13373-28-9Relevant articles and documents
Ultrasensitive and selective fluorescent sensor for cysteine and application to drug analysis and bioimaging
Hu, Luping,Zheng, Tao,Song, Yanxi,Fan, Ji,Li, Hongqi,Zhang, Ruiqing,Sun, Yi
, (2021)
A fluorescent sensor based on coumarin-maleimide conjugate was developed for efficient discrimination of Cys from Hcy and GSH in both organic and aqueous solution. Addition of Cys to the non-fluorescent sensor solution in DMF induced bright blue fluorescence and enhanced the fluorescence intensity by 320-fold while other amino acids and biothiols (Gly, Hcy, GSH, Glu, Val, Tyr, Arg, Trp, Lys, His, Leu, Phe, Asp and Met) did not bring about remarked change. The sensor responds to Cys extremely rapidly. If Cys was added to the sensor solution, the fluorescence intensity increased by 170-fold immediately and attained the maximum value in 5 min. A linear relationship was observed between Cys concentration within 2–20 μM and the fluorescence intensity of the sensor solution. The detection limit of the sensor toward Cys is as low as 4.7 nM. The sensor is also effective for specific detection of Cys in aqueous (DMF/H2O = 9:1, v/v) solution. Practical application of the sensor to drug analysis and bioimaging of living Hela cells has been verified. Possible sensing mechanism of the sensor toward Cys has been proposed.
Synthesis and spectral study of novel benzopyrone and quinolinone derivatives
Mahmoud,El-Azm, F.S.M. Abu
, p. 535 - 541 (2013)
A series of novel benzopyrones and quinolinone derivatives were prepared using the readily obtainable 6-nitrobenzo- 2-pyron-3-carboxylate through the reaction with nitrogen nucleophilic reagents such as cyclohexyl amine, p-aminoacetophenone, diamines, hydrazine hydrate, thiosemicarbazide, anthranilic acid and carbon nucleophile as malononitrile. The IR, 1H NMR and mass spectra of the new synthesised compounds were discussed. Website
Effect of conformational flexibility on photophysics of bis-coumarins
Kielesiński, ?ukasz,Gryko, Daniel T.,Sobolewski, Andrzej L.,Morawski, Olaf W.
, p. 14491 - 14503 (2018)
The fluorescence intensity of bis-coumarins linked via CONH and COO functionalities are shown to exhibit a strong dependance on solvent polarity. The presence of the intramolecular hydrogen bond between the CO oxygen atom of coumarin and amide-NH moieties reduces the number of thermodynamically populated conformations in both ground and electronically excited states and an anti-arrangement of coumarin units is favored. Additionally, the rigidity of the linker raises the barrier to the conical intersection with the ground state, and in non-polar solvents strong fluorescence is observed. Although changing the CONH linking position from 3-7′ to 3-6′, does not remarkably affect the photophysics, replacement with a flexible ester linker allows the molecule a greater degree of conformational freedom due to the absence of the intramolecular hydrogen bonding interaction. The photophysical effect of this is the appearance of two fluorescence bands, the relative intensity and spectral positions of which are sensitive to the environment. Theoretical explorations of the excited-state potential energy surfaces performed with the aid of the ADC(2) ab initio electronic structure theory method revealed an exceptional wealth of concomitant photophysical processes. In particular, two channels for radiationless deactivation of the excited state were found; the first is related to the inter-ring twist of the coumarin units, and the second is associated with the excited-state intramolecular proton-transfer (ESIPT) from the CONH linker to the coumarin core.
Supramolecular synthesis of coumarin derivatives catalyzed by a coordination-assembled cage in aqueous solution
Li, Shao-Chuan,Cai, Li-Xuan,Zhou, Li-Peng,Guo, Fang,Sun, Qing-Fu
, p. 713 - 718 (2019)
A self-assembled Pd4L2 cage is employed as a water-soluble molecular flask for the synthesis of functionalized coumarins from a series of salicylaldehyde derivatives and cyanoacetates/malononitrile. The catalytic reaction features mild aqueous conditions and broad substrate scope. Crystal structures of the host-guest complexes for two substrates and one analogous intermediate have been obtained, shedding light on the supramolecular reaction mechanism. Michaelis-Menten kinetic studies were performed in one typical case, revealing that the rate of product formation has been enhanced by over 23-fold in contrast to the background reaction without cage. Moreover, the same reaction catalyzed by a smaller Pd6L4 cage gives a mixture of products and much lower yields, suggesting that fine-tuning on the size and symmetry of the cages’ cavity is crucial for their applications in supramolecular catalysis.
Preparative-scale synthesis of amino coumarins through new sequential nitration and reduction protocol
Chaudhari, Hemchandra K.,Pahelkar, Akshata,Takale, Balaram S.
, p. 4107 - 4110 (2017)
In contrast to the conventional deleterious approach for nitration (for example HNO3/H2SO4) and for reduction (for example Zn/HCl), we hypothesized that sensitive heterocycles such as coumarins could not withstand with those hard conditions. Hence, while studying this reaction sequence to prepare amino coumarins (which is our ongoing project to synthesize antitubercular coumarin agents), we came across mild and greener reagent for nitration using calcium nitrate (Ca(NO3)2·4H2O; lime nitrate), and reduction using D-glucose. These two mild, chemoselective, high yielding methods are discussed herein.
Solvent-Free FeCl3-Assisted Electrophilic Fluorine-Catalyzed Knoevenagel Condensation to Yield α,β-Unsaturated Dicarbonyl Compounds and Coumarins
Yang, Lu,Zhu, Jiang,Xie, Fukai,Peng, Xiaoshi,Lin, Bin,Liu, Yongxiang,Cheng, Maosheng
, p. 1053 - 1060 (2019/09/06)
A highly environmentally friendly procedure was developed for the Knoevenagel condensation of aromatic aldehydes with diethyl malonate in the presence of FeCl3 and N-fluorobenzenesulfonimide as a source of electrophilic fluorine under solvent-free conditions. The scope of the reaction was explored using commercially available substrates. The reaction with substituted salicylaldehydes afforded the corresponding coumarin derivatives which attract interest due to their potential medicinal importance.
