Search results for "ULTRAVIOLET"

SYNTHESIS AND PHOTOCHEMIOTHERAPEUTIC ACTIVITY OF THIOPYRANO[2,3-E]INDOL-2-ONES

2004

A series of derivatives of the new ring system thiopyrano[2,3-e]indol-2-one was prepared with the aim of obtaining new photochemotherapeutic drugs. Biological screenings were performed on this new class of photoactivable drugs and a strong antiproliferative effect was observed upon irradiation with UVA light. The compound bearing a methyl substituent at the pyrrole nitrogen resulted as the most interesting showing IC50 in the nanomolar range.

THIOPYRANO[2,3-E]INDOL-2-ONES: ANGELICIN HETEROANALOGUES WITH POTENT PHOTOANTIPROLIFERATIVE ACTIVITY

2008

A new class of compounds, the thiopyrano[2,3-e]indol-2-ones, bioisosters of the angular furocoumarin angelicin, was synthesized with the aim of obtaining new photochemotherapeutic agents. In particular 7,8-dimethyl-thiopyranoindolone 6c s showed a remarkable phototoxicity and a great dose UVA dependence reaching IC(50) values at submicromolar level. This latter photoinduced a massive apoptosis and a remarkable photodamage to lipids and proteins. Although it did not intercalate DNA, it was able to cause photooxidation of DNA bases.

Transient Midinfrared Study of Light Induced Dissociation Reaction of Ru(dcbpy)(CO)2I2 in Solution

2004

Illumination of Ru(dcbpy)I2(CO)2 (dcbpy = 4,4‘-dicarboxy-2,2‘-bipyridine) with (near) ultraviolet light induces dissociation of one of the CO groups of the complex. In solution the opened coordination site of the metal is occupied by a solvent molecule. In the present study the kinetics of the ligand exchange reaction has been studied in solution with femtosecond time resolution by probing the CO stretching vibrations of the reactant and the product molecules Ru(dcbpy)I2(CO)(EtOH) in the infrared and probing electronic transitions in the visible spectral regions. The kinetic results indicate that photoelimination of the CO group occurs on a subpicosecond time scale. The overall quantum yiel…

The interaction of deoxyribonucleic acid with methyltin(IV) moieties in solution studied by small-angle X-ray scattering, circular dichroism and UV s…

2000

The nature of calf thymus DNA in aqueous solution, in the presence of the organotin(IV) species Sn IV Me 3 , Sn IV Me 2 and Sn IV Me, possibly partly hydrolysed and/or hydrated, was investigated by small-angle X-ray scattering (SAXS), ultraviolet spectroscopy (UV) at different temperatures and circular dichroism (CD). The results are compared with those of previous 119 Sn Mossbauer studies on condensed DNA phases. The effects of tin-phosphate oxygen bonding on the DNA melting profile in DNA-Sn IV Me systems are in agreement with previous reports on DNA-Main Group metal ion interactions. The structure and conformation of the DNA double helix are not influenced by Sn IV Me n species, even in …

Untersuchungen zur Konformation und elektronischen Struktur von Cyclooctadieninen

1985

Die mit semiempirischer Quantenmechanik vorhergesagten Konformationen und elektronischen Strukturen der Cyclooctadienine 1 und 2 werden experimentell an Hand von 1H-NMR- und PE-Spektren verifiziert. Dabei wird Bezug genommen auf eine Reihe von anderen, verwandten Cycloalkinen 3–5 und Cycloalkenen 6–11. Wahrend die hohe geometrische Ringspannung entscheidenden Einflus auf 1 und 2 hat, ist eine Homoaromatizitat, die auf sechs nahezu eben angeordneten π-Elektronen-Zentren beruht, nicht signifikant. Investigations on the Conformation and the Electronic Structure of Cyclooctadienynes Conformations and electronic structures of the cyclooctadienynes 1 and 2, predicted by semi-empirical quantum mec…

Photochemie des 1,3‐Distyrylbenzols — Ein neuer Weg zu syn ‐[2.2](1,3)Cyclophanen

1986

Photochemie elektronenreicher 1,3‐Distyrylbenzole

1988

Die 1,3-Distyrylbenzole 3 mit bis zu sieben Alkoxygruppen werden der oxidativen Photocyclisierung unterworfen. Bei der Bildung der Produkte 6, 7 und 8 konnen als Konkurrenz- bzw. Folgeprozesse die Abspaltung von Methanol (3bb 7bb, 3bf 7bf) und die Chinonoxidation (3cf 8) auftreten. Die eigensensiblisierte Erzeugung von Singulettsauerstoff kann bei 6bf zur Endoperoxidbildung fuhren (6bf 11). Photochemistry of Electron-Rich 1,3-Distyrylbenzenes The 1,3-distyrylbenzenes 3, containing up to seven alkoxy groups, are subjected to the oxidative photocyclization. Elimination of methanol (3bb 7bb, 3bf 7bf) and quinone oxidation can occur as competitive or consecutive reactons in the formation of the…

Acid Titrations of poly(dG-dC).poly(dG-dC) in Aqueous Solution and in a w/o Microemulsion

2005

The model polynucleotide poly(dG-dC).poly(dG-dC) (polyGC) was titrated with a strong acid (HCl) in aqueous unbuffered solutions and in the quaternary w/o microemulsion CTAB/n-pentanol/n-hexane/water. The titrations, performed at several concentrations of NaCl in the range 0.005 to 0.600 M, were followed by recording the modifications of the electronic absorption and of the CD spectra (210or = lambdaor =350 nm) upon addition of the acid. In solution, the polynucleotide undergoes two acid-induced transitions, neither of which corresponds to denaturation of the duplex to single coil. The first transition leads to the Hoogsteen type synG.C+ duplex, while the second leads to the C+.C duplex. The…

Hemin-coupled iron(III)-hydroxide nanoparticles show increased uptake in Caco-2 cells

2011

Abstract Objectives The absorption of commonly used ferrous iron salts from intestinal segments at neutral to slightly alkaline pH is low, mainly because soluble ferrous iron is easily oxidized to poorly soluble ferric iron and ferrous iron but not ferric iron is carried by the divalent metal transporter DMT-1. Moreover, ferrous iron frequently causes gastrointestinal side effects. In iron(III)-hydroxide nanoparticles hundreds of ferric iron atoms are safely packed in nanoscaled cores surrounded by a solubilising carbohydrate shell, yet bioavailability from such particles is insufficient when compared with ferrous salts. To increase their intestinal uptake iron(III)-hydroxide nanoparticles …

Solar blind AlGaN photodetectors with a very high spectral selectivity

2006

Solar blind detectors based on AlGaN heterostructures grown on sapphire by Molecular Beam Epitaxy and with a dielectric interference filter deposited on the back side are demonstrated to provide record spectral selectivity. Rejection ratios of 2 x 10(4), and better than 5 x 10(4), measured between 280 and 320 nm, are achieved in Metal Semiconductor Metal detectors and Schottky diodes respectively. The whole detector process is fully compatible with low cost array fabrication.