- Synthesis of Alkyl-Substituted Pyridines by Directed Pd(II)-Catalyzed C-H Activation of Alkanoic Amides
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A general alkylation protocol for substituted iodopyridines was developed (32 examples, 44-97% yield). The reaction is based on the Pd(II)-catalyzed C-H activation of 8-aminoquinoline-derived alkanoic amides and it employs a catalyst cocktail of Pd(OAc)2 (10 mol%), NaI (30 mol%), and (BuO)2POOH (20 mol%), with Ag2CO3 as base.
- Hu, Peng,Bach, Thorsten
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p. 2853 - 2857
(2015/12/18)
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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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- β-Carboline alkaloids, part 6: Total synthesis of the phosphodiesterase inhibitor infractine
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The alkaloid infractine was prepared by Heck-olefination of the triflate 4 with methyl acrylate followed by catalytic hydrogenation. Attempted alkinylation of 1-chloro-β-carboline with ethyl propiolate resulted in exclusive 1,4-addition to the indole nitrogen.
- Bracher,Hildebrand
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p. 182 - 183
(2007/10/02)
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- Synthesis of Manzamine C, Infractine and 6-Hydroxyinfractine
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Manzamine C (1), a β-carboline alkaloid with antitumor activity isolated from the marine sponge Haliclona sp. was synthesized.The dilithium derivative of 5-hexynoic acid (6) was alkylated with 7 to give after esterification the methyl 10-hydroxy-5-decynoate (8).The tosylate of 8 was converted into the azide 9 which could be selectively hydrogenated with Lindlar palladium catalyst to give the amino ester 10.Saponification of 10 and acylation with (Boc)2O yielded 11, which was converted with pentafluorophenol into 12.Removal of the Boc group in 12 gave an amino ester as intermediate, which cyclized immediately under high dilution conditions to give the lactam 13 in high yield.Reduction of 13 with LiAlH4 produced the macrocyclic amine 4.The β-carboline part of 1 was prepared by condensation of N-benzyltryptamine 14 with the formylacetic acid equivalent 15 to give 16.Dehydrogenation of 16 with Pd-on-carbon catalyst led to the orthoester 17, which could be converted into the methyl ester 5 in high overall yield.The 4-(dimethylamino)pyridine-catalyzed substitution of the methyl ester function in 5 by the amine 4 gave the amide 29.The analogous reaction of 5 with pyrrolidine or with azacyclotridecane yielded 30 and 31.Reduction of these three amides with LiAlH4 produced 1, 2 and 3.The spectroscopic properties of 1 were identical with those of natural manzamine C. - Condensation of 14 or N-benzyl-5-(benzyloxy)tryptamine (19) with aldehyde 18 yielded the products 20 and 21, which could be dehydrogenated to furnish 22 and 23.From these the methyl esters 24 and 25 with properties identical to those of the known β-carboline alkaloids infractine and 6-hydroxyinfractine could be obtained.
- Nowak, Wolfgang,Gerlach, Hans
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p. 153 - 160
(2007/10/02)
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