- Cyclopropenones in the synthesis of indolizidine, pyrrolo[2,1-a]isoquinoline and indolizino[8,7-b]indole alkaloids
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An attempted synthesis of the indolizidine natural product castanospermine resulted in the successful addition of cyclopropenone to a sugar-derived poly-hydroxylated cyclic imine to give an indolizidinone product, but with the installation of an extra hydroxy group at the castanospermine 8a-bridgehead position. This was also observed in our previous approach to the australine and hyacinthacine pyrrolizidine natural products. The same oxidative phenomenon occurred during the synthesis of pyrrolo[1,2-a]isoquinolines from the reaction of aldimine dihydroisoquinolines with cyclopropenones, whereas ketimine based dihydroisoquinolines gave pyrrolo[1,2-a]isoquinolines without bridgehead oxidation. These results may have some significance for the origins of the bridgehead hydroxy natural products jenamidine B1/B2, clazamycin A/B and legonmycin A/B. The precursor cyclic aldimine for the synthesis of the indolizino[8,7-b]indoles gave dimeric indolizino[8,7-b]indoles, whereas the corresponding cyclic ketimines behaved as expected and gave the indolizino[8,7-b]indole core after reaction with cyclopropenones.
- Jamshaid, Faisal,Kondakal, Vishnu V.R.,Newman, C. Declan,Dobson, Rhianne,Jo?o, Heidi,Rice, Craig R.,Mwansa, Joseph M.,Thapa, Bimod,Hemming, Karl
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supporting information
(2020/09/18)
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- Solution phase and nanoparticular biosynthetically inspired interconnections in the canthin-6-one β-carboline series and study of phenotypic properties on C. elegans
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Based on the biosynthetic line of canthin-6-one alkaloids from their simple precursors such as tryptamine, the present work is focused on the study of alternative protocol of the Bischler-Napieralski reaction and has led to a full coverage of the different biosynthetic intermediates. Nanoparticles were also prepared as mimics of biosynthetic assembly lines and some interesting biological results in term of chemical ecology are also reported. Canthin-6-one, a particular representative β-carboline alkaloid, was targeted for synthesis keeping in mind its biosynthetic origin. In fact, several biosynthetic intermediates were synthesized and nanoparticular mimicry of key steps was also achieved permitting further evaluation of biological properties for this class of alkaloids. Copyright
- Cebrian-Torrejon, Gerardo,Mackiewicz, Nicolas,Vazquez-Manrique, Rafael P.,Fournet, Alain,Figadere, Bruno,Nicolas, Julien,Poupon, Erwan
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p. 5821 - 5828
(2013/09/23)
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- USE OF CANTHIN-6-ONE AND ITS ANALOGS IN THE TREATMENT OF MYCOBACTERIA-LINKED PATHOLOGIES ( amended
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The present invention relates to the use, for the preparation of a medicament intended for the treatment or the prevention of pathologies linked to, or caused by mycobacteria, of at least one of the compounds of the following formula (I): in which B represents in particular a nitrogen atom, and R1, R2, R3, R4, R5, R6, R7 and R8 represent in particular a hydrogen atom.
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Page/Page column 7
(2011/04/18)
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- Palladium asymmetric reduction of β-carboline imines mediated by chiral auxiliaries assisted by microwave irradiation
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An alternative synthetic approach for the introduction of chirality in β-carboline moiety through in situ reduction of N-acyliminium ion intermediates generated from imine 2 and chloroformate of 8-phenylmenthyl as chiral auxiliary was achieved. The method applied microwave-assisted irradiation and used PdCl2/Et3SiH protocol as a mild reducing agent, which decreased reaction times to minutes when compared to the conventional thermal reactions. The diastereoselectivity (4-12:1) of the reduction produced R-amines, which were assigned after chiral auxiliary removal and spectroscopic data compared to products obtained from Noyori asymmetric hydrogenation catalyst.
- Espinoza-Moraga, Marlene,Caceres, Ana Gloria,Santos, Leonardo Silva
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scheme or table
p. 7059 - 7061
(2010/02/28)
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- Novel supramolecular palladium catalyst for the asymmetric reduction of imines in aqueous media
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A novel approach to the asymmetric reduction of dihydro-β-carboline derivatives to the corresponding tetrahydro-β-carbolines is described based on the supramolecular lyophilized complex formed from β-cyclodextrin/ imines as an enzyme mimetic and palladium hydride as the reducing agent. The methodology allowed us to develop a short and efficient preparation of (R)-harmicine and (R)-deplancheine alkaloids in high overall yields and ee of 89 and 90%, respectively.
- Da Silva, Wender A.,Rodrigues Jr., Manoel T.,Shankaraiah,Ferreira, Renan B.,Andrade, Carlos Kleber Z.,Pilli, Ronaldo A.,Santos, Leonardo S.
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supporting information; experimental part
p. 3238 - 3241
(2010/02/28)
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- Construction of the "left domain" of haplophytine
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(Chemical Equation Presented) Left of the middle: Synthesis of the "left" structural domain (2) of haplophytine (1) features a stereoselective construction of its sterically congested carbon-carbon bond (C9′-C15) and an efficient cascade sequence involvin
- Nicolaou,Majumder, Utpal,Roche, Stephane Philippe,Chen, David Y.-K.
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p. 4715 - 4718
(2008/02/08)
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- Extraction, hemisynthesis, and synthesis of canthin-6-one analogues. Evaluation of their antifungal activities
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Zanthoxylum chiloperone var. angustifolium was investigated. Alkaloids 1-3 from the canthin-6-one series were characterized. Derivatives 7-28 were prepared by hemisynthesis or total synthesis. All compounds were tested for in vitro antifungal activities against five pathogenic fungal strains. Analogues of canthin-6-one did not show better antifungal activities. 2005 American Chemical Society and American Society of Pharmacognosy.
- Soriano-Agaton, Flor,Lagoutte, Delphine,Poupon, Erwan,Roblot, Francois,Fournet, Alain,Gantier, Jean-Charles,Hocquemiller, Reynald
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p. 1581 - 1587
(2008/09/17)
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- (PhO)3P·Cl2-promoted bischler-napieralski-type cyclization: A mild access to β-carbolines
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A novel mild access to the β-carboline skeleton is described. The reaction is a Bischler-Napieralski-type cyclocondensation, promoted by (PhO)3P·Cl2, which is performed in dichloromethane at -30 °C. The products are easily obtained i
- Spaggiari, Alberto,Davoli, Paolo,Blaszczak, Larry C.,Prati, Fabio
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p. 661 - 663
(2007/10/03)
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- The chemistry of indoles. CIII. Simple syntheses of serotonin, N-methylserotonin, bufotenine, 5-methoxy-N-methyltryptamine, bufobutanoic acid, N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine, and lespedamine based on 1-hydroxyindole chemistry
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Application of regioselective nucleophilic substitution reactions of 1-hydroxytryptamines to novel and simple syntheses of serotonin (1a), N-methylserotonin (1b), bufotenine (1c), 5-methoxy-N-methyltryptamine (2a), bufobutanoic acid (3a), N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine (4), and lespedamine (5) are described. Effective syntheses of 5-benzyloxytryptamine and 1-methoxy-2-oxindoles are also reported.
- Somei,Yamada,Kurauchi,Nagahama,Hasegawa,Yamada,Teranishi,Sato,Kaneko
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- The first total synthesis of bufobutanoic acid by two routes based on nucleophilic substitution reaction on indole nucleus
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Regioselective nucleophilic substitution reaction of 1- hydroxytryptamines led to establish two novel routes for the first synthesis of bufobutanoic acid. An effective synthesis of 5-benzyloxytryptamine from tryptamine is also reported.
- Kurauchi, Takashi,Nagahama, Yoshiyuki,Hasegawa, Masakazu,Yamada, Koji,Somei, Masanori
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p. 1017 - 1019
(2007/10/03)
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- Reduction of Lactams and Thiolactams by Sodium Borohydride: Application in the Synthesis of Some Alkaloids
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Lactams 1a-8a and thiolactams 1b-8b,9a,10b-12b and 13 could be reduced to their corresponding amines in 70-98percent yield by using borohydide-tert-butyl alcohol-methanol mixtures under reflux.Even the vinylogous amide 19 underwent reduction to afford dep
- Mandal, S. B.,Giri, V. S.,Sabeena, M. S.,Pakrashi, S. C.
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p. 4236 - 4241
(2007/10/02)
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