful in predicting the observed trend of TPA cross sections for systems with different central cores. In general, structural modification of the π-bridge composition by replacement of ethynylene (alkyne) with E-ethenylene (alkene) linkages and/or replacement of dialkylamino electron-donating edge substituents by diarylamino ones results in an increase of ΔTPA values. The combination of large TPA cross sections and high emission quantum yields makes the title benzothiazole-based dyes attractive for applications involving two-photon excited fluorescence (TPEF).
- Hrobarikova, Veronika,Hrobarik, Peter,Gajdos, Peter,Fitilis, Ioannis,Fakis, Mihalis,Persephonis, Peter,Zahradnik, Pavol
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experimental part
p. 3053 - 3068
(2010/07/15)
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- Synthesis and photochemical evaluation of iodinated squarylium cyanine dyes
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Several (multiply) iodinated squarylium cyanine dyes of type 1 and 8 (see Scheme and Table), derived from 1,3-benzothiazole and 6-iodo-1,3-benzothiazole, were synthesized as potential new photosensitizers, with absorptions in the 700-nm region. Their ability to generate singlet oxygen (1O 2) was assessed by luminescence-decay measurement in the near-IR. Some of these new dyes show interesting photophysical properties, and may be potentially used in photodynamic therapy (PDT).
- Santos, Paulo F.,Reis, Lucinda V.,Duarte, Isabel,Serrano, Joao P.,Almeida, Paulo,Oliveira, Anabela S.,Ferreira, Luis F. Vieira
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p. 1135 - 1143
(2007/10/03)
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