872-73-1Relevant articles and documents
A simple pyrene-pyridinium-based fluorescent probe for colorimetric and ratiometric sensing of sulfite
Xu, Guanshu,Wu, Huan,Liu, Xingang,Feng, Ruokun,Liu, Zhanxiang
, p. 322 - 327 (2015)
The fluorescent probe is constructed by incorporating an α, β-unsaturated pyridinium to a pyrene fluorophore. The chemodosimeter has shown a selective and sensitive response to sulfite anion over other various anions and biological thiol through a Michael addition of the sulfite to the alkene of the probe. Meanwhile, it can be easily observed that the color of the probe for sulfite changes from yellow to colorless by the naked eye, and from yellow to blue under UV lamp immediately after the sulfite is added.
Carbazole-based fluorescent probes for G-quadruplex DNA targeting with superior selectivity and low cytotoxicity
Wang, Ming-Qi,Yu, Quan-Qi
, (2020)
G-quadruplex DNA plays a very important role in clinical diagnosis and fluorescence analysis has attracted extensive attention. A class of carbazole-based fluorescent probes for the detection of G-quadruplex DNA was established in this work. In this system, the installation of an oligo(ethylene glycol) chain on the scaffold will improve the water-solubility and biocompatibility. The presence of styrene-like different side groups could tune the selectivity toward G-quadruplex DNA binding. Results revealed that the substitution pattern and position gave a great influence on the ability for the discrimination of the G-quadruplex from other DNA structures. Especially, probe E1 bound to G-quadruplex DNA with superior selectivity, which exhibiting almost no fluorescence response in the presence of non-G-quadruplex DNA structures. Comprehensive analyses revealed that E1 could bind both ends of the G-quadruplex, resulting in a significant increase of fluorescence emission intensity. Cellular uptake assay suggested that E1 could pass through membrane and enter living cells with low cytotoxicity.
Loop-mediated fluorescent probes for selective discrimination of parallel and antiparallel G-Quadruplexes
Lee, Sungjin,Nagarajachari, Upendra,Pandith, Anup,Park, Chin-Ju,Sannathammegowda, Krishnaveni,Seo, Young Jun,Siddappa, Ravi Kumara Guralamatta
, (2021/02/26)
Herein we report simple pyridinium (1–3) and quinolinium (4) salts for the selective recognition of G-quadruplexes (G4s). Among them, the probe 1, interestingly, selectively discriminated parallel (c-KIT-1, c-KIT-2, c-MYC) G4s from anti-parallel/hybrid (22AG, HRAS-1, BOM-17, TBA) G4s at pH 7.2, through a switch on response in the far-red window. Significant changes in the absorption (broad 575 nm → sharp 505 nm) and emission of probe 1 at 620 nm, attributed to selective interaction with parallel G4s, resulted in complete disaggregation-induced monomer emission. Symmetrical push/pull molecular confinements across the styryl units in probe 1 enhanced the intramolecular charge transfer (ICT) by restricting the free rotation of C[dbnd]C units in the presence of sterically less hindered and highly accessible G4 surface/bottom tetrads in the parallel G4s, which is relatively lower extent in antiparallel/hybrid G4s. We confirm that the disaggregation of probe 1 was very effective in the presence of parallel G4–forming ODNs, due to the presence of highly available free surface area, resulting in additional π-stacking interactions. The selective sensing capabilities of probe 1 were analyzed using UV–Vis spectroscopy, fluorescence spectroscopy, molecular dynamics (MD)–based simulation studies, and 1H NMR spectroscopy. This study should afford insights for the future design of selective compounds targeting parallel G4s.
Palladium-Catalyzed Direct Arylation of Alkylpyridine via Activated N-Methylpyridinium Salts
Chen, Xue,Li, Wen-Jing,Li, Shun,Tang, Juan,Du, Xi,Zheng, Xue-Li,Yuan, Mao-Lin,Fu, Hai-Yan,Li, Rui-Xiang,Chen, Hua
, p. 622 - 632 (2019/12/30)
An efficient Pd-catalyzed arylation of alkylpyridine based on the pyridinium activation strategy has been developed for synthesis of mixed aryl alkylpyridines. It was found that (1) the N-methyl group in the pyridinium salts acted as a transient activator and could be automatically departed after the reaction, (2) CuBr was an indispensable additive for achieving the C6-selective arylation, (3) the α-branched alkyl chain on the alkylpyridine greatly increased the yield of the product. Deuterium labelling experiment revealed that in the case of the α-branched alkylpyridine, the presence of CuBr completely inhibited the H/D exchange at the benzylic position and thus enabled the selective arylation at the C6 position. This protocol demonstrates a broad substrate scope, and with respect to both the aryl iodides and the α-branched alkylpyridine, the desired mixed aryl alkylpyridines were obtained in generally good to excellent yields.
Stereodivergent Synthesis of Alkenylpyridines via Pd/Cu Catalyzed C-H Alkenylation of Pyridinium Salts with Alkynes
Chen, Hua,Haiyan, Fu,Jiang, Weidong,Li, Ruixiang,Li, Shun,Li, Wenjing,Tang, Juan,Xu, Bin,Yuan, Maolin,Zheng, Xueli
supporting information, p. 7814 - 7819 (2020/11/03)
The first Pd/Cu catalyzed selective C2-alkenylation of pyridines with internal alkynes has been developed via the pyridinium salt activation strategy. Importantly, the configuration of the product alkenylpyridines could be tuned by the choice of the proper N-alkyl group of the pyridinium salts, thus allowing for both the Z- and E-alkenylpyridines synthesized with good regio- and stereoselectivity. A plausible mechanism was proposed based on the Hammett study and KIE experiment.
Aggregation enhanced responsiveness of rationally designed probes to hydrogen sulfide for targeted cancer imaging
Wang, Rongchen,Gu, Xianfeng,Li, Qizhao,Gao, Jie,Shi, Ben,Xu, Ge,Zhu, Tianli,Tian, He,Zhao, Chunchang
supporting information, p. 15084 - 15090 (2020/10/13)
Activatable molecular probes hold great promise for targeted cancer imaging. However, the hydrophobic nature of most conventional probes makes them generate precipitated agglomerate in aqueous media, thereby annihilating their responsiveness to analytes a
Synthesis and antileishmanial evaluation of thiazole orange analogs
Abdelhameed, Ahmed,Liao, Xiaoping,McElroy, Craig A.,Joice, April C.,Rakotondraibe, Liva,Li, Junan,Slebodnick, Carla,Guo, Pu,Wilson, W. David,Werbovetz, Karl A.
supporting information, (2019/11/28)
Cyanine compounds have previously shown excellent in vitro and promising in vivo antileishmanial efficacy, but the potential toxicity of these agents is a concern. A series of 22 analogs of thiazole orange ((Z)-1-methyl-4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)quinolin-1-ium salt), a commercial cyanine dye with antileishmanial activity, were synthesized in an effort to increase the selectivity of such compounds while maintaining efficacy. Cyanines possessing substitutions on the quinolinium ring system displayed potency against Leishmania donovani axenic amastigotes that differed little from the parent compound (IC50 12–42 nM), while ring disjunction analogs were both less potent and less toxic. Changes in DNA melting temperature were modest when synthetic oligonucleotides were incubated with selected analogs (ΔTm ≤ 5 °C), with ring disjunction analogs showing the least effect on this parameter. Despite the high antileishmanial potency of the target compounds, their toxicity and relatively flat SAR suggests that further information regarding the target(s) of these molecules is needed to aid their development as antileishmanials.
Mixed halide hybrid halobismuthates and their in situ transformations
Kotov, Vitalii Yu.,Ilyukhin, Andrey B.,Buikin, Petr A.,Yorov, Khursand E.
, p. 537 - 540 (2019/10/28)
During a formation of four mixed hybrid halobismuthates (two of them have new structures) from solutions containing both Br? and I? ions, solid products enriched with iodine were isolated. Either oxidation or drying of mother liquors resulted in products with even higher iodine contents, up to pure iodobismuthates. All the compounds were characterized by a set of comprehensive methods (NMR, X-ray, DRS, etc.).
Iodide···π Interactions of Perhalogenated Quinoid Rings in Co-crystals with Organic Bases ?
Mol?anov, Kre?imir,Mali, Gregor,Grdadolnik, Jo?e,Stare, Jernej,Stilinovi?, Vladimir,Koji?-Prodi?, Biserka
, p. 5182 - 5193 (2018/08/06)
First anion···π contacts with quinoid rings have been described in novel co-crystals of tetrabromo- and tetrachloroquinone with iodide salts of substituted N-methylpyridinium cations. In seven crystal structures of these co-crystals, a centrosymmetric unit I-···quinone···I- is observed involving close contacts between iodide anions and electron-depleted carbon skeletons of the quinoid rings. However, the salt with N-methyl-4-methylcarboxypyridinium base crystallizes in two polymorphs characterized by O=C···quinone···C=O interaction instead of I-···quinone···I- one. A possible charge transfer, suggested by the black color of the crystals, is probed by solid-state NMR and IR spectroscopies and analyzed by DFT calculations.
Competing processes in the photochemistry of picolines and their N-methyl salts: photoinduced charge transfer, phototransposition and photohydration
Bla?ek Bregovi?, Vesna,Basari?, Nikola
, p. 859 - 871 (2017/02/10)
Photochemical reactivity of a series of picolines and their N-methylated salts has been investigated by preparative irradiations and UV–vis spectroscopy. Understanding competing photochemical processes and knowledge of their relative efficiencies is important in the application of pyridines as photocages or in the synthesis of complex polycycles. Contrary to previous reports for the gas phase, picolines are not reactive in the phototransposition, presumably due to protonation of the pyridine nitrogen in the excited state. Deuterium exchange was observed upon irradiation in CD3CN–D2O, but it was rationalized by photoionization and radical formation. On the other hand, N-methylated picoline salts are not protonated upon excitation. They undergo photohydration and phototransposition (ΦR?=?0.01–0.06). Upon irradiation of iodides, azabicyclic [3.1.0] hydration products were obtained. A difference in product distribution was observed between iodides and perchlorates, due to photoelimination of perchloric acid leading to the thermal aziridine ring opening. Moreover, excitation of iodide derivatives gives rise to change transfer transition forming iodide radicals that eventually give I3 ? with the quantum efficiency ΦR?=?0.015–0.02.
