644-78-0Relevant articles and documents
Photo- and pH-induced transformations of flavylium cation: 'Write-lock- read-unlock-erase' cycles
Pina, Fernando,Melo, Maria Jo?o,Maestri, Mauro,Passaniti, Paolo,Camaioni, Nadia,Balzani, Vincenzo
, p. 3199 - 3207 (1999)
The structural transformations of flavylium ion in aqueous solutions caused by pH jumps and photoexcitation have been investigated. At pH +). By increasing pH, the concentration of AH+ decreases and, at pH = 5, this form is no longer present. The species obtained immediately after a pH jump undergo transformation processes with pH-dependent rate constants. At pH = 5.2 and 20 °C, the final product is the uncolored trans-chalcone (C(t)). This form can be transformed by light excitation into the cis-chalcone (C(c)) isomer, which is in equilibrium with the hemiacetal form (B(2)). This mixture is relatively inert due to the existence of a kinetic barrier that slows down the back thermal isomerization of C(c) to the stable C(t) form. Such a back reaction to C(t) can be totally prevented if the irradiated solution is submitted to a pH jump to pH = 1, which transforms the photoproducts into the stable AH+ species. In basic solution, two more species were detected, namely the anionic forms C(c)- and C(t)- of the cis and trans chalcone. C(t)- is a stable, not photosensitive and luminescent species, whereas C(c)- is not stable, being converted into C(t)- in the dark. The photochemical and pH- induced transformations of the flavylium cation in the pH range 0-11 can be taken as a basis to design write-lock-read-unlockerase cycles for an optical molecular-level memory with multiple readout capacity.
Formal cycloaddition of ethyl 2-aroyl-1-chlorocyclopropanecarboxylates:facile synthesis of diversified tetrahydrocyclopropa[b]chromenes
Xiong, Guoxi,Liao, Yong,Liu, Xue-Hui,Tang, Xiangying,Gong, Yuefa
, p. 1486 - 1491 (2018)
Tandem reaction of ortho-hydroxy chalcone with ethyl 2-aroyl-1-chlorocyclopropanecarboxylates has been disclosed, affording facile synthesis of diversified tetrahydrocyclopropa[b]chromenes via electron-deficient cyclopropene intermediate.
Synthesis, characterization and α-amylase and α-glucosidase inhibition studies of novel vanadyl chalcone complexes
Kaur, Mandeep,Kaushal, Raj
, (2020/10/06)
A series of chalcone ligands and their corresponding vanadyl complexes of composition [VO (LI–IV)2(H2O)2]SO4 (where LI = 1,3-Diphenylprop-2-en-1-one, LII = 3-(2-Hydroxy-phenyl)-1-phenyl-propenone, LIII = 3-(3-Nitro-phenyl)-1-phenyl-propenone, LIV = 3-(4-Methoxy-phenyl)-1-phenyl-propenone) have been synthesized and characterized using various spectroscopic (Fourier-transform infrared, electrospray ionization mass, nuclear magnetic resonance, electron paramagnetic resonance, thermogravimetric analysis, vibrating sample magnetometer) and physico-analytic techniques. Antidiabetic activities of synthesized complexes along with chalcones were evaluated by performing in vitro and in silico α-amylase and α-glucosidase inhibition studies. The obtained results displayed moderate to significant inhibition activity against both the enzymes by vanadyl chalcone complexes. The most potent complexes were further investigated for the enzyme kinetic studies and displayed the mixed inhibition for both the enzymes. Further, antioxidant activity of vanadyl chalcone complexes was evaluated for their efficiency to release oxidative stress using 2,2-diphenyl-1-picryl-hydrazyl-hydrate assay, and two complexes (Complexes 2 and 4) have demonstrated remarkable antioxidant activity. All the complexes were found to possess promising antidiabetic and antioxidant potential.
Synthesis of sulfonamides bearing 1,3,5-triarylpyrazoline and 4-thiazolidinone moieties as novel antimicrobial agents
Thach, Thi-Dan,Le, Thi Tuong-Vi,Nguyen, Huu Thien-An,Dang, Chi-Hien,Dang, Van-Su,Nguyen, Thanh-Danh
, p. 158 - 162 (2020/05/08)
Two series of sulfonamides were synthesized from 4-hydrazinylben-zenesulfonamide as the key starting material. 1,3,5-Triarylpyrazoline sulfonamides (2a-i) were obtained by cyclocondensation of various chalcones in 53-64 % yields, while 4-thiazolidinone derivatives (4a-e) were synthesized by cyclocondensation between mercaptoacetic acid and different phenylhydrazones in 43-62 % yields. The synthesized compounds were characterized based on FTIR, 1H-NMR, 13C-NMR and HRMS data. The sulfonamides were evaluated for their in vitro antimicrobial activities against four bacterial strains (E. coli, P. aeruginosa, B. subtillis and S aureus), two filamentous fungal strains (A. Niger and F. oxysporum) and two yeast strains (C. albicans and S. cerevisiae). Seven pyrazolines, 2a-c and 2e-h, exhibited significant inhibition of different microbial strains. Among them, compound 2b displayed good antifungal activity against A. Niger (MIC value at 12.5 μg mL-1) over the reference drug.
Highly enantioselective addition of aliphatic aldehydes to 2-hydroxychalcone enabled by cooperative organocatalysts
Chen, Le,Chen, Lu,Gao, Yu-Qi,Hou, Yi,Hu, Jiadong,Wen, Wen,Xie, Weiqing,Xu, Dongyang
supporting information, p. 10018 - 10021 (2020/09/15)
Herein, we developed an enantioselective addition of aliphatic aldehydes to 2-hydroxychalcone promoted by cooperative organocatalysts, giving access to hybrid flavonoids in excellent enantioselectivities. This reaction took advantage of cycloisomerization of 2-hydroxychalcone to form a transient flavylium under the irradiation of 24 W CFL, which was trapped by the in situ generated chiral enamine intermediate. The synergistic action of chiral phosphoric acid secured the excellent outcome of this reaction by ion-pairing with the transient flavylium.
