Search results for "Pyrimidine"

Unified model for the ultrafast decay of pyrimidine nucleobases.

2006

Ultrafast decay processes detected after absorption of UV radiation in gas-phase pyrimidine nucleobases uracil, thymine, and cytosine are ascribed to the barrierless character of the pathway along the low-lying 1(pipi*) hypersurface connecting the Franck-Condon region with an out-of-plane distorted ethene-like conical intersection with the ground state. Longer lifetime decays and low quantum yield emission are on the other hand related to the presence of a 1(pipi*) state planar minimum on the S1 surface and the barriers to access other conical intersections. A unified model for the three systems is established on the basis of accurate multiconfigurational CASPT2 calculations, whereas the ef…

Tautomerism of Diazepines Fused with Pyrimidine Rings.

2003

The tautomerism of 1,4-diazepines fused with pyrimidine rings was studied by means of nmr spec-troscopy, X-ray analysis and quantum chemical calculations. It was found that in the case of 6,8-diphenyl-pyrimido[4,5-b][1,4]diazepin-4-ols (7a - e) the enamine form is more stable than the diimine form. This result is rationalized with the electron-withdrawing effect of the 4-hydroxypyrimidine ring and with the formation of intermolecular hydrogen bonds. In contrast to 7a - e, the 6,8-diaryl-2,3,4,7-tetrahydro-1,3-dimethyl-1H-pyrimido[4,5-b][1,4]diazepine-2,4-diones (9a, c, f) exist in the diimine form.

The polypyrimidine tract-binding protein (PTB) is involved in the post-transcriptional regulation of human inducible nitric oxide synthase expression.

2006

Human inducible nitric oxide synthase (iNOS) expression is regulated by transcriptional and post-transcriptional mechanisms. We have recently shown that the multifunctional RNA-binding proteins KH-type splicing regulatory protein and tristetraprolin are critically involved in the post-transcriptional regulation of human iNOS expression. Several reports have shown that KH-type splicing regulatory protein colocalizes with the polypyrimidine tract-binding protein (PTB), and both RNA-binding proteins seem to interact with the same mRNAs. Therefore we analyzed the involvement of PTB in human iNOS expression. In human DLD-1 cells, cytokine incubation necessary to induce iNOS expression did not ch…

Design, synthesis, and biological evaluation of pyridothienotriazolopyrimidine derivatives as new HSP90 inhibitors

2010

The clinical relevance of low-density-lipoproteins size modulation by statins.

2006

The predominance of small, dense low density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III; in fact, LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease. Several studies have also shown that the therapeutical modulation of LDL size is of great benefit in reducing the risk of cardiovascular events. Hypolipidemic treatment is able to alter LDL subclass distribution and statins are currently the most widely used lipid-lowering agents. Statins are potent inhibitors of hydroxy-methyl-glutaryl-coenzyme A reductase, the rate-limiting en…

CCDC 941509: Experimental Crystal Structure Determination

2014

Related Article: S. Rubino, V. Di Stefano, A. Attanzio, L. Tesoriere, M.A. Girasolo, F. Nicolò, G. Bruno, S. Orecchio, G.C. Stocco|2014|Inorg.Chim.Acta|418|112|doi:10.1016/j.ica.2014.03.028

CCDC 837170: Experimental Crystal Structure Determination

2012

Related Article: J.Martinez-Lillo, D.Armentano, G.De Munno, J.Cano, F.Lloret, M.Julve, J.Faus|2011|Inorg.Chem.|50|12405|doi:10.1021/ic202088s

CCDC 763268: Experimental Crystal Structure Determination

2011

Related Article: D.Visinescu, L.M.Toma, J.Cano, O.Fabelo, C.Ruiz-Perez, A.Labrador, F.Lloret, M.Julve|2010|Dalton Trans.|39|5028|doi:10.1039/b926912f

CCDC 161124: Experimental Crystal Structure Determination

2002

Related Article: D.Armentano, G.De Munno, J.Faus, F.Lloret, M.Julve|2001|Inorg.Chem.|40|655|doi:10.1021/ic000258q

CCDC 228622: Experimental Crystal Structure Determination

2004

Related Article: E.Escriva, J.Garcia-Lozano, J.Martinez-Lillo, H.Nunez, J.Server-Carrio, L.Soto, R.Carrasco, J.Cano|2003|Inorg.Chem.|42|8328|doi:10.1021/ic034126j