Search results for "Indole test"
showing 10 items of 126 documents
Zur Reaktion vonE/Z-N-Benzolsulfonyl-3(2-methoxyvinyl)-indol mit Carbo- und Heterodienophilen: NeueDiels-Alder-Addukte aus der Indol- bzw. Carbazol-R…
1987
E/Z-Benzenesulfonyl-3(2-methoxyvinyl)-indole1 reacts viaDiels-Alder type mechanism with dimethyl acetylendicarboxylate, N-phenyltriazolindione and diethyl mesoxalate to give new cycloadducts2–5 with [b]annellated indole structures.
The reactivity of 2-vinylindoles with dimethyl acetylenedicarboxylate
1984
Abstract The overall rates of reaction of 1-substltuted-1- (1-methyl-2-indolyl)ethenes with dimethyl acetylenedicarboxylate are considerably lower than those of the corresponding 2-vinyl- pyrroles. Steric interaction between the N-methyl group on the indole ring and the 1-substituent on the ethenyl group prevents the diene system adopting a coplanar cisoid configuration and, thereby, inhibits the π4 + π2 cycloaddition reaction of the system with dimethyl acetylenedicarboxylate. Under such conditions, the indolylethene preferentially undergoes a Michael addition reaction at the 3-position. The π4 + π2 cycloaddition reaction is promoted at elevated temperatures. No evidence was found for a Co…
ChemInform Abstract: Cross-Dehydrogenative Couplings Between Indoles and β-Keto Esters: Ligand-Assisted Ligand Tautomerization and Dehydrogenation vi…
2014
Cross-dehydrogenative coupling reactions between β-ketoesters and electron-rich arenes, such as indoles, proceed with high regiochemical fidelity with a range of β-ketoesters and indoles. The mechanism of the reaction between a prototypical β-ketoester, ethyl 2-oxocyclopentanonecarboxylate, and N-methylindole has been studied experimentally by monitoring the temporal course of the reaction by (1)H NMR, kinetic isotope effect studies, and control experiments. DFT calculations have been carried out using a dispersion-corrected range-separated hybrid functional (ωB97X-D) to explore the basic elementary steps of the catalytic cycle. The experimental results indicate that the reaction proceeds v…
Capillary zone electrophoresis of alkaloids
1998
Abstract A comprehensive discussion of important aspects for the analysis of alkaloids by capillary zone electrophoresis (CZE) is given. The influence of structure on the electrophoretic mobility (EM) of indole alkaloids was investigated using a running buffer which is generally applicable to the CZE analysis of alkaloids. The EM, which at the applied conditions was mostly dependent on the size and shape of the solvated analyte ions, was additionally affected by the presence of hydrogen bonds or ion–dipole interactions between protonated and unprotonated alkaloids of the same species. This could be derived from the existence of alkaloidal dimer cluster ions [2M+H]+ when mass spectrometry wa…
General approach for the analysis of various alkaloid classes using capillary electrophoresis and capillary electrophoresis-mass spectrometry
1997
Abstract The analysis of various alkaloid classes employing capillary electrophoresis (CE) and on-line combined CE-mass spectrometry (CE-MS) is described. A CE method is presented for the analysis of alkaloids without derivatisation or purification. The separation of four different groups of alkaloids consisting of monoterpenoid indole alkaloids, protoberberines/benzophenanthridines, β-carboline alkaloids, and isoquinolines from poppy by free zone capillary electrophoresis has been obtained using a 1:1 mixture of 100 mmol 1 −1 ammonium acetate (pH 3.1) and acetonitrile. The influence of alkaloid structure on the electrophoretic mobility is discussed. The CE-MS reconstructed total ion curren…
Partialsynthese neuer Ergolinderivate aus Clavinalkaloiden, 3. Mitt.1) O-Acyl- und O-Alkyl-1,6-dimethyl-8-hydroxymethyl-ergol-9-ene
1983
Elymoclavin (1), Lysergol (2) und O-Acyl-lysergole werden in flussigem Ammoniak mit Kalium und Methyliodid zunachst am Indolstickstoff methyliert. Durch Variation der Versuchsbedingungen werden 1 und 2 sekundar auch an der Hydroxylgruppe methyliert. Aus 1-Methyl-lysergol (3) sind daher nach der gleichen Methode mit verschiedenen Alkyliodiden 1-Methyl-lysergol-ether darstellbar. Dagegen gelingt die Ethersynthese nach Williamson aus 17-Halogen-ergolenen nicht. Partial Synthesis of New Ergoline Dervatives from Clavine Alkaloids, III: O-Acyl-and O-Alkyl-1,6-dimethyl-8-(hydroxymethyl)ergol-9-enes Elymoclavine (1), lysergole (2) and O-acyllysergoles are primarily methylated at the indole nitrogen…
ChemInform Abstract: Microwave-Assisted Synthesis of 1,3-Disubstituted β-Carbolines from α-(Alkylideneamino)nitriles and Gramine.
2012
The title reaction produces indole derivatives of type (V) whose cyclization leads to formation of the desired alkaloid skeletons.
ChemInform Abstract: Progress in Palladium-Based Catalytic Systems for the Sustainable Synthesis of Annulated Heterocycles: A Focus on Indole Backbon…
2012
A survey highlighting the most recent palladium catalytic systems produced and their performances for progress in direct synthesis of indole backbones by heterocarbocyclization of reactive substrates is provided. The discussion is developed in relation with the principles of sustainable chemistry concerning atom and mass economy. In this respect, the general convergent character of the syntheses is of particular interest (one-pot, domino, cascade or tandem reactions), and the substrates accessibility and reactivity, together with the final waste production, are also important. This critical review clearly indicates that the development of ligand chemistry, mainly phosphines and carbenes, in…
Connecting Electron-Deficient and Electron-Rich Aromatics to Support Intermolecular Interactions in Crystals
2015
Five compounds bearing electron-deficient pentafluorophenyl as well as electron-rich (salicylate or indole) aromatic moieties connected by amide or ester linkages were investigated by X-ray diffraction. In the crystals, various interactions (π–π, lone pair–π) between the different aromatic units are important structure controlling factors in addition to the stronger inter- or intramolecular hydrogen bonds induced by the amide and ester moieties. The hydrogen bonding leads to polymeric and macrocyclic assembly of the molecular building blocks.
Diels-Alder Reactions ofin situ generated N-benzoylindolo-2,3-quinodimethane with carbodienophiles
1993
The indolo-2,3-quinodimethane (5), generated from 2,3-bis(bromomethyl)indole (4), was trapped with unsymmetrical carbodienophiles or N, N′-p-phenylenedimaleimide to furnish the 1,2,3,4-tetrahydrocarbazoles (6–9). [4 + 2]-Cycloaddition of 5 with tetracyanoethylene gave rise to the tetracyanocarbazole (10) and a subsequent product 11a or 11b. The Diels-Alder reaction of 5 with divinyl sulfone was regiospecific within the detection limits of HPLC analysis. Similarly, the reaction of 5 with N, N′-p-phenylenedimaleimide yielded solely the stereoisomer 9.