- Synthesis and reactivity of dipole-stabilized but unchelated α-aminoorganolithiums
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Two N-methyl-5-lithio-2-pyrrolidinones have been prepared by tin-lithium exchange. These two α-aminoorganolithium compounds that are stabilized by an amide dipole, but not by chelation to the amide carbonyl. Both constitute test cases for comparing the st
- Iula, Donna M.,Gawley, Robert E.
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- Synthesis of aminal-type Lilium candidum alkaloids and lilaline; determination of their relative configuration by the concerted use of NMR spectroscopy and DFT conformational analysis
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We hereby report the synthesis of six racemic alkaloids isolated from Lilium candidum L. Their common structural feature is a five-membered lactam ring which is, in the case of the flavonoid alkaloid lilaline, attached to the molecule's aromatic core, while in the case of the other five compounds, it is connected to the nitrogen atom of a pyrrolinone ring by an aminal function. The syntheses of these natural products were achieved via Mannich-type alkylations through cyclic N-acyliminium ions as intermediates. Besides the synthesis, the so far unexplored stereochemistry of these natural products was determined by a combination of NMR-based proton–proton distance measurements and theoretical conformational analyses carried out at the DFT level.
- Nagy, Sándor,Szigetvári, áron,Ilkei, Viktor,Krámos, Balázs,Béni, Zoltán,Szántay, Csaba,Hazai, László
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- Synthesis of Exo- and Endocyclic Enamides Through Copper-Catalyzed Regioselective Intramolecular N-Halovinylation
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Cross-couplings between amides and 1,2-dihaloalkenes are an efficient and straightforward way to access β-haloenamides which, in turn, can be functionalized into complex, stereodefined enamide motifs. However, the intramolecular version of these cross-couplings, leading to cyclic β-haloenamides, has not been formally studied. In this paper, we report an investigation of factors affecting the efficiency of the reaction and its selectivity between potential exo and endo cyclization products. We demonstrate that exo/endo selectivity is largely determined by ring strain, whether it arises from the size of the resulting ring or from the structure of the starting compound, but that selectivity can also be modulated by varying reaction conditions. Finally, we show that resulting β-haloenamides readily undergo transition metal-catalyzed reactions, making this sequence a viable way to access highly functionalized cyclic enamides.
- Bergeron, Jodrey,Daoust, Benoit,Gilbert, Nicolas,Lambolez, Pierre,Ricard, Simon
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supporting information
(2020/05/04)
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- Exploration of [2 + 2 + 2] cyclotrimerisation methodology to prepare tetrahydroisoquinoline-based compounds with potential aldo-keto reductase 1C3 target affinity
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Tetrahydroisoquinoline (THIQ) is a key structural component in many biologically active molecules including natural products and synthetic pharmaceuticals. Here, we report on the use of transition-metal mediated [2 + 2 + 2] cyclotrimerisation of alkynes to generate tricyclic THIQs with potential to selectively inhibit AKR1C3.
- Santos, Ana R. N.,Sheldrake, Helen M.,Ibrahim, Ali I. M.,Danta, Chhanda Charan,Bonanni, Davide,Daga, Martina,Oliaro-Bosso, Simonetta,Boschi, Donatella,Lolli, Marco L.,Pors, Klaus
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supporting information
p. 1476 - 1480
(2019/08/20)
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- A PROCESS FOR THE PREPARATION OF VIGABATRIN
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The present invention provides a process for the preparation of vigabatrin of formula (I) comprising of dissolving vigabatrin in water, optionally treating with charcoal, filtering and adding an acid to the reaction mass followed by the addition of an organic solvent and then isolating vigabatrin of formula (I) with high purity.
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Page/Page column 5
(2019/10/15)
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- C8-selective biomimetic transformation of 5,7-dihydroxylated flavonoids by an acid-catalysed phenolic Mannich reaction: Synthesis of flavonoid alkaloids with quercetin and (–)-epicatechin skeletons
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We hereby report the biomimetic synthesis of three flavonoid alkaloids, namely 8-(2″-pyrrolidinon-5″-yl)quercetin, 6-(2″-pyrrolidinon-5″-yl)-(–)-epicatechin and 8-(2″-pyrrolidinon-5″-yl)-(–)-epicatechin. These known natural products were prepared via an a
- Ilkei, Viktor,Spaits, András,Prechl, Anita,Müller, Judit,K?ncz?l, árpád,Lévai, Sándor,Riethmüller, Eszter,Szigetvári, áron,Béni, Zoltán,Dékány, Miklós,Martins, Ana,Hunyadi, Attila,Antus, Sándor,Szántay, Csaba,Balogh, Gy?rgy Tibor,Kalaus, Gy?rgy,B?lcskei, Hedvig,Hazai, László
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p. 1503 - 1510
(2017/02/23)
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- Biomimetic synthesis and HPLC-ECD analysis of the isomers of dracocephins A and B
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Starting from racemic naringenin ((±)-1), a mixture of dracocephin A stereoisomers 6-(2″-pyrrolidinone-5″-yl)naringenin (±)-2a-d and its regioisomer, dracocephin B 8-(2″-pyrrolidinone-5″-yl)naringenin (±)-3a-d originally isolated from Dracocephalum rupestre, have been synthesized in a one-pot reaction. The separation of 2a-d and 3a-d was achieved by preparative HPLC. The four stereoisomers of each natural product were separated by analytical chiral HPLC and their absolute configuration was studied by the combination of HPLC-ECD measurements and TDDFT-ECD calculations. The synthesized flavonoid alkaloids were further characterized by physicochemical and in vitro pharmacological studies.
- Ilkei, Viktor,Spaits, András,Prechl, Anita,Szigetvári, áron,Béni, Zoltán,Dékány, Miklós,Szántay, Csaba,Müller, Judit,K?ncz?l, árpád,Szappanos, ádám,Mándi, Attila,Antus, Sándor,Martins, Ana,Hunyadi, Attila,Balogh, Gy?rgy Tibor,Kalaus, Gy?rgy,B?lcskei, Hedvig,Hazai, László,Kurtán, Tibor
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p. 2523 - 2534
(2016/12/07)
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- A simple synthesis of bannucine and 5′-epibannucine from (-)-vindoline
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Bannucine is an Aspidosperma alkaloid isolated from the dried leaves of Catharanthus roseus. The molecule is a derivative of vindoline bearing a C10 substituent, a pattern common to the antineoplastic dimeric indole alkaloids of C. roseus. In bannucine, a 2-pyrrolidone moiety is attached at C5′ to the aromatic ring of the vindoline core at C10. In the present work we report the synthesis of bannucine and its 5′-epimer from natural (-)-vindoline using a cyclic N-acyliminium ion intermediate whose N-acylaminocarbinol precursor is synthesized by the partial reduction of succinimide. We also describe the separation and the structural analysis of the two epimers, using among others, single crystal X-ray diffraction methods, in order to clarify the orientation of the proton attached to the C5′ carbon. The in vitro antineoplastic activity of the pure epimers was also investigated, but none of the two substances showed significant activity on the examined tumour cell lines.
- Ilkei, Viktor,Bana, Péter,Tóth, Flórián,Palló, Anna,Holczbauer, Tamás,Czugler, Mátyás,Sánta, Zsuzsanna,Dékány, Miklós,Szigetvári, áron,Hazai, László,Szántay, Csaba,Szántay, Csaba,Kalaus, Gy?rgy
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p. 9579 - 9586
(2015/12/01)
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- FUSED TRICYCLIC BENZIMIDAZOLES DERIVATIVES AS MODULATORS OF TNF ACTIVITY
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A series of tricyclic benzimidazole derivatives, in particular dihydro-1H- imidazo [1,2-a]benzimidazo le, dihydro-1H-pyrrolo [1,2-a]benzimidazo le, dihydro-1H- pyrazino[1,2-a]benzimidazole, dihydro-1H-[1,4]oxazino[4,3-a]benzimidazole and dihydrothiazolo[3,4-a]benzimidazolem, and analogues thereof, being potent modulators of human TNFa activity, are accordingly of benefit in the treatment and/or prevention of various human ailments, including autoimmune and inflammatory disorders; neurological and neurodegenerative disorders; pain and nociceptive disorders; cardiovascular disorders; metabolic disorders; ocular disorders; and oncological disorders.
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Page/Page column 121
(2015/06/25)
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- Process for preparing 4-amino-5-hexenoic acid from succinimide
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The present invention relates to a competitive process for the preparation of 4-amino-5-hexenoic acid and intermediates thereof. This compound is a well-known anti-epileptic drug for which several syntheses have been developed, all of them presenting drawbacks. The preparation process according to the present invention is very competitive from an economical point of view and is adapted to industrial scale preparation of 4-amino-5-hexenoic acid.
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Page/Page column 7
(2013/02/28)
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- Cobalt-catalyzed coupling of alkyl iodides with alkenes: Deprotonation of hydridocobalt enables turnover
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Completing the cycle: Cobalt complexes I and II were found to catalyze intramolecular alkyl Heck-type coupling reactions of alkyl iodides to alkenes upon irradiation with visible light in the presence of a tertiary amine base. The use of base is key to the catalytic turnover. The compatibility of the method with a broad range of functional groups opens opportunities for synthesis. Copyright
- Weiss, Matthias E.,Kreis, Lukas M.,Lauber, Alex,Carreira, Erick M.
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supporting information; experimental part
p. 11125 - 11128
(2012/02/02)
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- A synthesis of (±)-stemoamide using the intramolecular propargylic Barbier reaction
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A diastereoselective synthesis of the alkaloid stemoamide has been achieved using the intramolecular propargylic Barbier reaction to construct the seven-membered ring. Georg Thieme Verlag Stuttgart.
- Bates, Roderick W.,Sridhar
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scheme or table
p. 1979 - 1981
(2010/06/17)
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- 2-(2-methylphenyl)-3,4-dihydro-2H-pyrrole derivatives
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The invention relates to novel 2-(2-methylphenyl)-3,4-dihydro-2H-pyrrole derivatives of the formula (I) in whichAr represents substituted phenyl,to a plurality of processes for their preparation and to their use as pesticides.
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- 2-(2-chlorophenyl)-3,4-dihydro-2h-pyrrol derivatives
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The invention relates to novel 2-(2-chlorophenyl)-3,4-dihydro-2H-pyrrole derivatives of the formula (I) in which Ar represents substituted phenyl, to a plurality of processes for their preparation and to their use as pesticides.
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- Cyclic imines as pesticides
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The invention relates to novel cyclic imines of the formula (I) in which Ar1and Ar2each represent substituted phenyl and n represents 1, to a process for their preparation and to their use as pesticides.
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- N-Acyliminium ion chemistry and palladium catalysis: A useful combination to obtain bicyclic heterocycles
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By using N-acyliminium ion chemistry, several ω-propadienyllactams and a propadienyloxazolidine were prepared from N-acyliminium ion precursors and propargylsilanes. Treatment of these allene containing lactams and oxazolidinone with allyl halides or an a
- Karstens, Willem F.J.,Klomp, Dirk,Rutjes, Floris P.J.T.,Hiemstra, Henk
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p. 5123 - 5130
(2007/10/03)
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- Influence of N-substituted lactams on acyclic free radical based hydrogen transfer
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anti Relative stereochemistry is achieved in the hydrogen-transfer reaction of a lactam adjacent to the carbon-centered radical. The sense of diastereoselectivity is reversed using N-substituted lactams, and optimal results favoring syn reduced products are obtained with an α-methylbenzyl group and a Boc group.
- Guindon, Yvan,Bencheqroun, Mohammed
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p. 6041 - 6044
(2007/10/03)
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- Photolysis of olefinic N-chloropyrrolidinones, N-chlorosuccinimides and N-chloro-oxazolidinones: Reactivity of cyclic carboxamidyl, imidyl and carbamyl radicals in intramolecular reactions
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N-Chloro-alkenylpyrrolidinones, an N-chloro-alkenylsuccinimide and N- chloro-alkenyloxazolidinones were prepared as precursors of olefinic cyclic carboxamidyl, imidyl and carbamyl radicals constrained to undergo intramolecular reactions uniquely via their planar or slightly twisted (30- 35°) Π(N) state (1,5-transfer of an allylic hydrogen, 5-exo or 6-exo cyclization to give bicyclo[2.2.1]azaheptane and bicyclo[3.2.1]azaoctane skeletons respectively), those intramolecular reactions being unaccessible to the planar ΣN state. Their photolysis gave products arising uniquely from intermolecular reactions of those nitrogen radicals (addition to an external olefin, hydrogen abstraction from the solvent, allylic hydrogen abstraction). An intramolecular reaction leading to bicyclo[3.3.0]azaoctane derivatives via 5-exo cyclization was observed with an N-chloro-alkenylpyrrolidinone and an N-chloro-alkenyloxazolidinone. In these two cases, both the Π(N) and the Σ(N) states of the cyclic amidyl radical allow orbital overlap for 5-exo cyclization.
- Daoust, Benoit,Lessard, Jean
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p. 3495 - 3514
(2007/10/03)
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- Amnesia-reversal activity of a series of 5-alkoxy-1-arylsulfonyl-2-pyrrolidinones
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A series of 5-alkoxy-1-arylsulfonyl-2-pyrrolidinones were prepared by condensation of arylsulfonyl chlorides with 5-alkoxy-2-pyrrolidinones.Most compounds reversed electroconvulsive shock-induced amnesia in mice, showing the typical inverted U-shaped dose
- Toja, E,Gorini, C,Zirotti, C,Barzaghi, F,Galliani, G
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p. 403 - 413
(2007/10/02)
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