1032-98-0Relevant articles and documents
Synthesis and free radical scavenging activity of coumarin derivatives containing a 2-methylbenzothiazoline motif
Khoobi, Mehdi,Emami, Saeed,Dehghan, Gholamreza,Foroumadi, Alireza,Ramazani, Ali,Shafiee, Abbas
, p. 588 - 594 (2011)
Coumarin and benzothiazole scaffolds can be found in a number of natural or synthetic antioxidants. In an effort to develop a novel radical scavenger and potential antioxidant, a series of coumarin derivatives containing 2-methylbenzothiazoline motif and related compounds was synthesized and evaluated for their DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS ?+ (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radicals scavenging activities. Among them, 7-hydroxy-3-(2-methyl-2,3- dihydrobenzo[d]thiazol-2-yl)-2H-chromen-2-one (3e) has shown a significant free radical scavenging activity. From the structure-activity point of view, it was found that phenolic coumarin ring and benzothiazoline moiety in target compounds may contribute to the scavenging activity against free radicals. A series of coumarin derivatives containing a 2-methylbenzothiazoline motif and related compounds were synthesized and evaluated for their DPPH and ABTS ?+ radicals scavenging activities. 7-Hydroxy-coumarin derivative 3e showed a significant free radical scavenging activity. Copyright
Accessing the long-lived emissive 3IL triplet excited states of coumarin fluorophores by direct cyclometallation and its application for oxygen sensing and upconversion
Wu, Wenting,Wu, Wanhua,Ji, Shaomin,Guo, Huimin,Zhao, Jianzhang
, p. 5953 - 5963 (2011)
We studied four cyclometallated Pt(ii) complexes, in which the thiazo-coumarin ligands (Pt-2, Pt-3 and Pt-4) or the phenylthiazo ligand (Pt-1) were directly cycloplatinated. Pt-2 shows intense absorption in visible region but other complexes show blue-shifted absorption. Room temperature phosphorescence was observed for all the complexes, and the emission wavelength is dependent on the size of the π-conjugation, not the intramolecular charge transfer (ICT) feature of the CN ligands. Pt-2 shows longer phosphorescence lifetime (τ = 20.3 μs) than other complexes (below 2.0 μs). Furthermore, Pt-2 shows phosphorescence quantum yield Φ = 0.37, whereas Pt-3 and Pt-4 show much smaller Φ values (0.03 and 0.01, respectively). DFT/TDDFT calculations indicate 3IL triplet excited states for the complexes. The complexes were used as for luminescence O2 sensing and triplet-triplet-annihilation (TTA) based upconversion. Stern-Volmer quenching constant KSV = 0.026 Torr-1 was observed for Pt-2, ca. 89-fold of that of Pt-3. TTA upconversion is achieved with Pt-2 (λem = 400 nm with λex = 473 nm, anti-Stokes shift is 0.47 eV, excitation power density is at 70 mW cm-2). The upconversion quantum yield with Pt-2 as triplet sensitizer is up to 15.4%. The TTET efficiency (KSV = 1.33 × 105 M-1, kq = 6.57 × 109 M-1 s-1. DPA as quencher) of Pt-2 is 34-fold of the model complex [Ru(dmb) 3][PF6]2. Our results show that the 3IL state can be readily accessed by direct cyclometallation of organic fluorophores and this approach will be useful for preparation and applications of transition metal complexes that show intense absorption in visible region and the long-lived emissive 3IL excited states.
A one-pot reaction to synthesize two types of fluorescent materials containing benzothiazolyl moiety
Yu, Tianzhi,Zhang, Chengcheng,Zhao, Yuling,Chai, Haifang,Fan, Duowang,Ma, Ying,Yao, Shanglei,Li, Wentao
, p. 274 - 279 (2013)
Two different types of fluorescent materials containing benzothiazolyl moiety, 2-(benzothiazol-2-yl)phenol derivatives and 3-(benzothiazol-2-yl) coumarin derivatives, were synthesized synchronously using ethyl cyanoacetate, appropriate aromatic aldehyde and 2-aminothiophenol as the starting materials under the catalysis of benzoic acid by one-pot reaction. This method has the advantages of mild reaction conditions, easy processing and low waste. All synthesized compounds were characterized by elemental analysis, IR, 1H NMR spectra. The structures of 2-(benzothiazol-2-yl)phenol derivatives, 2-(benzothiazol-2-yl)phenol (BTP) and 2-(benzothiazol-2-yl)naphthol (BTN), were determined by X-ray single crystal analysis. The UV-vis absorption and photoluminescence spectra of all synthesized compounds were investigated. The 2-(benzothiazol-2-yl)phenol derivatives exhibit bright green emissions and 3-(benzothiazol-2-yl)coumarin derivatives emit bright blue light in solutions.
The one-pot synthesis and fluorimetric study of 3-(2′-benzothiazolyl)coumarins
Zhou, Shihai,Jia, Jianhong,Gao, JianRong,Han, Liang,Li, Yujin,Sheng, Weijian
, p. 123 - 128 (2010)
A novel, piperidene-catalysed, one-pot synthesis of 3-(2′-benzothiazolyl)coumarins was undertaken, starting from salicylaldehydes, ethyl cyanoacetate and o-aminobenzenethiols in ethanol. Salicylaldehydes with electron-donating group gave optimum yields. The novel method is characterized by mild reaction conditions, simple procedure and low waste. All compounds were fluorescent in solution emitting either green light (490?nm) or blue light (440-460?nm). Two typical fluorescence peaks were found in the three-dimensional fluorescence spectra.
Novel boronate probe based on 3-benzothiazol-2-yl-7-hydroxy-chromen-2-one for the detection of peroxynitrite and hypochlorite
Modrzejewska, Julia,Szala, Marcin,Grzelakowska, Aleksandra,Zak?os-Szyda, Ma?gorzata,Zielonka, Jacek,Podsiad?y, Rados?aw
, (2021/10/12)
Derivatives of coumarin, containing oxidant-sensitive boronate group, were recently developed for fluorescent detection of inflammatory oxidants. Here, we report the synthesis and the characterization of 3-(2-benzothiazolyl)-7-coumarin boronic acid pinacol ester (BC-BE) as a fluorescent probe for the detection of peroxynitrite (ONOO– ), with high stability and a fast response time. The BC-BE probe hydrolyzes in phosphate buffer to 3-(2-benzothiazolyl)-7-coumarin boronic acid (BC-BA) which is stable in the solution even after a prolonged incubation time (24 h). BC-BA is slowly oxidized by H2O2 to form the phenolic product, 3-benzothiazol-2-yl-7-hydroxy-chromen-2-one (BC-OH). On the other hand, the BC-BA probe reacts rapidly with ONOO?. The ability of the BC-BA probe to detect ONOO– was measured using both authentic ONOO– and the system co-generating steady-state fluxes of O2?– and?NO. BC-BA is oxidized by ONOO– to BC-OH. However, in this reaction 3-benzothiazol-2-yl-chromen-2-one (BC-H) is formed in the minor pathway, as a peroxynitrite-specific product. BC-OH is also formed in the reaction of BC-BA with HOCl, and subsequent reaction of BC-OH with HOCl leads to the formation of a chlorinated phenolic product, which could be used as a specific product for HOCl. We conclude that BC-BA shows potential as an improved fluorescent probe for the detection of peroxynitrite and hypochlorite in biological settings. Complementation of the fluorescence measurements by HPLC-based identification of oxidant-specific products will help to identify the oxidants detected.
