19012-03-4Relevant articles and documents
Light- and redox-gated molecular brakes consisting of a pentiptycene rotor and an indole pad
Kao, Chen-Yi,Lee, I-Tsun,Prabhakar, Ch.,Yang, Jye-Shane
, p. 507 - 516 (2014)
Two photochemically and electrochemically active alkenes 3Me and 3An containing pentiptycene and indole groups have been synthesized and investigated as light and/or redox-gated molecular brakes. The pentiptycene group functions as the four-bladed rotor, the indole group as the brake pad, and the vinylene group as the switch module. The E configuration corresponds to the brake-off state, in which the rotation of the rotor is free with a rotation rate of 108-109 at ambient temperature according to DFT calculations. The Z configuration corresponds to the brake-on state, in which the rotation rate is decreased to 101-102, depending on the N-substituent of indole, according to line-shape analysis of variable temperature 13C NMR spectra. The overall braking effect reaches a factor of 106-108. While the combined photochemical E → Z and electrochemical Z → E switching has a higher capacity than the two-way photochemical switching in the case of 3Me, the switching capacity are comparable for the two methods in 3An. The results also show that photochemical E-Z isomerization is much more reliable than the electrochemical counterpart, as the stability of the redox intermediates plays a critical role in determining the robustness of the molecular brakes via electrochemical switching. The photochemical and/or electrochemical switching between the E and Z isomers of two alkenes substituted with both pentiptycene and indole groups results in a change of the rotation rate as large as 106-108 fold for the pentiptycene group about the pentiptycene-vinylene C-C bond, corresponding to a new generation of light- and redox-gated molecular brakes.
Synthesis and evaluation of cyanine-styryl dyes with enhanced photostability for fluorescent DNA staining
Bohlaender, Peggy R.,Wagenknecht, Hans-Achim
, p. 7458 - 7462 (2013)
The photostability of cyanine-styryl dyes of the indole-quinolinium type can be significantly improved by structural variations while the excellent optical properties including the bright fluorescence in the presence of DNA can be maintained or even improved, too.
Synthesis of a photostable energy-transfer pair for dNA traffic lights
Bohl?nder, Peggy R.,Wagenknecht, Hans-Achim
, p. 7547 - 7551 (2014)
A new cyano-substituted thiazole red derivative as a red emitter and a novel green fluorescent donor dye of the cyanine styryl type were synthesized in good yields. Characterization of their optical properties revealed excellent photostabilities and large apparent Stokes' shifts. Both dyes can be incorporated into oligonucleotides through postsynthetic click -type chemistry and combined in a diagonal arrangement in double-stranded DNA. As a result, both dyes combine to an energy-transfer pair in DNA that shows remarkable optical properties such as significant emission wavelength shift from green to red upon hybridization owing to high energy-transfer efficiency between the two dyes and remarkable emission red/green color contrast ratio. The combination of these dyes as an energy-transfer pair according to our concept of DNA traffic lights has high potential for applications in molecular imaging.
Coumarin-indole conjugate donor-acceptor system: Synthesis, photophysical properties, anion sensing ability, theoretical and biological activity studies of two coumarin-indole based push-pull dyes
Aksungur, Tu??e,Ayd?ner, Burcu,Sefero?lu, Nurgül,?zkütük, Müjgan,Arslan, Leyla,Reis, Yasemin,A??k, Leyla,Sefero?lu, Zeynel
, p. 364 - 379 (2017)
Two coumarin-indole conjugate fluorescent dyes having donor-acceptor-donor (D-A-D) (CI-1 and CI-2) were synthesized, and characterized using IR, 1H/13C NMR and HRMS. The absorption and emission properties of the dyes were determined in different solvents. The anion sensitivity and selectivity of the dyes were studied with some anions (CN?, F?, AcO?, Cl?, Br?, I?, HSO4? and H2PO4?) in DMSO, and their interaction mechanisms were evaluated by spectrophotometric and 1H NMR titration techniques. In addition, the molecular and electronic structures of CI-1, as well as the molecular complexes of CI-1, formed with the anions (F? and AcO?), were obtained theoretically and confirmed by DFT and TD-DFT calculations. CI-1 behaves as a colorimetric chemosensor for selective and sensitive detection of CN? in DMSO/H2O (9:1) over other competing anions such as F? and AcO?. However, only CN? interacts with chromophore CI-2 via Michael addition and the main absorption maxima shifts hypsochromically with an observed distinctive color change from orange to yellow. For using as a optic dye, the thermal stability properties of the dyes was determined by TGA (Thermal Gravimetric Analysis). Antimicrobial, antifungal and DNA-ligand interaction studies of the dyes were also examined. The dyes cause conformational changes on DNA and selectively bind to nucleotides of A/A and G/G.
A simple and facile synthesis of novel 1,2,3-triazole substituted pyrimidine derivatives
Bakkolla, Mahesh Goud,Taduri, Ashok Kumar,Bhoomireddy, Rama Devi
, p. 2489 - 2497 (2020)
A series of novel indole and pyrimidine scaffolds bearing 1,2,3-triazoles have been designed and synthesized using click chemistry reaction conditions. Target compounds 9a-j were synthesized in the multi-step process. In the first step 5-substituted-1-methyl-1H-indole-3-carbaldehyde 2a-b reacted with ethyl cyanoacetate 3 and guanidine hydrochloride 4 in presence of L-Proline in ethanol undergoes cyclisation to form 5a-b. Further, 5a-b condensed with various benzaldehydes to form Schiff's base 6a-f, which further proporgylated with propargyl bromide to form 7a-f. Finally, 7a-f was subjected to click-chemistry with various azides in the presence of CuSO4.5H2O + sodium ascorbate mixture in Dimethylformamide at room temperature to obtain 2 + 3 cycloaddition products 9a-j in high yield. All these synthetic methods are mostly green and inexpensive with excellent yields.
Synthesis of Analogues of Indole Alkaloids from Sea Sponges – Aplysinopsins by the Reaction of Amines with (4Z)-4-[(1H-indol-3-yl)-methylene]-1,3-oxazol-5(4H)-ones
Suzdalev, Konstantin F.,Babakova, Maria N.
, p. 1200 - 1206 (2016)
A new two-step approach toward the synthesis of aplysinopsin analogues 5-(1-R-1H-indol-3-ylmethylene)-2-aryl-3,5-dihydroimidazol-4-ones consisting in obtaining and reaction of 4-(1-R-1H-indol-3-ylmethilene)-2-Ar-4H-oxazol-5-ones with amines was developed. The configuration of starting compounds and final products was determined by13С and1H-nmr spectroscopy.
Biomolecular recognition at the cellular level: Geometrical and chemical functionality dependence of a low phototoxic cationic probe for DNA imaging
Gaur, Pankaj,Kumar, Ajay,Bhattacharyya, Shalmoli,Ghosh, Subrata
, p. 4895 - 4900 (2016)
A combined approach was adopted to understand the impact of structural geometry as well as suitable chemical functionality of a molecular probe on its efficient binding in the minor groove of DNA. The development of a small chemical library of different lutidinium conjugates (P1-P5) and molecular simulations using DFT calculations clearly demonstrated that the semilunar conformation of a molecular probe equipped with requisite chemical functionality is the key parameter for its proper binding in the minor groove of DNA. The comparative optical responses of these probes (P1-P5) coupled with the theoretical studies illustrated that only P3 displayed considerable fluorescence enhancement in the presence of DNA because of its semilunar geometry and special chemical architecture. Furthermore, the bioassays clearly revealed that the probe can penetrate the cell membrane of live as well as dead cells without the help of any permeabilization agent. Microscopic cellular imaging established that probe P3 can stain the nuclear region of the cells with high contrast and negligible cytoplasmic spillage without causing any cellular deterioration. The specificity and binding efficiency of P3 toward DNA were established by performing DNase/RNase digest tests and gel electrophoresis experiments. Most importantly, P3 exhibited minimum phototoxicity and high photobleaching resistance in cellular medium under continuous exposure to a light source, which are highly desirable for real time monitoring of many biological events. Altogether, the investigated properties of P3 shed light on its admirable and persuasive standing as a cell-compatible, bright and photostable molecular probe for nuclear imaging in various bio-medical applications.
Amphiphilic Cyanine-Platinum Conjugates as Fluorescent Nanodrugs
Sun, Tingting,Li, Zhensheng,Xie, Zhigang,Jing, Xiabin
, p. 221 - 225 (2016)
Two fluorescent nanomedicines based on small molecular cyanine-platinum conjugates have been prepared via a nanoprecipitation method and characterized by transmission electron microscopy (TEM) as well as dynamic light scattering (DLS). The conjugates exhibited an enhanced fluorescence in their nanoparticle formulation compared to that in solution. The nanomedicines could be endocytosed by cancer cells as revealed by confocal laser scanning microscopy (CLSM) and showed high cellular proliferation inhibition. Fluorescent platinum nanomedicines prepared directly from small molecules could be an alternative strategy for developing new drugs with simultaneous cellular imaging and cancer therapy functions.
Anion–π Interactions in Light-Induced Reactions: Role in the Amidation of (Hetero)aromatic Systems with Activated N-Aryloxyamides
Buglioni, Laura,Mastandrea, Marco M.,Frontera, Antonio,Pericàs, Miquel A.
, p. 11785 - 11790 (2019)
The importance of anion–π interactions as a driving force for chemical and biological processes is increasingly being recognized. In this communication, we describe for the first time its key participation in light-induced reactions. We show, in particular, how transient complexes formed through noncovalent anion–π interactions between electron-poor N-aryloxyamides and multiply-charged anions (such as carbonate or phosphate) can undergo facile light-promoted N?O cleavage, affording amidyl radicals that can subsequently be trapped by (hetero)aromatics.
Yb(OTf)3catalyzed [1,3]-rearrangement of 3-alkenyl oxindoles
He, Lingchen,Hu, Xin-Gen,Jiang, Jun,Li, Juan,Li, Xinhua,Liu, Hongxin,Song, Chao,Wan, Junlin,Wu, Chaofei,Xiao, Hong-Ping
supporting information, p. 122 - 126 (2021/12/29)
A Yb(OTf)3catalyzed [1,3]-rearrangement of 3-alkenyl oxindoles was achieved, affording a variety of multifunctional 3-ylideneoxindoles with good yields andZ/Eselectivities (64%-89% yield, 78?:?22->99?:?1Z/E). Importantly, an operationally simple, one-pot sequential catalytic synthesis of 3-ylideneoxindoles was also developed. Additionally, a cross [1,3]-rearrangement experiment and nonracemic transformation were also carried out, which indicated a concerted rearrangement mechanism of this methodology.
