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1.
Entropy (Basel) ; 23(2)2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33530405

RESUMO

In the framework of the multifractal hydrodynamic model, the correlations informational entropy-cross-entropy manages attractive and repulsive interactions through a multifractal specific potential. The classical dynamics associated with them imply Hubble-type effects, Galilei-type effects, and dependences of interaction constants with multifractal degrees at various scale resolutions, while the insertion of the relativistic amendments in the same dynamics imply multifractal transformations of a generalized Lorentz-type, multifractal metrics invariant to these transformations, and an estimation of the dimension of the multifractal Universe. In such a context, some correspondences with standard cosmologies are analyzed. Since the same types of interactions can also be obtained as harmonics mapping between the usual space and the hyperbolic plane, two measures with uniform and non-uniform temporal flows become functional, temporal measures analogous with Milne's temporal measures in a more general manner. This work furthers the analysis published recently by our group in "Towards Interactions through Information in a Multifractal Paradigm".

2.
Dalton Trans ; 45(33): 13126-34, 2016 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-27276499

RESUMO

In order to examine whether the length of the bridging chain in ansa-ferrocenes affects their antiproliferative activity against MDA-MB-231 triple negative breast cancer cell lines (TNBC), we synthesized derivatives of the type 1-[bis-(4-hydroxyphenyl)]methylidene-[n]ferrocenophane and 1-[(4-hydroxyphenyl)-phenyl]methylidene-[n]ferrocenophane with n = 3, 4, 5. We found that the derivatives of [3]ferrocenophane, the compounds with the shortest bridging chains, are the most active. IC50 values were 0.09 ± 0.01, 2.41 ± 0.10, and 1.85 ± 0.25 µM for the dihydroxyphenyl derivatives, with n = 3, 4, 5, respectively. These differences can be explained in terms of modification of the key metabolites (radical versus quinone methides) within the ansa series depending on the length of the bridging chain. The derivative of [5]ferrocenophane, possessing two -[bis-(4-hydroxyphenyl)]methylidene groups, was also prepared. Surprisingly, this relatively large molecule is also active (IC50 = 2.7 ± 0.3 µM). Two ruthenocenophane analogs were also synthesized. These ruthenium compounds are practically inactive against MDA-MB-231 cells. The unusual chemistry of these different compounds is discussed in terms of elucidating the mechanism underlying their diverse antiproliferative activity, and their specific advantages are evaluated.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Metalocenos/química , Metalocenos/farmacologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos
3.
Dalton Trans ; 43(44): 16557-79, 2014 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-25307172

RESUMO

Chiral ferrocene derivatives belong to privileged ligand classes for asymmetric transition metal catalysed reactions. Hetero-bidentate phosphane ligands are hybrid ligands, which combine the properties of phosphorus with those of other donor atoms. This feature creates further asymmetry around the metal centre, which may be helpful for increasing the stereoinduction. Therefore, hetero-bidentate ligands are useful alternatives to homo-bidentate ligands. Ligands featuring phosphorus and nitrogen or sulphur are quite common. From among ferrocene catalysts, ferrocenyl amino phosphanes and phosphane oxazolines serve as excellent examples. Fesulphos and ThioClickFerrophos are notable P,S-ligand examples. On the other hand, combinations of phosphorus with oxygen or carbon are only beginning to show their potential in asymmetric catalysis. Another useful feature in ligands of this type is the markedly different coordination properties of donor atoms, resulting in interesting opportunities for catalysis. Ferrocenyl MOP-analogues or a fascinating combination of phosphane and secondary phosphane-oxide would represent this ligand class. The last section of the review focuses on phosphanes combined with carbon-based donor atoms that are phosphane-alkene and phosphane-carbene ligands. This review focuses on the applications of these hetero-bidentate ferrocene ligands in asymmetric catalysis with a special emphasis on the most recent and influential literature reports.

4.
Chemistry ; 13(4): 1268-72, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17091517

RESUMO

Michael additions of malonodinitrile as well as several other reagents to chalcone have been found to proceed well in pure ionic liquids, without the addition of any catalyst. The catalytic effect of the residual acidity caused by hydrolysis of ionic liquids anions was excluded because HCl in dichloromethane did not catalyse the Michael addition of malonodinitrile. Piperidine was tested as the catalyst and was found to be a much better catalyst in ionic liquids than in dichloromethane. Therefore, the following question arose: what is the effect of ionic liquids on the dissociation constants of C--H acids?

5.
Org Biomol Chem ; 4(7): 1420-4, 2006 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-16557332

RESUMO

Seventeen organocatalyts were tested for their ability to catalyst the addition of thiophenols to chalcones in [bmim]PF6. The products were isolated in high yield after a short reaction time, but no stereoselectivity was observed. The reactions also proceeded (without any stereoselectivity) in four other ionic liquids. In contrast, 16% and 26% ee were observed when L-proline and cinchonine, respectively, were used as the catalysts in CH2Cl2. Addition of thiophenols is also catalysed by HCl, as well as D-mandelic and L-tartaric acids. Addition of thiophenols to chalcones also occurred in neat ionic liquids, without any additional catalyst, but the rate of the reaction depended considerably on the structure of ionic liquid. The scope of the non-catalysed reaction in ionic liquids was tested by the reactions of 5 different thiols and 3 different alpha-enones.


Assuntos
Cicloparafinas/química , Compostos Orgânicos/química , Compostos de Sulfidrila/química , Catálise , Cicloparafinas/síntese química , Hidrocarbonetos Clorados/química , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Solventes
6.
Molecules ; 11(2): 197-205, 2006 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-17962790

RESUMO

L-proline catalyzed additions of 13 different thiols to 11 different alpha-enone Michael acceptors in [bmim] PF(6 )are reported. Reasonable to high yields of the reaction products were isolated in most cases.


Assuntos
Cicloparafinas/química , Líquidos Iônicos , Compostos Orgânicos/química , Fenóis/química , Prolina/química , Compostos de Sulfidrila/química , Catálise , Cicloparafinas/síntese química , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , Solventes
7.
Molecules ; 10(6): 679-92, 2005 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-18007338

RESUMO

Five different silica gels containing two chiral ferrocenyl ligands were prepared by various synthetic routes and tested in an enantioselective Pd(0)-catalyzed allylic substitution and Rh-catalyzed hydrogenation. All the prepared anchored ligands were characterized by porosimetry data, DRIFTS spectra, thermal data and AAS. The aim of the work was to compare the influence of the carrier, surface properties and immobilization strategy on the performance of the catalyst.


Assuntos
Compostos Alílicos/química , Compostos Ferrosos/química , Catálise , Hidrogenação , Ligantes , Metalocenos , Paládio , Ródio , Dióxido de Silício
8.
Ultrason Sonochem ; 12(5): 401-3, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15590315

RESUMO

The sonochemical arylation of active methylene compounds with haloarenes have been studied. The reaction course was found to be dependent on the electron-withdrawing properties of substituent and the leaving group of haloarenes as well as of the character of active methylene compounds. The results of the sonochemical experiments were just slightly better than in the classical ones's, exception being reactions with phenylsulfonylacetonitrile.

9.
Ultrason Sonochem ; 12(1-2): 99-102, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15474960

RESUMO

Ultrasound effect on the Pd(0) catalysed reaction of arylboronic acid with halobenzenes was investigated. The effect of catalyst, base as well as solvent was tested. Heterogenous reaction of iodoarenes with different arylboronic acids, catalysed by Pd/C and KF as the base in methanol:water mixture resulted in good yields of cross-coupling products. Reaction time of sonochemical reaction was 1 h, while 4 h of reflux was necessary to achieve comparable results. Bromobenzenes gave best results using aqueous solution of PdCl2 as the catalyst, potassium carbonate as the base in toluene:water two phase system using TEBA (benzyltriethylammonium chloride) as PT catalyst. Chlorobenzenes gave just feeble yields of cross-coupling products.


Assuntos
Derivados de Benzeno/química , Ácidos Borônicos/química , Ácidos Borônicos/efeitos da radiação , Paládio/química , Sonicação , Água/química , Catálise , Reagentes de Ligações Cruzadas , Doses de Radiação
10.
Ultrason Sonochem ; 10(4-5): 265-70, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12818392

RESUMO

The sonochemical nucleophilic aromatic substitutions on haloarenes with different amines have been studied. A beneficial ultrasound effect was observed and high yields of the products were obtained after 15-30 min sonication. The reaction course of the nucleophilic aromatic substitution was found to be strongly dependent on nucleophilicity, bulkiness, and boiling point of amines as well as on the electron-withdrawing property of the substituents on the haloarenes.

11.
Spectrochim Acta A Mol Biomol Spectrosc ; 58(2): 363-71, 2002 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-11808740

RESUMO

UV-vis and fluorescence spectra of 2-[2-(4-cyclaminophenyl)ethen-1-yl] benzothiazoles 1 and their N-allylbenzothiazolium bromides 2 have been measured and interpreted. The substitution and solvent effects on electronic structure and spectra have been investigated. The benzothiazolium salts substituted with saturated cyclamines show strong push-pull character and can be used as potential NLO materials. Formation of aggregated structures was observed at higher concentrations of the benzothiazolium bromides.


Assuntos
Análise Espectral , Tiazóis/química , Benzotiazóis , Solventes/química
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