Search results for "Indole"
showing 10 items of 570 documents
Synthesis of 7-Pentafluorophenyl-1H-indole: An Anion Receptor for Anion–π Interactions
2014
7-Pentafluorophenyl-1H-indole has the potential to be a key compound for the investigation of anion–π interactions in solution. Unfortunately, it was not possible to obtain it by aryl–aryl coupling reaction. Finally, it has been prepared by Bartoli indole synthesis. The key compound as well as analogues were submitted to preliminary studies of anion binding. Single crystals of two key receptors were obtained.
Natural Product Synthesis on Polymeric Supports—Synthesis and Biological Evaluation of an Indolactam Library
1999
Potent activators of protein kinase C in fibroblasts: This property was determined for several indolactam V analogues (1) with a new cell-based assay system. This tumor-promoting indole alkaloid and analogues thereof can be synthesized efficiently on the solid phase. The key steps of the combinatorial approach are a regioselective amination of the indole ring and an enantioselective enzymatic reaction.
An efficient and practical synthesis of [2-11C]indole via superfast nucleophilic [11C]cyanation and RANEY® Nickel catalyzed reductive cyclization
2015
A rapid method for the synthesis of carbon-11 radiolabeled indole was developed using a sub-nanomolar quantity of no-carrier-added [(11)C]cyanide as radio-precursor. Based upon a reported synthesis of 2-(2-nitrophenyl)acetonitrile (), a highly reactive substrate 2-nitrobenzyl bromide () was evaluated for nucleophilic [(11)C]cyanation. Additionally, related reaction conditions were explored with the goal of obtaining of highly reactive 2-(2-nitrophenyl)-[1-(11)C]acetonitrile () while inhibiting its rapid conversion to 2,3-bis(2-nitrophenyl)-[1-(11)C]propanenitrile (). Next, a RANEY® Nickel catalyzed reductive cyclization method was utilized for synthesizing the desired [2-(11)C]indole with h…
Understanding C C bond formation in polar reactions. An ELF analysis of the Friedel Crafts reaction between indoles and nitroolefins
2013
[EN] The Friedel-Crafts (FC) reaction of N-methyl indole 1 with nitroethylene 2 has been studied using DFT methods at the B3LYP/6-31+G** level in order to characterize the bonding changes along the C-C bond-formation process in polar reactions. For this FC reaction a two-step mechanism has been found. The first step is associated with the C-C bond formation between the most electrophilic centre of nitroethylene and the most nucleophilic centre of N-methyl indole, to yield a zwitterionic intermediate IN. The second step corresponds to an intramolecular proton transfer process at IN, regenerating the aromatic system present at the indole. Despite the high electrophilic character shown by nitr…
Indole-substituted 2,4-diamino-5,8-dihydropyrido[2,3-d]pyrimidines from one-pot process and evaluation of their ability to bind dopamine receptors
2018
A series of novel 7-indole substituted 2,4-diamino-5,8-dihydropyrido[2,3-d]pyrimidine analogous to the 2,4-diaminopteridine core were synthesized by the three-component one-pot cyclocondensation between 2,4,6-triaminopyrimidine, 3-(2-cyanoacetyl)indole and aromatic aldehydes. The reactions, which exhibited good performance, proceeded in EtOH using indium (III) chloride as catalyst under microwave irradiation, in short reaction times. On the basis of certain structural similarity of these compounds with known ligands of the D2 dopamine receptors (D2DR), the study of these compounds as possible ligands of dopamine D2 and D1 receptors was carried out. Three of them showed moderate affinity to …
Two-Step Route to Indoles and Analogues from Haloarenes: A Variation on the Fischer Indole Synthesis
2012
In a new variation on the Fischer indole synthesis, readily available haloarenes are converted into a wide range of indoles in just two steps by halogen-magnesium exchange and quenching with di-tert-butyl azodicarboxylate, followed by reaction with aldehydes or ketones under acidic conditions. The protocol, which is readily extended to the preparation of indole isosteres, 4- and 6-azaindoles and thienopyrroles, obviates the need to prepare potentially toxic aryl hydrazines, simultaneously avoiding undesirable anilines such as naphthylamines.
Heterologous expression of aRauvolfiacDNA encoding strictosidine glucosidase, a biosynthetic key to over 2000 monoterpenoid indole alkaloids
2002
Strictosidine glucosidase (SG) is an enzyme that catalyses the second step in the biosynthesis of various classes of monoterpenoid indole alkaloids. Based on the comparison of cDNA sequences of SG from Catharanthus roseus and raucaffricine glucosidase (RG) from Rauvolfia serpentina, primers for RT-PCR were designed and the cDNA encoding SG was cloned from R. serpentina cell suspension cultures. The active enzyme was expressed in Escherichia coli and purified to homogeneity. Analysis of its deduced amino-acid sequence assigned the SG from R. serpentina to family 1 of glycosyl hydrolases. In contrast to the SG from C. roseus, the enzyme from R. serpentina is predicted to lack an uncleavable N…
Entropy-controlled diastereoselectivity in the photocyclization of rigid derivatives of o-allylaniline.
2002
Two rigid derivatives of o-allylaniline, namely 8-allyl-2-phenyl-1,2,3,4-tetrahydroquinoline (1b) and 7-(trans-2-cinnamyl)-2-methylindoline (1c), have been chosen as suitable systems to study the potential stereoselectivity of the photocyclization process. Photolysis of 1b leads to a mixture of diastereomeric lilolidines 4 (trans/cis), while 1cproduces a mixture of 4 (trans/cis) and the tetrahydropyrrolo[3,2,1-hi]indole derivatives 5 (trans/cis). To disclose whether the diastereoselectivity could be entropy dependent, photolysis of 1b and 1c has been performed at several temperatures. In both cases, linear relationships have been observed when ln(k(t)/k(c)) (the relative reaction rate const…
High-performance liquid chromatographic, capillary electrophoretic and capillary electrophoretic–electrospray ionisation mass spectrometric analysis …
2002
Systems for efficient separation of selected alkaloid groups by high performance liquid chromatography (HPLC), capillary electrophoresis (CE) and capillary electrophoresis coupled with electrospray ionisation mass spectrometry (CE-ESI-MS) are described. The optimized HPLC system was applied for the separation of 23 standard indole alkaloids as well as for qualitative and quantitative analyses of crude alkaloid extracts of Rauvolfia serpentina X Rhazya stricta hybrid cell cultures. The developed conditions for CE analysis proved to be efficient for separation of mixtures of standard indole and beta-carboline alkaloids. The described buffer system is also applicable in the combination of CE w…
Theoretical study of spiropyran-merocyanine thermal isomerization.
2004
Abstract Quantum mechanical computations at DFT level were carried out on the processes involved in the thermal reaction SP ⇆ ME, where SP is the nitro-substituted spirobenzopyran (1 ′ ,3 ′ -dihydro-1 ′ ,3 ′ ,3 ′ -trimethyl-6-nitro-spiro[2H-1-benzopyran-2,2 ′ - [2H]indole]) in the closed form and ME is the corresponding open form. A detailed theoretical description of the overall reaction is reported along with the thermodynamic parameters for all intermediates and transition states. The obtained activation energy value is in agreement with the available experimental data in solution.