Search results for "Molecule"

Dual targeting of higher-order DNA structures by azacryptands induces DNA junction-mediated DNA damage in cancer cells

2021

Abstract DNA is intrinsically dynamic and folds transiently into alternative higher-order structures such as G-quadruplexes (G4s) and three-way DNA junctions (TWJs). G4s and TWJs can be stabilised by small molecules (ligands) that have high chemotherapeutic potential, either as standalone DNA damaging agents or combined in synthetic lethality strategies. While previous approaches have claimed to use ligands that specifically target either G4s or TWJs, we report here on a new approach in which ligands targeting both TWJs and G4s in vitro demonstrate cellular effects distinct from that of G4 ligands, and attributable to TWJ targeting. The DNA binding modes of these new, dual TWJ-/G4-ligands w…

Zur protonenkatalysierten Xanthenylierung von Tryptamin, Nω-Acetyltryptamin und Gramin: Ein Beitrag zur Konstitutionsaufklärung in der Indol-Analytik

1988

Zur protonenkatalysierten Aralkylierung von 1,2,3-Trimethylindol und 1,2,3,4-Tetrahydrocarbazol mit Arylaldehyden

1987

1,2,3-Trimethylindol (2) liefert mit Benzaldehyden die Kondensationsprodukte 5 und 6, wahrend aus den NH-Indolen 1 und 3 die Verbindungen 7 und 8 entstehen. Proton-catalyzed Aralkylation of 1,2,3-Trimethylindole and 1,2,3,4-Tetrahydrocarbazole with Arylaldehydes Reaction of 1,2,3-trimethylindole (2) with benzaldehydes leads to the condensation compounds 5 and 6, the NH-indoles 1 and 3, however, give 7 and 8.

ChemInform Abstract: High-Resolution Solid-State NMR Spectroscopy of Steroids and Their Derivatives

2013

Abstract: Steroids are an important class of organic compounds containing a vast array of biologically and physiologically essential molecules. Due to their availability, relatively straightforward derivatizability, and endogeneity, they are widely used in pharmacological applications. The investigation of molecular and physicochemical properties of active pharmaceutical ingredients (APIs) in the solid state is important, because these properties are directly related to their pharmacological activity. Several methods are available for this purpose. Solid-state NMR spectroscopy offers a nondestructive and flexible technique, providing both structural and dynamic information. It can be applie…

High-Resolution Solid-State NMR Spectroscopy of Steroids and Their Derivatives

2013

Abstract: Steroids are an important class of organic compounds containing a vast array of biologically and physiologically essential molecules. Due to their availability, relatively straightforward derivatizability, and endogeneity, they are widely used in pharmacological applications. The investigation of molecular and physicochemical properties of active pharmaceutical ingredients (APIs) in the solid state is important, because these properties are directly related to their pharmacological activity. Several methods are available for this purpose. Solid-state NMR spectroscopy offers a nondestructive and flexible technique, providing both structural and dynamic information. It can be applie…

Thermodynamic properties and conductivities of some dodecylsurfactants in water

1988

Densities, heat capacities, enthalpies of dilution, osmotic coefficients and conductivities are reported for dodecylamine hydrochloride, dodecyldimethylammonium and dodecyltrimethylammonium chloride in water over a wide range of concentration. The last two properties were also measured for dodecyltrimethylammonium bromide. From the thermodynamic data partial molar volumes, heat capacities and relative enthalpies and nonideal free energies and entropies were derived as a function of the surfactant concentration. The cmc's and degree of counterion dissociation were also calculated from the transport properties. It is shown that the trends of volumes, enthalpies, free energies and entropies ar…

Reaktionen von elektronenreichen Heterocyclen mit Orthocarbonsäure-Derivaten, 9. Acylierungsreaktionen von Indol und Methylindolen mit Dialkoxycarben…

1986

Indol und einige Methylderivate 1 lassen sich unter milden Bedingungen mit den Dialkoxycarbenium-tetrafluoroboraten 2 in meist guten Ausbeuten regioselektive acylieren. Mit dem Formylkation-Aquivalent 2a′ werden mit uberschussigem 1 auch die Bisindolycarbenium-tetrafluoroborate 13a – d erhalten. Reactions of Electron-rich Heterocycles with Orthocarboxylic Acid Derivatives, 9. – Acylation of Indole and Methylindoles with Dialkoxycarbenium Tetrafluoroborates Indole and some methylindoles 1 were acylated regioselectively with dialkoxycarbenium tetrafluoroborates 2 under mild conditions. The formyl cation equivalent 2a′ reacts with excess of indoles 1 to give the bisindolylcarbenium tetrafluoro…

Derivatisation of Pyrogallarenes

2005

Derivatisation of upper-rim hydroxy groups of pyrogallarenes produced completely acylated and tosylated pyrogallarene derivatives. Mesitylation of pyrogallarene, however, resulted in a regioselective derivatisation of hydroxy groups, i.e. eight OH groups out of 12 were mesitylated. Crystal structures of the synthesised pyrogallarene derivatives indicate that completely substituted pyrogallarenes exist in a distorted crown conformation despite of the lack of stabilising intramolecular hydrogen bonds. In contrast, the partially substituted pyrogallarene adopts a boat conformation and has an open cavity for the inclusion of small guest molecules. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinh…

A quantum mechanics/molecular mechanics study of the acylation reaction of TEM1 β-lactamase and penicillanate

2000

The acylation step in β-lactamase catalyzed hydrolysis of β-lactams has been explored by means of a quantum mechanics/molecular mechanics approach (AM1/CHARMM). The TEM1 enzyme, a class A β-lactamase, and the penicillanate constitute the system employed in our study. The entire molecular system is divided into a quantum and a classical region: the quantum part is composed by the substrate, the serine Ser70 and the essential moieties of key active site residues, Lys73, Ser130 and Glu166, as well as a water molecule present in the active site region, while the classical part is formed by the remaining residues and structural waters of the enzyme. In particular, the sequence of steps proposed …

Measuring single small molecule binding via rupture forces of a split aptamer.

2011

The rupture force of a split (bipartite) aptamer that forms binding pockets for adenosine monophosphate (AMP) was measured by atomic force spectroscopy. Changes in the rupture force were observed in the presence of AMP, while this effect was absent when mutant aptamers or inosine were used. Thus, changes in the rupture force were a direct consequence of specific binding of AMP to the split aptamer. The split aptamer concept allowed the detection of nonlabeled AMP and enabled us to determine the dissociation constant on a single-molecule level.