- Recyclable copper-catalyzed cyclization of o-haloanilides and metal sulfides: An efficient and practical access to substituted benzothiazoles
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An efficient heterogeneous copper-catalyzed cyclization of o-haloanilides and metal sulfides has been achieved via the C–S coupling in DMF at 80 or 140 °C in the existence of an MCM-41-bound NHC-Cu(I) catalyst and then intramolecular condensation, delivering a wide range of substituted benzothiazoles in mostly good to high yields. This new MCM-41-NHC-CuI complex can facilely be obtained by a two-step procedure starting from easily accessible and inexpensive reagents and reused more than seven times without any significant loss of its catalytic efficiency. The present protocol has been successfully applied to the gram-scale synthesis of two antitumor agents 5F203 and PMX 610.
- Cai, Mingzhong,Hao, Wenyan,Huang, Wencheng,Ye, Qian
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- Benzothiazole-Schiff base-Tr*ger's base derivative and preparation method and application thereof
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The structural general formula of a benzothiazole-Schiff base-base derivative is shown as one of the following formulas, and the preparation method of the benzothiazole-Schiff base-base derivative comprises the following steps: selecting p-bromoaniline, paraformaldehyde, n-butyllithium, p-aminobenzoic acid, substituted o-phenylenediamine, benzothiazole and the like as raw materials, and performingmulti-step reaction to obtain the benzothiazole-Schiff base-base derivative. The product emits yellow green light, the Stokes shift is large, the product has obvious aggregation-induced emission, theexcellent solid-state luminescence performance and good thermal stability, and antifungal performance tests prove that part of the compounds have a good antibacterial effect.
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Paragraph 0047; 0056-0057; 0062-0063
(2020/08/02)
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- Eco-friendly syntheses of 2-substituted benzoxazoles and 2-substituted benzothiazoles from 2-aminophenols, 2-aminothiophenols and DMF derivatives in the presence of imidazolium chloride
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A simple, economical and metal-free approach to the synthesis of 2-substituted benzoxazoles and 2-substituted benzothiazoles from 2-aminophenols, 2-aminothiophenols and DMF derivatives, only using imidazolium chloride (50% mmol) as promoter without any other additive, was reported. Various 2-substituted benzoxazoles and 2-substituted benzothiazoles were thus prepared in moderate to excellent yields.
- Tian, Qingqiang,Luo, Wen,Gan, Zongjie,Li, Dan,Dai, Zeshu,Wang, Huajun,Wang, Xuetong,Yuan, Jianyong
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supporting information
(2019/01/21)
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- Synthesis method of 2-substituted benzoxazole, 2-substituted benzothiazole and derivatives thereof
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The invention provides a synthesis method of 2-substituted benzoxazole, 2-substituted benzothiazole and derivatives thereof. In the method, through ortho-aminophenol/2-aminothiophenol cyclization catalyzed by imidazole hydrochloride, synthesis of functionalized 2-substituted benzoxazole and 2-substituted benzothiazole is realized; the method is simple, economical and high in practicality. No othercatalysts or additives are used, the synthesis method ensures good functional group tolerance and excellent yield and purity, the reaction time is short, no harsh reaction conditions are needed, andthe method is suitable for industrial production.
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Paragraph 0047; 0052-0053
(2019/02/10)
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- Efficient CDI/CH3SO3H-catalyzed, microwave-assisted synthesis of 2-substituted benzothiazoles
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CDI combined with CH3SO3H was found to be highly effective for the cyclization of 2-aminothiophenol derivatives with carboxylic acids under MW condition. Fourteen benzothiazole derivatives were synthesized in good yield and their structures were characterized by1H-NMR,13C-NMR, IR and mass spectrometry. This simple, rapid synthetic method is believed to provide a useful process for the synthesis of 2-substituted benzothiazole compounds.
- Li, Yao-Wei,Zhang, Pei-Ming,Li, Rui,Bai, Yan,Yu, Yu,Gan, Zong-Jie
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supporting information
p. 34 - 39
(2019/05/04)
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- STYRYLBENZOTHIAZOLE DERIVATIVES AND USES IN IMAGING
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This disclosure relates to styrylbenzothiazole derivatives for use as in vivo imaging agents for the diagnosis of Parkinson's disease (PD) or other degenerative disorders or conditions of the central nervous system. Early diagnosis is particularly advantageous as neuroprotective treatment can be applied to healthy neural cells to delay or even prevent the onset of debilitating clinical symptoms.
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Page/Page column 6; 52
(2019/12/04)
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- Benzothiazole derivative NTNO and preparation method and application thereof
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The invention discloses a benzothiazole derivative NTNO, and a preparation method and application thereof. The derivative is specifically 6-(2-(6-nitrobenzothiazole-2-yl)-vinyl)naphthalen-2-ol (NTNO).The preparation method comprises the steps of dissolving 6-hydroxyl-2-naphthaldehyde and 2-methyl-6-nitrobenzothiazole in a small amount of ethanol, adding piperidine, and heating to allow reaction to obtain a crude product; after a solvent is removed from the crude product, performing silica-gel column separation to obtain a pure product. As a probe, NTNO does not fluoresce under acidic condition. With the rise of pH, new fluorescence emission at 526 nm appears and is gradually intensified. The pKa value is 7.85+/-0.022, the linear response range of the pH is 6.90-8.20, and monitoring of pH(6.8-7.4) change in a neutral cytoplasmic range is facilitated. In addition, the NTNO has the advantages of good OH selectivity, large Stokes shift and the like. Furthermore, the NTNO also has excellent cell membrane permeability and cytoplasmic staining ability and is suitable for the monitoring of pH changes within the cytoplasmic matrix range.
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Paragraph 0024-0027
(2019/03/08)
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- Design, synthesis and photophysical studies of styryl-based push-pull fluorophores with remarkable solvatofluorochromism
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A library of 20 styryl-based push-pull dyes derived from 6-amino substituted benzothiazoles were prepared by an efficient and practical synthetic route from low-cost starting materials. The dyes were firstly designed to present an effective anchoring site for subsequent conjugation. A series of aryl scaffolds, from substituted phenyl rings containing electron donating and withdrawing groups to polycyclic aromatic derivatives, were screened. The inductive effect of N-alkyl substituted benzothiazoles was also explored for three different arrangements. The investigation of the structure-photophysics relationship was performed by UV-vis absorption and steady-state fluorescence emission measurements in solution and by TD-DFT calculations. The dyes presented high brightness, absorption bands in the visible range (~370-453 nm) and large solvatofluorochromism comprising all the visible spectrum, as a consequence of the strong intramolecular charge transfer (ICT) nature of their excited state.
- Safir Filho, Mauro,Fiorucci, Sebastien,Martin, Anthony R.,Benhida, Rachid
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p. 13760 - 13772
(2017/11/27)
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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 of thiacyanine dyes containing coumarin moieties at benzothiazole rings
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New bischromophoric dyes (thiacarbocyanine and thiadicarbocyanine) containing coumarin moieties at each of the two benzothiazole systems, as well as monomethinecyanine containing coumarin moiety at only one heterocyclic system, manifest significant batho-chromic shift compared to relative coumarin-free dyes.
- Krasnaya, Zhanna A.,Kuz'Min, Vladimir A.,Litvinkova, Lyubov V.,Dorofeeva, Evgeniya O.,Zlotin, Sergei G.
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p. 212 - 214
(2013/09/02)
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- A new family of bioorthogonally applicable fluorogenic labels
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Synthetic procedures for the construction of fluorogenic azido-labels were developed. Photophysical properties were elaborated by experimental and theoretical investigations. Of the newly synthesized fluorogenic and bioorthogonally applicable dyes two were selected on the basis of their fluorogenic performance and further subjected to in vitro and in vivo studies. Both tags exhibited excellent fluorogenic properties as in aqueous medium, the azide form of the selected dyes is virtually non-fluorescent, while their "clicked" triazole congeners showed intense fluorescence. One of these labels showed a very large Stokes shift. To the best of our knowledge this is the first reported case of mega-Stokes type of fluorogenic labels. These studies have justified that these two fluorogenic tags are remarkably suitable for bioorthogonal tagging schemes. The developed synthetic approach together with the theoretical screen of possible fluorogenic tags will enable the generation of libraries of such tags in the future.
- Herner, Andras,Nikic, Ivana,Kallay, Mihaly,Lemke, Edward A.,Kele, Peter
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supporting information
p. 3297 - 3306
(2013/06/05)
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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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- 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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- A charge transfer type pH responsive fluorescent probe and its intracellular application
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A new charge transfer pH fluorescent probe BTP has been prepared by the ethylene bridging of benzothiazole and pyridine. The probe exhibits a specific fluorescent response to pH with a large Stokes shift, and the pH-induced emission enhancement factor (EEF) is about 22-fold when the pH is increased from 3.2 to 5.2. The presence of metal cations such as Na+, K +, Ca2+, Mg2+ and other transition metal cations does not interfere with its fluorescent pH response. In addition, the intracellular pH fluorescent imaging ability of the probe has been confirmed on macrophage cells using a confocal microscope. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Liu, Zhipeng,Zhang, Changli,He, Weijiang,Qian, Fang,Yang, Xiaoliang,Gao, Xiang,Guo, Zijian
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scheme or table
p. 656 - 660
(2010/06/18)
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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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- Synthesis, crystal structure and antiproliferative evaluation of some new substituted benzothiazoles and styrylbenzothiazoles
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The multistep synthesis of a series of new substituted-benzothiazoles as hydrochloride or quaternary salts is described. 6-Amidino substituted 2-aminobenzothiazoles (5, 6), N-methyl-2-(4-cyanostyryl)benzothiazolium iodide (8), cyano-substituted-2-styrylbenzothiazoles (9-11) and amidino and bis-amidino-substituted 2-styrylbenzothiazoles (12-17) were prepared. The crystal structure of amidino derivative (6) was determined by single crystal X-ray analysis. All new prepared compounds were tested on the cytostatic activities against malignant cell lines: (SW620, colon carcinoma; Hep2, laryngeal carcinoma; HBL, melanoma; HeLa, cervical carcinoma and WI38, human normal fibroblasts). The compounds exerted a different inhibitory effect, depended on concentration and type of the cells. The best inhibitory effect was achieved with compounds (12-15), with slight differences among them. All of them inhibited the growth of examined tumor cell lines and also normal fibroblasts. Other examined compounds exhibited a moderate inhibitory effect, depending on type of the cells. Majority of them inhibited the growth of HeLa cells and WI38.
- Caleta,Grdisa,Mrvos-Sermek,Cetina,Tralic-Kulenovic,Pavelic,Karminski-Zamola
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p. 297 - 305
(2007/10/03)
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