- Imidazopyridinium cations: A new family of azonia aromatic heterocycles with applications as DNA intercalators
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Two novel imidazopyridinium cations formed by a hexacyclic azonia aromatic system have been synthesized. Spectrofluorimetric titrations, circular dichroism measurements, theoretical simulations and fluorescence-based thermal denaturation experiments on these materials have shown the interesting fluorescence properties and DNA-binding ability by intercalation, with a marked preference for AT-rich sequences. Compound 2 presents the highest fluorescence quantum yield (0.32 in 5% DMSO/water and 0.46 in MeOH) and affinity for DNA (binding constant of ~4.5 × 105 M?1). Moreover, the potential of these compounds for cell staining has been investigated in living HeLa cells by confocal microscopy imaging. This analysis showed the remarkable capacity of both compounds for uptake and accumulation by living cells.
- Bosch, Pedro,García, Verónica,Bilen, Ba?ak S.,Sucunza, David,Domingo, Alberto,Mendicuti, Francisco,Vaquero, Juan J.
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- New unsymmetrical squaraine dyes derived from imidazo[1,5-A]pyridine
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The reaction of squaric acid with excess 3-methylimidazo[1,5-A]pyridine afforded almost exclusively the corresponding semisquaraine. The later underwent condensation with several heterocyclic compounds possessing active methyl groups, forming a novel class of unsymmetrical squaraines. The spectral properties of the obtained dyes were investigated and quantum-chemical calculations were performed to examine the dependence of the electronic structure and electron transitions on the molecular constitution of the dyes. The oxygen-generation ability of the new dyes was accessed by the 1,3-diphenylisobenzofuran (DPBF) quenching method, envisioning their potential use as sensitizers for photodynamic therapy (PDT).
- Prostota, Yaroslav,Kachkovsky, Oleksiy D.,Reis, Lucinda V.,Santos, Paulo F.
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- Thionyl chloride-mediated synthesis of 2-azaindolizine sulfur-bridged dimers by C-H bond direct chalcogenation of imidazo[1,5-a]pyridines
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Thionyl chloride-mediated chalcogenation of imidazo[1,5-a]pyridine serves as a new protocol for the synthesis of rare bisimidazopyridyl sulfides. This method provides the new route to synthesis of 2-azaindolizine sulfur-bridged dimers called chalcogenide
- Kulkarni, Mahesh R.,Lad, Nitin P.,Patil, Shashikant M.,Gaikwad, Nitin D.
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p. 1887 - 1894
(2020/05/04)
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- Synthesis of imidazo[1,5-a]pyridines via cyclocondensation of 2-(aminomethyl)pyridines with electrophilically activated nitroalkanes
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Imidazo[1,5-a]pyridines were efficiently prepared via the cyclization of 2-picolylamines with nitroalkanes electrophilically activated in the presence of phosphorous acid in polyphosphoric acid (PPA) medium.
- Aksenov, Alexander V.,Aksenov, Dmitrii A.,Arutiunov, Nikolai A.,Maliuga, Vladimir V.,Rubin, Michael
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p. 2903 - 2910
(2020/12/23)
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- Novel one-pot synthesis of dihydroacenaphtho[1,2-f][1,3]-oxazepines via 1,4-dipolar cycloaddition reaction
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A facile three-component reaction involving 3-alkyl(aryl)imidazo[1,5-a]pyridines 7a-g, dimethyl acetylenedicarboxylate 2 (DMAD) and acenaphthene-1,2-dione 5 led to the construction of the respective dihydroacenaphtho[1,2-f][1,3]oxazepine-10,11-dicarboxylates 10a-g in fair yields. Structures of the latter tetracyclic adducts, are based on NMR and MS spectral data and confirmed by single-crystal X-ray diffraction analysis for compound 10a. Most logically, the reaction proceeds via initial formation of the relevant diastereomeric spiro[1,3]oxazine-1,4-dipolar cycloadducts 12, 13 which then suffer skeletal rearrangement leading to the respective acenaphtho[1,2-f][1,3]oxazepines 10a-g.
- Sammor, Mervat S.,El-Abadelah, Mustafa M.,Hussein, Ahmed Q.,Awwadi, Firas F.
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p. 425 - 439
(2018/03/27)
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- Efficient Preparation of Imidazo[1,5- a ]pyridine-1-carboxylic Acids
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We report a novel and efficient approach to the synthesis of imidazo[1,5-a]pyridine-1-carboxylic acids. By using the reaction of 2-(aminomethyl)pyridine with acyl chlorides followed by one-pot treatment with trifluoroacetic anhydride, 2,2,2-trifluoro-1-im
- Tverdiy, Dmytro O.,Chekanov, Maksym O.,Savitskiy, Pavlo V.,Syniugin, Anatolii R.,Yarmoliuk, Sergiy M.,Fokin, Andrey A.
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p. 4269 - 4277
(2016/11/26)
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- Photochemical behaviour of a new 1,2,3,4-tetrahydroxanthylium fluorescent dye with "rhodamine-like" structure in liquid media and adsorbed onto a TiO2 photo-responsive substrate
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A new "rhodamine-like" fluorescent NIR dye based on the 9-(2′-carboxyphenyl)-6-(N,N-diethylamino)-1,2,3,4-tetrahydroxanthylium system was synthesized. Its spectral-luminescent properties were investigated both in solution and adsorbed onto a TiO2/su
- Concei??o,Ferreira,Prostota,Santos,Vieira Ferreira
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p. 279 - 288
(2016/02/27)
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- Cu(I)-catalyzed transannulation of N -heteroaryl aldehydes or ketones with alkylamines via C(sp3)-H amination
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A copper(I)-catalyzed direct transannulation of N-heteroaryl aldehydes or ketones with alkylamines via Csp3-H amination has been achieved using molecular oxygen as a sole oxidant. N-Heteroarenes are employed as the amine source. This transformation provides a rapid and concise access to multifunctional imidazo[1,5-a]pyridines.
- Li, Mingyang,Xie, Ying,Ye, Yong,Zou, Yong,Jiang, Huanfeng,Zeng, Wei
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supporting information
p. 6232 - 6235
(2015/02/19)
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- Approaches for the introduction of fluorinated substituents into [1,2,3]Triazolo[1,5-a]pyridines
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[1,2,3]Triazolo[1,5-a]pyridines functionalization with a trifluoromethyl group has been achieved for the first time using different synthetic strategies. Furthermore, these scaffolds have been employed as starting material in the synthesis of new 2,6-disubstituted pyridines containing the trifluoromethyl group, compounds that are not available using other methodologies. A fluorine-mediated triazolopyridine dimerisation is described, improving the previously known synthetic method. Preliminary studies focused on exploring triazolopyridines reactivity with electrophilic fluorine have revealed a new approach for the obtainment of imidazopyridines.
- Chiassai, Leonardo,Adam, Rosa,Drechslerová, Marcela,Ballesteros, Rafael,Abarca, Belén
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- New reactions of N-tert-butylimines; Formation of N-heterocycles by methyl radical elimination on flash vacuum thermolysis of N-benzylidene- and N-(2-pyridylmethylidene)-tert-butylamines
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Thermal reactions of N-benzylidene- and N-(2-pyridylmethylidene)-tert- butylamines (5 and 13) under FVT conditions have been investigated. Unexpectedly, at 800 °C, compound 5 yields 1,2-dimethylindole and 3-methylisoquinoline. In the reaction of 13 at 800 °C, 3-methylimidazo[1,5- a]pyridine was obtained as the major product. Mechanisms of these reactions have been proposed on the basis of DFT calculations. Furthermore, UV-photoelectron spectroscopy combined with FVT has been applied for direct monitoring and characterization of the thermolysis products in situ. Copyright
- Vu, Thien Y,Chrostowska, Anna,Huynh, Thi Kieu Xuan,Khayar, Said,Dargelos, Alain,Justyna, Katarzyna,Pasternak, Beata,Lesniak, Stanislaw,Wentrup, Curt
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supporting information
p. 14983 - 14988
(2013/11/06)
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- SYNTHESIS AND REARRANGEMENTS OF IMIDAZOLO- AND TRIAZOLO-DIAZINES
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3-Methylimidazolopyridine and 3-methyl-1,2,4-triazolopyrazine were prepared by coupling ethyl dithioacetate with 2-(aminomethyl)pyridine and 2-hydrazinopyrazine, respectively.Both compounds are stable in dilute acids and bases, unlike 3-methyl-1,2,4-triazolopyrimidine obtained by coupling the same dithioacetate with 2-hydrazinopyrimidine, which quickly undergoes a Dimroth type rearrangement.Coupling ethyl dithioacetate with 2-hydrazino-4-hydroxy-6-methylpyrimidine yielded a mixture of 3,5-dimethyl-1,2,4-triazolo-7(8H)-pyrimidone and 3,7-dimethyl-1,2,4-triazolo-5(8H)-pyrimidone, which were identified by 2D nmr.The last compound underwent a Dimroth rearrangement with acids to yield 2,5-dimethyl-1,2,4-triazolo-7(4H)-pyrimidone, whereas the first did not.Finally, coupling ethyl dithioacetate with 5-chloro-4-hydrazinopyrimidine afforded 8-chloro-3-methyl-1,2,4-triazolopyrimidine, which upon treatment with acids underwent a reversible ring opening to afford 2-chloro-1-formamido-2-(5-methyl-1,3,4-triazolo-2-yl)ethene.The latter on pyrolysis gave the starting base without undergoing rearrangement.
- Khadem, H. S. El,Kawai, J.,Swartz, D. L.
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p. 239 - 248
(2007/10/02)
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