- Acid-Base and Spectral Properties of β-Carbolines. Part 2. Dehydro and Fully Aromatic β-Carbolines
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The absorption and fluorescence spectra of a set of dehydro and fully aromatic β-carboline (9H-pyridoindole) derivatives have been investigated in aqueous solutions of varying acidity.Within the pH-range, cationic (nitrogen protonation) and neutral species are evidenced from both absorption and fluorescence spectra.Additional zwitterionic species can also be detected from the fluorescence spectra.In highly basic media, outside the pH-range, anionic species (pyrrolic nitrogen deprotonation) are formed.Ground state ionization constants for the differentacid-base equilibria involving these species have been determined spectrophotometrically at 25 deg C.Lowest excited singlet state pKas have been estimated from the Foerster-Weller cycle.The influence of structural variations on the spectra and on the acid-base properties of these compounds is discussed.
- Balon, Manuel,Hidalgo, Jose,Guardado, Pilar,Munoz, Maria A.,Carmona, Carmen
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- Further investigation of harmicines as novel antiplasmodial agents: Synthesis, structure-activity relationship and insight into the mechanism of action
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The rise of the resistance of the malaria parasite to the currently approved therapy urges the discovery and development of new efficient agents. Previously we have demonstrated that harmicines, hybrid compounds composed from β-carboline alkaloid harmine
- Marinovi?, Marina,Poje, Goran,Perkovi?, Ivana,Fontinha, Diana,Prudêncio, Miguel,Held, Jana,Pessanha de Carvalho, Lais,Tandari?, Tana,Vianello, Robert,Raji?, Zrinka
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- A new approach to 1-substituted β-carbolines and isoquinolines utilizing tributyl[(Z)-2-ethoxyvinyl]stannane as a C-3,C-4 building block
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Starting from readily available indole-2-carboxylic acids, 1-substituted β-carbolines (among them the alkaloids harmane and isoharmine) are readily obtained via the corresponding 2-acylindoles, bromination at C-3, followed by a one-pot Stille cross-coupling with tributyl[(Z)-2-ethoxyvinyl]stannane, and ring closure with ammonium acetate. 1-Substituted isoquinolines are available in an analogous manner starting from 2-bromobenzoic acid.
- Kamlah, Alexandra,Lirk, Florian,Bracher, Franz
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p. 837 - 845
(2016/01/20)
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- Structural development of canthin-5,6-dione moiety as a fluorescent dye and its application to novel fluorescent sensors
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Canthin-5,6-dione is a common structure of the fluorescent natural products amarastelline A and nigakinone. Here, we synthesized various derivatives, and studied their fluorescence properties. The effects of substituent groups at the N3-, 4- and 10-positions were clarified. N3-Substitution influenced the solvent-dependent fluorescent change by modulating tautomerization between canthin-5,6-dione and the 5-hydroxy-6-one form. 10-Substitution also influenced the fluorescence, especially in aqueous solution, in combination with N3-substitution. Among the synthesized compounds, 5 showed an ‘OFF-ON-OFF’-type fluorescence change with increase of pH, and therefore served as a novel fluorescent sensor for a specific range of pH. Our findings suggest that canthin-5,6-dione should be useful as a fluorophore moiety for fluorescent labeling of biomolecules and for development of fluorescent probes and sensors.
- Yokoo, Hidetomo,Ohsaki, Ayumi,Kagechika, Hiroyuki,Hirano, Tomoya
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p. 5872 - 5879
(2016/09/07)
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- Microwave-Assisted Synthesis of Tetrahydro-β-carbolines and β-Carbolines
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A microwave-mediated Pictet-Spengler procedure utilizing 1,2-dichloroethane (DCE) and trifluoroacetic acid (TFA) was developed to provide tetrahydro-β-carboline salts in high yields. Reactions are complete in 20 minutes or less and the product precipitates from solution in high yields and purity, negating the need for liquid-liquid extraction or column chromatography. This method tolerates a wide range of functionality and can be performed on milligram to gram scales. A subsequent microwave-mediated aromatization of the synthesized tetrahydro-β-carbolines to β-carbolines was also developed utilizing catalytic Pd/C. The aromatization is complete in 60 min or less with most substrates requiring minimal purification. A microwave-assisted Pictet-Spengler procedure was developed to afford tetrahydro-β-carboline salts in high yields with no liquid-liquid extraction or chromatography required. A subsequent microwave-assisted aromatization procedure was also developed to provide β-carbolines in high yields requiring limited purification.
- Eagon, Scott,Anderson, Marc O.
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p. 1653 - 1665
(2015/10/05)
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- Structure-activity relationship study of beta-carboline derivatives as haspin kinase inhibitors
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Haspin is a serine/threonine kinase that phosphorylates Thr-3 of histone H3 in mitosis that has emerged as a possible cancer therapeutic target. High throughput screening of approximately 140,000 compounds identified the beta-carbolines harmine and harmol as moderately potent haspin kinase inhibitors. Based on information obtained from a structure-activity relationship study previously conducted for an acridine series of haspin inhibitors in conjunction with in silico docking using a recently disclosed crystal structure of the kinase, harmine analogs were designed that resulted in significantly increased haspin kinase inhibitory potency. The harmine derivatives also demonstrated less activity towards DYRK2 compared to the acridine series. In vitro mouse liver microsome stability and kinase profiling of a representative member of the harmine series (42, LDN-211898) are also presented.
- Cuny, Gregory D.,Ulyanova, Natalia P.,Patnaik, Debasis,Liu, Ji-Feng,Lin, Xiangjie,Auerbach, Ken,Ray, Soumya S.,Xian, Jun,Glicksman, Marcie A.,Stein, Ross L.,Higgins, Jonathan M.G.
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scheme or table
p. 2015 - 2019
(2012/04/05)
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- 6-Hydroxy- and 6-methoxy-β-carbolines as acetyl- and butyrylcholinesterase inhibitors
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In the course of studies directed toward the discovery of novel acetyl- and butyrylcholinesterase (AChE and BChE) inhibitors for the treatment of Alzheimer's disease, we focused on β-carbolines (BCs). 6-Oxygenated β-carboline and β-carbolinium derivatives based on the serotonin template were synthesized and tested in vitro for their ability to inhibit AChE and BChE, respectively. Particularly the carbolinium salts, which can be formed by intracerebral methylation out of the tertiary-BC prodrugs, show inhibitory activity levels reaching those of galantamine, physostigmine, and rivastigmine.
- Schott, Yvonne,Decker, Michael,Rommelspacher, Hans,Lehmann, Jochen
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p. 5840 - 5843
(2007/10/03)
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- β-Carbolines as specific inhibitors of cyclin-dependent kinases
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Harmine (3), 7-fluoro-1-methyl β-carboline (35) and 1-(5-methyl-imidazol-4-yl) β-carboline (41) were potent and specific inhibitors of cyclin-dependent kinases. The degree of aromaticity of the tricyclic ring and the positioning of substituents are important for inhibitory activity. While most β-carbolines inhibited CDK2 and CDK5 to the same extent, selective inhibition against CDK2 was observed in 1-(2-chlorophenyl)- (12), 1-(2-fluorophenyl)- (15), and 1-(2-chloro-5-nitrophenyl)- (28) β-carbolines.
- Song, Yongcheng,Wang, Jian,Teng, Su Fern,Kesuma, Djohan,Deng, Yu,Duan, Jinao,Wang, Jerry H.,Qi, Robert Zhong,Sim, Mui Mui
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p. 1129 - 1132
(2007/10/03)
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- Isoharmine revisited: Thermal rearrangement of a 3-cyanomethyl-2- vinylindole
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Thermolysis of 2-vinylindole derivative (1) led to indolylacrylonitrile (6) instead of β-carboline alkaloid isoharmine (4). Latter was prepared by following the conventional method and was fully characterized.
- Sapi, Janos,Patigny, Dominique,Laronze, Jean-Yves
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p. 361 - 364
(2007/10/03)
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