Search results for "indole"
showing 10 items of 570 documents
Biomarkers to disclose recent intake of alcohol: potential of 5-hydroxytryptophol glucuronide testing using new direct UPLC-tandem MS and ELISA metho…
2007
Aims: This study compared two new methods for direct determination of 5-hydroxytryptophol glucuronide (GTOL) in urine, a biomarker for detection of recent alcohol consumption. Methods: Urine samples were collected from ten alcoholic patients during recovery from intoxication. A direct injection ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for measurement of the urinary GTOL to 5-hydroxyindoleacetic acid (5-HIAA) ratio, and an ELISA assay for direct measurement of GTOL, were used. Comparison was made with the urinary ethanol and ethyl glucuronide (EtG) concentrations. Results: The breath ethanol concentration on admission ranged between 1.0-3.1 g/l. Th…
Chemoenzymatic Synthesis of Functional Sialyl LewisX Mimetics with a Heteroaromatic Core
2014
Functional mimetics of the sialyl Lewis(X) tetrasaccharide were prepared by the enzymatic sialylation of a 1,3-diglycosylated indole and a glycosyl azide, which was subsequently transformed into a 1,4-diglycosylated 1,2,3-triazole, by using the trans-sialidase of Trypanosoma cruzi. These compounds inhibited the binding of E-, L-, and P-selectin-coated nanoparticles to polyacrylamide-bound sialyl-Lewis(X) -containing neighboring sulfated tyrosine residues (sTyr/sLe(X) -PAA) at low or sub-millimolar concentrations. Except for E-selectin, the mimetics showed higher activities than the natural tetrasaccharide.
3D Morphology, ultrastructure and development of Ceratomyxa puntazzi stages: first insights into the mechanisms of motility and budding in the Myxozo…
2012
Free, amoeboid movement of organisms within media as well as substrate-dependent cellular crawling processes of cells and organisms require an actin cytoskeleton. This system is also involved in the cytokinetic processes of all eukaryotic cells. Myxozoan parasites are known for the disease they cause in economical important fishes. Usually, their pathology is related to rapid proliferation in the host. However, the sequences of their development are still poorly understood, especially with regard to pre-sporogonic proliferation mechanisms. The present work employs light microscopy (LM), electron microscopy (SEM, TEM) and confocal laser scanning microscopy (CLSM) in combination with specific…
Crystallization and preliminary X-ray analysis of native and selenomethionyl vinorine synthase from Rauvolfia serpentina.
2005
Vinorine synthase (VS) is a central enzyme of the biosynthesis of the antiarrhythmic drug ajmaline and is a member of the BAHD superfamily of acyltransferases. So far, no three-dimensional structure with significant sequence homology with VS is known. Crystals of VS and selenomethionyl-labelled VS from the medicinal plant Rauvolfia serpentina have been obtained by the hanging-drop technique at 305 K with ammonium sulfate and PEG 400 as precipitants. VS crystals diffract to 2.8 Å and belong to space group P212121, with unit-cell parameters a = 82.3, b = 89.6, c = 136.2 Å. The selenomethionyl VS crystal was nearly isomorphous with the VS crystal.
Straightforward Regio- and Diastereoselective Synthesis, Molecular Structure, Intermolecular Interactions and Mechanistic Study of Spirooxindole-Engr…
2021
Straightforward regio- and diastereoselective synthesis of bi-spirooxindole-engrafted rhodanine analogs 5a–d were achieved by one-pot multicomponent [3 + 2] cycloaddition (32CA) reaction of stabilized azomethine ylide (AYs 3a–d) generated in situ by condensation of L-thioproline and 6-chloro-isatin with (E)-2-(5-(4-chlorobenzylidene)-2,4-dioxothiazolidin-3-yl)-N-(2-morpholinoethyl)acetamide. The bi-spirooxindole-engrafted rhodanine analogs were constructed with excellent diastereo- and regioselectivity along with high chemical yield. X-ray crystallographic investigations for hybrid 5a revealed the presence of four contiguous stereocenters related to C11, C12, C19 and C22 of the spiro struct…
Synthesis, benzodiazepine receptor binding and molecular modelling of isochromeno[4,3-c]pyrazol-5(1H)-one derivatives
2012
Abstract A series of isochromeno[4,3-c]pyrazole-5(1H)-one derivatives 7b–h were prepared and tested at 10 μM for their ability to displace specific [3H]flunitrazepam from bovine brain membranes. The substitution pattern of the above derivatives was shown to influence the receptor affinity. The most active compound of the series was 7e, showing a 54% inhibition of [3H]flunitrazepam binding. Compounds 7a–d,i were compared with the known isomers chromeno[4,3-c]pyrazole-4(1H)-ones 14a–d,i, showing that the isochromene/chromene isomerism influences the activity.
Control of N-Heterocyclic Carbene Catalyzed Reactions of Enals: Asymmetric Synthesis of Oxindole-γ-Amino Acid Derivatives.
2017
A strategy to control the switch between a non‐cycloaddition reaction and a cycloaddition reaction of enals, using N‐heterocyclic carbene (NHC) catalyisis, has been developed. The new scalable protocol leads to γ‐amino‐acid esters bearing a tetrasubstituted stereocenter in good yields and high stereoselectivities by homo‐Mannich reactions of enals and isatin‐derived ketimines. By simply changing the N‐ketimine substituent to an ortho‐hydroxy phenyl group, the corresponding spirocyclic oxindolo‐γ‐lactams are obtained. peerReviewed
Dual Substituent Parameter Modeling of Theoretical, NMR and IR Spectral Data of 5-Substituted Indole-2,3-diones
2002
Correlations of AM1 and PM3 theoretical data, 13C-NMR substituent chemical shifts (13C-SCS) and IR carbonyl group wave numbers [ν(C3â•ÂO)] were studied using dual substituent parameter (DSP) models for 5-substituted indole-2,3-diones. For the C7 atom a reverse substituent effect attributed to extended À-polarization was observed. On the other hand, the DSP approaches for the C3 atom showed normal substituent effects with some contribution of reverse effect supported strongly by 13C-SCS correlations. In the ν(C3â•ÂO) and p(C3â•ÂO) DSP correlations the field effect contribution predominates over the resonance effect, which justifies the using of earlier suggested vibrational cou…
Structural Basis and Enzymatic Mechanism of the Biosynthesis of C9- from C10-Monoterpenoid Indole Alkaloids
2009
Cutting carbons: The three-dimensional structure of polyneuridine aldehyde esterase (PNAE) gives insight into the enzymatic mechanism of the biosynthesis of C(9)- from C(10)-monoterpenoid indole alkaloids (see scheme). PNAE is a very substrate-specific serine esterase. It harbors the catalytic triad S87-D216-H244, and is a new member of the alpha/beta-fold hydrolase superfamily. Its novel function leads to the diversification of alkaloid structures.
Bond-based 3D-chiral linear indices: Theory and QSAR applications to central chirality codification
2008
The recently introduced non-stochastic and stochastic bond-based linear indices are been generalized to codify chemical structure information for chiral drugs, making use of a trigonometric 3D-chirality correction factor. These improved modified descriptors are applied to several well-known data sets to validate each one of them. Particularly, Cramer's steroid data set has become a benchmark for the assessment of novel quantitative structure activity relationship methods. This data set has been used by several researchers using 3D-QSAR approaches such as Comparative Molecular Field Analysis, Molecular Quantum Similarity Measures, Comparative Molecular Moment Analysis, E-state, Mapping Prope…