Search results for "Indole"
showing 10 items of 570 documents
Alkylation of ambident indole anion in ionic liquids
2007
AbstractAlkylation of indole salts in different ionic liquids is reported. Ionic liquids increase the alkylation reaction rate of ambident indole anion and reduce the effects of counter ions and/or additives, the alkylation reaction rates being independent of the presence of small amounts of protic solvents or water.
Studies on the synthesis of pentacyclic strychnos indole alkaloids. photocyclization of n-chloroacetyl-1,2,3,4,5,6-hexahydro-1,5-methanoazocino[4,3-b…
1985
Abstract Photocyclization of 2-chloroacetyl-1,2,3,4,5,6-hexahydro-1, 5-methanoazocino[4,3-b]indole ( 5 ) takes place at the indole 4-position to give a 1 ,2 ,3 ,4 , 5 ,6-hexahydro-2 ,11-ethano-1 ,5-methanoazocino [4 , 3-6] indole system. Consequently, the method appears to be unsuitable for constructing the pyrrolidine ring of pentacyclic Strychnos indole alkaloids.
ChemInform Abstract: Palladium-Catalyzed Dehydrogenative β′-Functionalization of β-Keto Esters with Indoles at Room Temperature.
2012
The dehydrogenative β′-functionalization of α-substituted β-keto esters with indoles proceeds with high regioselectivities (C3-selective for the indole partner and β′-selective for the β-keto ester) and good yields under mild palladium catalysis at room temperature with a variety of oxidants. Two possible mechanisms involving either late or early involvement of indole are presented.
Conformation of the umifenovir cation in the molecular and crystal structures of four carboxylic acid salts
2014
The umifenovir salts of maleic, salicylic, glutaric, and gentisic acid as well as the chloroform solvate of the salicylate were prepared. Single crystals of the five compounds were obtained and their molecular and crystal structures determined by X-ray diffraction. In each structure the conformation of phenyl ring with respect to the indole group of the umifenovir moiety is different. The water solubility and melting points of the studied umifenovir salts have been determined.
Screening of oxazepine indole enantiomers by means of high performance liquid chromatography with imprinted polymer stationary phase.
2004
Chromatographic enantiomer separations of different oxazepine indole derivatives were performed using a molecularly imprinted polymer. A 5aR,12R,13S-trans-6,6-dimethyl-12,13-dihydro-6H-5a, 1 3-methanoindolo[2,1-b][1,3]naphthoxazepine-12-carboxamide enantiomerderivative was used as a template and the resultant polymer has shown enantiomer recognition for series of template related compounds. The mechanistic description of the chiral discrimination process is scrutinised, comparing the discrimination between the different conformations and substituents of the oxazepine indoles.
Novel indole alkaloids from cell suspension cultures of aspidosperma quebracho blanco schlecht
1991
Abstract Two novel monoterpenoid indole alkaloids, aspidochibine ( 1 ) and 3-oxo-14,15-dehydrorhazinilam ( 2 ), were isolated from cell suspension cultures of Aspidosperma quebracho blanco Schlecht. Aspidochibine ( 1 ) exhibits a new alkaloid skeleton. The structure of these alkaloids was elucidated by spectroscopic methods.
N-Heterocyclic carbenes from ylides of indolyl-imidazolium, azaindolyl-imidazolium, and indolyl-triazolium salts, and their borane adducts
2014
Abstract Indol-2-yl-imidazolium salts were deprotonated at N1 of the indole ring to give ylides. Their tautomeric N-heterocyclic carbenes (NHCs) were trapped by sulfur to give imidazole-2-thiones. Treatment of the ylides with triethylborane resulted in the formation of zwitterionic borane adducts. An analogous sequence of reactions was performed with 8-azaindol-2-yl-imidazolium salts, which served as precursor to prepare first representatives of a new heterocyclic ring system on reaction of their NHC-tautomers with triethylborane. Similarly, an indol-2-yl-1,2,4-triazolium salt was examined with respect to ylide–NHC tautomerism and trapping reactions. A nucleophilic ring transformation of in…
Partialsynthese neuer Ergolinderivate aus Clavinalkaloiden, 4. Mitt. N-1-, C-2- und N-6-monosubstituierte Agroclavine
1985
Agroclavin (1) wird in flussigem Ammoniak/Kaliumamid mit Alkyliodid am Indolstickstoff alkyliert. 1 last sich mit N-Iodsuccinimid zu 2-Iod-1 (3) umsetzen. Mit der Bromcyan-Methode wird 6-Nor-1 (4b) gewonnen und danach an N-6 alkyliert. Partial Synthesis of New Ergoline Derivatives from Clavine Alkaloids, IV: Agroclavines Monosubstituted at N-1, C-2, and N-6 Agroclavine (1) is alkylated at the indole nitrogen with alkyl iodide in ammonia/potassium amide. It is convertible to 2-iodo-1 (3) with N-iodosuccinimide. Compound 6-nor-1 can be prepared by means of the cyanogen bromide method; alkylation at N-6 is described exemplarily for the ethyl derivative.
Investigations on the content indole-3-acetic spruce needles of healthy and damaged trees of various sites
1993
Summary Surveys were made on the concentration of indole-3-acetic acid (IAA) in spruce trees of various sites. The concentrations of the hormone were specified with a radioimmunoassay after the needle extract had been purified in several steps. The content of IAA in needles of damaged trees was distinctly lower than the content in needles of healthy trees. Another feature was the annual rythm of the IAA content with the maximum of concentration in June. A distinct diurnal course with highest level of concentration during the early afternoon hours was also observed. The diurnal rhythm of the damaged trees was clearly lower. The supposition is that the lower IAA content is responsible for a p…
Mechanism of triplet photosensitized Diels-Alder Reaction between indoles and cyclohexadienes: theoretical support for an adiabatic pathway.
2006
Diels-Alder reactions between indoles (InHs) and 1,3-cyclohexadienes (CHDs) were achieved by using aromatic ketones as photosensitizers. For instance, irradiation of deaerated dichloromethane solutions containing benzoylthiophene (BT, 1 mM), indole (20 mM), and phellandrene (40 mM), in the presence of an acylating agent, led to the N-acetylated Diels-Alder cycloadduct in 46% yield (endo:exo ratio of 1.8:1). Energy transfer from the BT triplet to the CHD gave rise to diene dimers as byproducts. Several combinations of CHDs, InHs, and aromatic ketones were tested; the Diels-Alder reaction was found to be a general process, except when the indole nucleus was substituted at position 2 or 7 and …