0000000000086154
AUTHOR
Elena Zaballos-garcía
showing 30 related works from this author
Gold nanoclusters for ratiometric sensing of pH in extremely acidic media.
2019
AuNCs capped with β-nicotinamide adenine dinucleotide phosphate exhibit an outstanding performance as fluorescent pH sensors; specifically they exhibit a high emission in strongly acidic media and linear dependence on pH in extremely acidic media (0.6–2.7) as well as in the 7.0–9.2 pH range, while they are unresponsive at intermediate pH values. Remarkably, these AuNCs make ratiometric sensing possible in extremely acidic media with a single fluorophore, specifically the nanocluster itself.
A tailor-made nucleoside-based colourimetric probe of formic acid
2014
A ratiometric, specific probe of formic acid has been developed. It is based on intermolecular nucleobase-pairing of inosine-capped plasmonic nanoparticles to form nucleoside channels, which are destabilised by the analyte.
Chemoselective reactions of N1-methyl-2-hydroxy-3-methylamino-3-phenylpropanamide with electrophiles. Synthesis of chiral hexahydro-4-pyrimidinones a…
2002
Abstract The reactivity of (2S,3S)-N1-methyl-2-hydroxy-3-methylamino-3-phenylpropanamide 1 , containing three nucleophilic centres has been studied against dihaloalkanes and aldehydes. Hexahydro-4-pyrimidinones or oxazolidines were obtained chemoselectively. Experimental results were explained by ‘ab initio’ calculations.
Experimental and theoretical DFT study of the reaction of 3-amino-1,2-diols with dichloromethane and paraformaldehyde
2004
Abstract The reactions of 3-phenyl-3-methylamino-1,2-propanediol 1a and 3-[(tert-butyldimethylsilyl)oxy]-1-methylamino-1-phenyl-2-propanol 1b with (CH2O)n and CH2Cl2 are appropriate procedures for the preparation of 1,3-oxazines or 1,3-oxazolidines under proper selection of kinetic or thermodynamic reaction conditions. The reaction of 1b with (CH2O)n or CH2Cl2, affords the oxazolidine 2b under kinetic conditions and then this compound can be slowly converted into 5-[(tert-butyldimethylsilyl)oxy]-3-methyl-4-phenyl-3,4,5,6-tetrahydro-2H-1,3-oxazine 3b under thermodynamic control. The mechanism proposed for this transformation and the effect of polar solvents on the acceleration of the reactio…
Quantitative ring contraction of 5-hydroxy-1,3-oxazin-2-ones into 5-hydroxymethyl-1,3-oxazolidin-2-ones: A DFT study
2007
Abstract The ring contraction of trans -5-hydroxy-1,3-oxazin-2-ones 1 into cis -5-hydroxymethyl-oxazolidinones 3 was studied with different bases and nucleophiles and it was found that it is the basicity and not the nucleophilicity the factor responsible for the ring contractions. A DFT study was made for the proposed mechanism.
ChemInform Abstract: Synthesis and Chemical Reactivity of 5-Methoxy-2-vinyl-4-azaindoles.
2010
Abstract 2-Vinyl-4-azaindoles are less reactive with dienophiles than 2-vinylindoles. 5-Methoxy-2-vinyl-4-azaindole 2a and its 1-methyl derivative 2a reacts with N-phenylmaleimide to yield cycloadducts only under vigorous conditions. 2b produces a cycloadduct with dimethyl acetylenedicarboxylate, while 2a yields a Michael-type adduct. Reactions with more reactive dienophiles gave only polymeric products.
CO2 switchable nanoparticles: reversible water/organic-phase exchange of gold nanoparticles by gas bubbling
2013
Gold nanoparticles capped with oleylamine can be effectively transferred from an organic solvent to water in the presence of an acetamidine surfactant by CO2 bubbling and then effectively reverted back to the organic phase by N2 bubbling.
Reaction of 3-Methylamino-1,2-diols with Dihalomethanes. Synthesis of Chiral 4-Substituted 3-Methyltetrahydro-1,3-oxazin-5-ols
2000
Abstract Enantiomerically pure 4,5-disubstituted 3-methyltetrahydro-1,3-oxazines have been obtained by reaction of 3-methylamino-1,2-diols with dichloromethane by regioselective differentiation of hydroxyl groups.
Reversible pH-induced fluorescence colour change of gold nanoclusters based on pH-regulated surface interactions.
2019
To prepare water-dispersible, biocompatible, ratiometric pH nanosensors is challenging. We report here for the first time that the emission colour of NAD+-capped AuNCs responds to the mono-/bidentate anchoring of the phosphoric groups of the ligand. The AuNCs exhibit a high luminescence (21% quantum yield) and an outstanding performance as fluorescent ratiometric pH sensors over a broad pH range.
Adenosine monophosphate-capped gold(i) nanoclusters: synthesis and lanthanide ion-induced enhancement of their luminescence
2016
Reduction of Au3+ in the presence of just adenosine 5′-monophosphate (AMP) and a zwitterionic organic chemical buffering agent, specifically 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), combined with light exposure, gives rise to luminescent, water-soluble Au+ nanoclusters (Au+ NCs). The photoluminescence of these NCs is considerably enhanced by adding Y3+ or the chemically similar Yb3+ lanthanide that leads to Au+/Y3+ and Au+/Yb3+ NCs, respectively. These NCs are characterised by absorption (steady-state), photoluminescence (steady-state and time-resolved), and X-ray photoelectron spectroscopy.
Synthesis, Characterisation, and Reactivity of 1-(1-Methylimidazol-2-yl)ethenes
1990
Abstract Thermally labile 1-(1-methylimidazol-2-yl)-ethenes, synthesised using the Wittig reaction, have been characterised as stable picrate or N-phenacyl salts. The free bases can be regenerated from the picrates on treatment with triethylamine and their reactivity with dienophiles is described.
Ring transformation of furfural into an unusual bicyclic system: Characterisation and dynamic stereochemistry of 6,7-diethoxycarbonyl-6,7-diaza-8-oxa…
1997
Abstract 2-Formylthiophene and 3-formylindole react with diethyl azodicarboxylate to give simple products derived from reactions on the formyl group whereas 2-formylfuran reacts to give the unexpected bicyclic title compound. 1 H and 13 C NMR studies indicate that this compound undergoes a series of three dynamic conformational changes over the temperature range 50 to −90°C which are ascribed to slow rotation about the exocyclic carbamate bonds and hindered bridge inversion.
Synthesis and characterization of new 1,4 and 1,5-disubstituted glucopyranosyl 1,2,3-triazole by 1,3-dipolar cycloaddition
2009
Abstract A series of 1,4 and 1,5-disubstituted 1-(β- d -glucopyranosyl)-1,2,3-triazoles has been prepared in an efficient manner with excellent yields using the intermolecular 1,3-dipolar cycloaddition of 1-azido-2,3,4,6-tetra-O-acetyl-β- d -glucopyranose 2 to a variety of substituted alkynes phenylacethylene 3, propargyl alcohol 4, 2-butyn-1,4-diol, 5, 3-propargylbenzimidazole 6 and propargylpyrazole 7 in toluene. The reaction takes place with the formation of both 4- and 5-regioisomers.
A Facile Synthesis of New 3-Substituted-2,3- dihydropyrido[3,2-d]pyrimidine-2,4-diones
2004
Abstract Pyrido[3,2-d]pyrimidine-2,4-diones derivatives have been synthesized in good yields by two efficient synthetic routes, the first one through an hetero-cyclization on the ureas derivatives 3a–e under alkaline conditions, the second one by condensation of the isocyanate 2 with various arylalkylamines in pyridine.
Synthesis, characterization and X-ray structure of heterocyclic systems prepared via 1,3-dipolar cycloaddition of nitrile oxides with benzimidazolone
2018
Abstract We report here a one-step synthesis of the new isoxazolyl-benzimidazolones and isoxazolinyl-benzimidazolones by 1,3-dipolar cycloaddition of the p-substituted benzonitrile oxides and mesitonitrile oxide with 1-cyclohex-1-en-1-yl-3-propargyl-benzimidazolone or 1-cyclohex-1-en-1-yl-3-allyl-benzimidazolone. In all cases these cycloadditions are completely regio- and chemoselective. The structures of new cycloadducts obtained are elucidated by their analytical and spectral data. The relative stereochemistry of the cycloadduct 8 was confirmed by single crystal X-ray analysis.
Synthesis and Chemical Reactivity of 5-Methoxy-2-vinyl-4-azaindoles
1997
Abstract 2-Vinyl-4-azaindoles are less reactive with dienophiles than 2-vinylindoles. 5-Methoxy-2-vinyl-4-azaindole 2a and its 1-methyl derivative 2a reacts with N-phenylmaleimide to yield cycloadducts only under vigorous conditions. 2b produces a cycloadduct with dimethyl acetylenedicarboxylate, while 2a yields a Michael-type adduct. Reactions with more reactive dienophiles gave only polymeric products.
Asymmetric synthesis of (−)-pseudoephedrine from (2S,3S)-3-phenyloxiran-2-ylmethanol. Stereospecific interchange of amino and alcohol functions
2001
Abstract A ring-opening reaction of N -methylaziridines with Boc 2 O/NaI has been applied to the asymmetric synthesis of pseudoephedrine. 3-Methylamino-3-phenyl-1,2-propanediol 1 , derived from (2 S ,3 S )-3-phenyloxiran-2-ylmethanol, was converted into the oxazolidin-2-one 4 , a precursor of pseudoephedrine. The reaction occurs with a stereospecific interchange of amino and alcohol functions.
Synthesis of 1,3-Oxazolidines and 1,3-Dioxolanes by Reaction of (2R, 3R)-3-Methylamino-3-phenyl-1,2-propanediol with Electrophiles
2003
Abstract The chemoselective reaction of (2R, 3R)-3-methylamino-3-phenyl-1,2-propanediol 1 with dimethoxypropane and dichloromethane under different conditions are reported as useful preparative procedures, for the synthesis 1,3-oxazolidines and 1,3-dioxolanes.
Experimental and theoretical investigations for the regio and stereoselective transformation of trans 1,2,3-trisubstituted aziridines into trans oxaz…
2003
The regio and stereoselective transformation of trans 1,2,3-trisubstituted aziridines into trans oxazolidin-2-ones takes place in good yield. However, the cis configuration at C2 and C3 in monocyclic aziridines is a limiting factor for this transformation. Ab initio calculations show that while the ring-opening process assisted by iodide is regioselective, the subsequent ring-closure is responsible for the retention of the configuration at the trans oxazolidin-2-ones. The larger energy found for the ring-closure process for the cis aziridines accounts for the non-formation of the cis oxazolidin-2-ones.
Synthesis of 1,3-Oxazolidines and 1,3-Dioxolanes by Reaction of (2R,3R)-3-Methylamino-3-phenyl-1,2-propanediol with Electrophiles.
2004
Abstract The chemoselective reaction of (2R, 3R)-3-methylamino-3-phenyl-1,2-propanediol 1 with dimethoxypropane and dichloromethane under different conditions are reported as useful preparative procedures, for the synthesis 1,3-oxazolidines and 1,3-dioxolanes.
Study of cyclic derivatives of 1,2-and 1,3-aminoalcohols as chiral catalysts in additions of diethylzinc to benzaldehyde
2005
The enantioselectivity of the addition reactions of diethylzinc to benzaldehyde in the presence of cyclic derivatives of 1,2- and 1,3-aminoalcohols as catalysts has been studied.
Synthesis of new polydentate oxalamide-based ligands as chiral catalysts for the enantioselective addition of diethylzinc to benzaldehyde
2006
New polydentate oxalamide-based ligands have been studied as chiral catalysts in the enantioselective addition of diethylzinc to benzaldehyde
Water-Soluble Naked Gold Nanoclusters Are Not Luminescent.
2017
We report here the synthesis of water-dispersible naked gold nanoclusters (AuNCnaked) by a simple reduction of HAuCl4 with NaOH at room temperature and show that they are non-luminescent. They were then easily passivated with different thiols and adenosine monophosphate to lead to luminescent NCs. This is an important finding as the photoluminescence of the passivated NCs can now be clearly attributed to the ligand-AuNC surface interaction. These results are also highly relevant from the point of view of the preparation of luminescent NCs from the same NC batch. This strategy can be valuable for the preparation of a broad range of nano(bio)composites.
Reactivity difference between diphosgene and phosgene in reaction with (2,3-anti)-3-amino-1,2-diols
2006
In reactions of (2,3-anti)-3-amino-1,2-diols with diphosgene and phosgene and their conversion into 1,3-oxazolidin-2-ones, some differences in the stereochemistry of the reactions have been found with these two reagents. The reactions with phosgene afforded the expected cis-oxazolidinones, and in the reaction with diphosgene under the same reaction conditions, the trans-oxazolidinones were also obtained.
Unzipping Nucleoside Channels by Means of Alcohol Disassembly
2013
Gold nanoparticles capped with simple adenosine derivatives can form colloidal aggregates in nonpolar solvents. Theoretical calculations indicate the formation of organic channels by the supramolecular assembly of the nanoparticles by means of hydrogen bonds between the adenine moieties. The aggregates were only negligibly sensitive to nPrOH, iPrOH, and tBuOH, whereas some showed a similar response to MeOH and EtOH, and others showed high selectivity toward MeOH. DNA nucleoside derivatives (1-(2-deoxy-β-D-ribofuranosyl)-5-methyluracil and 2′,3′-O-isopropylideneadenosine) as well as thymine and other aromatic compounds such as pyrene derivatives (pyrene, 1-chloropyrene, 1-hydroxypyrene, (1-p…
Efficient and simple synthesis of novel 1,2,3-triazolyl-linked benzimidazolone, molecular docking and evaluation of their antimicrobial activity
2020
In this study, a novel series of 1,2,3-triazolyl-benzimidazolone derivatives have been synthesized by click reaction of azides with benzimidazolones 2a–b. The latter compounds were prepared with excellent yields (85–97%), the structures of products were determined by spectral analysis. Then, the X-rays crystallographic analysis of compound 7a revealed the self-assembling properties. The new heterocycles were evaluated for their in vitro antimicrobial activities against Gram-positive and Gram-negative bacteria and against fungi strains. The most tested synthesized compounds showed potent antibacterial and antifungal activities against all tested strains. The compound 6c was found to be the m…
Thermolysis of 3-(carbazol-3-yl)-2-azidopropenoates
2000
Abstract Thermal cyclisation of 2-azido-3-(carbazol-3-yl)propenoic esters produces the 1,6-dihydropyrrolo[3,2- c ]carbazole and not the 1,9-dihydropyrrolo[2,3- b ]carbazole whereas, in the case of the 4-methylcarbazolyl derivative, the 1,9-dihydropyrrolo[2,3- b ]-carbazole is formed in preference to the alternative pyrido[4,3- c ]carbazole.
Pyrrole Studies. Part 40.1Synthesis of 2- and 3-Substitoted 1-Methylindoles from Vinylpyrroles.
1988
Abstract 4-Substituted-2-vinylpyrroles are more reactive than 2-substituted-4-vinylpyrroles in their reaction with DMAD to yield, respectively, 6/7- and 4,5-dihydroindoles, which are readily dehydrogenated to give indoles possessing electron-withdrawing substitutents at the 3- and 2-positions.
Novel examples of the N-methyl effect on cyclisations of N-Boc derivatives of amino alcohols. A theoretical study
2004
New examples of the N-methyl effect on the cyclisation of N-tert-butoxycarbonyl derivatives of amino alcohols are reported. Ab initio studies for the displacement step with formation of the five-membered heterocycle indicate that the increase of the nucleophile character of the carbonyl oxygen of the carbamate group with the N-methyl substitution is responsible for the acceleration of the cyclisation step.
CCDC 1820200: Experimental Crystal Structure Determination
2018
Related Article: Adardour Mohamed, Elena Zaballos-García, Loughzail Mohamed, Slimane Dahaoui, Abdesselam Baouid|2018|J.Mol.Struct.|1165|153|doi:10.1016/j.molstruc.2018.03.128