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1.
Acta Crystallogr C Struct Chem ; 75(Pt 10): 1398-1404, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31589156

RESUMO

A study of three isomeric compounds containing a phenolic moiety attached to the nitrogen-rich triazolo-triazole bicycle is presented. In the three isomers, the phenolic OH group is in the ortho, meta and para positions. The crystal structure analysis of the meta isomer (C10H9N5O) shows that the 2H-tautomer is present in the crystal and that the molecule adopts a substantially planar geometry. However, the conformation found in the crystal is different compared to the monoprotonated cation of the same compound previously investigated in several salts. The packing of the meta isomer is driven by the formation of strong hydrogen bonds and shows the formation of infinite planar ribbons, parallel to a, formed around 21 crystallographic axes. The three isomers were tested against some cancer cell lines and also against normal cell lines. The ortho isomer shows a weak antiproliferative activity, the meta isomer shows significant antiproliferative activity against some cancer lines and no activity against healthy cell lines, and the para isomer is active against all the tested cell lines.

2.
Acta Crystallogr E Crystallogr Commun ; 74(Pt 2): 225-228, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29850059

RESUMO

Mol-ecules of the title compound, C24H8F4N2O8, have Ci point-group symmetry in the crystal, as they lie on crystallographic inversion centres (Z' = 1/2). The di-fluoro-phenyl ring is disordered over two orientations; the final refined occupancy factors of the two components of disorder are 0.947 (4) and 0.053 (4). In the crystal, some Car-H⋯F inter-actions are present, which involve the most acidic H atom of the mol-ecule.

3.
J Org Chem ; 82(10): 5155-5161, 2017 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-28452478

RESUMO

Fine control of the tautomeric forms of [1,2,4]triazolo[3,2-c][1,2,4]triazole derivatives in acidic conditions has been achieved by acting on the electronic character of the substituent at position 7 of the heterobicycle and on the counterion. Strong electron releasing or electron withdrawing substituents lead almost exclusively to a single tautomeric form, the 1H-3H or the 2H-3H, respectively. In the case of the phenol substituent, both tautomeric forms are present in comparable amount in solution; the two tautomers can also be selectively precipitated in different crystalline salts using suitable counterions.

4.
Front Chem ; 3: 22, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25870853

RESUMO

The association of 5',8-cyclo-2'-deoxyguanosine (cdG), a DNA tandem lesion, with its complementary base cytosine has been studied by voltammetry and NMR in chloroform, using properly silylated derivatives of the two nucleobases for increasing their solubilities. Both voltammetric data and NMR titrations indicated that the Watson-Crick complex of cytidine with cdG is weaker than that with guanosine, the difference being approximately of one order of magnitude between the two association constants.

5.
J Phys Chem B ; 119(17): 5462-6, 2015 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-25839102

RESUMO

Differential pulse voltammetries of guanine-rich single- and double-stranded oligonucleotides containing up to six consecutive guanines are reported. The observed progressive lowering of the first voltammetric peak potential as the number of adjacent guanines increases unambiguously points toward the establishment of delocalized hole domains; the hole stabilization energy is ca. 0.1 eV per GG step, significantly lower than that observed for AA steps.


Assuntos
DNA/química , Guanina , Oligonucleotídeos/química , Eletroquímica , Oxirredução , Termodinâmica
6.
J Phys Chem Lett ; 3(17): 2442-6, 2012 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-26292130

RESUMO

Time-resolved terahertz spectroscopy was employed for the investigation of charge-transport dynamics in benzothiadiazolo-dithiophene polyfluorene ([2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]) (APFO-3) polymers with various chain lengths and in its monomer form, all blended with an electron acceptor ([6,6]-phenyl-C61-butyric acid methyl ester, PCBM). Upon photoexcitation, charged polaron pairs are created, negative charges are transferred to fullerenes, while positive polarons remain on polymers/monomers. Vastly different hole mobility in polymer and monomer blends allows us to distinguish the hole and electron contributions to the carrier mobility.

7.
Acta Crystallogr C ; 64(Pt 8): o420-2, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18682646

RESUMO

The molecular structure of the title compound, C(12)H(15)NO(4), has several features related to steric hindrance due to the ester and dimethylamine groups being located ortho with respect to one another. In particular, the carbonyl group of the ester is not coplanar with the ring, the amine N atom is in a pyramidal arrangement [the N atom is 0.2161 (12) A from the three C atoms to which it is bonded] and the C atom of the adjacent ester group lies 0.3784 (14) A out of the plane of the aromatic ring. The deformations found in the X-ray structure have been confirmed by ab initio quantum mechanical calculations.

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