- Synthesis and lateral root-inducing activity of novel N-substituted-2-piperidones with a 1,4-benzodioxan ring
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Novel N-substituted-2-piperidones with a 1,4-benzodioxan ring were prepared and evaluated for their activity to induce lateral roots in lettuce seedlings. Compounds were obtained by aldol condensation of the lithium enolate of N-substituted-2-piperidones
- Tsukada, Hidetaka,Yamada, Naotaka,Taniguchi, Eiji,Kuwano, Eiichi
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Read Online
- η6-Arene CH?O Interaction Directed Dynamic Kinetic Resolution – Asymmetric Transfer Hydrogenation (DKR-ATH) of α-Keto/enol-Lactams
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A dynamic kinetic resolution – asymmetric transfer hydrogenation (DKR-ATH) methodology of α-keto/enol-lactams was developed. We also propose a possible catalytic mechanism evolving a transition state stabilized by η6-arene CH?O interaction. The efficient approach can be applied to a wide range of substrates including non-aryl ones which would be difficult to prepare by other asymmetric reduction methods. (Figure presented.).
- Chen, Yong,Lin, Yicao,Luo, Zhonghua,Sun, Guodong,Wang, Zhongqing,Wu, Shuming,Zhang, Lei
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supporting information
p. 3030 - 3034
(2021/06/01)
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- Synthesis of Lactams by Reductive Amination of Carbonyl Derivatives with ω-Amino Fatty Acids under Hydrosilylation Conditions
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An efficient method for the preparation of lactams from ω-amino fatty acids under hydrosilylation is described. A variety of lactams such as pyrrolidinones, piperidinones and 2-azepanones were selectively synthesised in moderate to excellent yields (29 examples, up to 95 % isolated yields) with a good functional group tolerance. Notably, no metallic based catalyst was required to perform this transformation.
- Tongdee, Satawat,Wei, Duo,Wu, Jiajun,Netkaew, Chakkrit,Darcel, Christophe
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supporting information
p. 5536 - 5539
(2021/08/07)
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- Transition-Metal-Free Reductive Functionalization of Tertiary Carboxamides and Lactams for α-Branched Amine Synthesis
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A new method for the synthesis of α-branched amines by reductive functionalization of tertiary carboxamides and lactams is described. The process relies on the efficient and controlled reduction of tertiary amides by a sodium hydride/sodium iodide composite, in situ treatment of the resulting anionic hemiaminal with trimethylsilyl chloride and subsequent coupling with nucleophilic reagents including Grignard reagents and tetrabutylammonium cyanide. The new method exhibits broad functional-group compatibility, operates under transition-metal-free reaction conditions, and is suitable for various synthetic applications on both sub-millimole and on multigram scales.
- Chiba, Shunsuke,Dixon, Darren J.,Fan, Dongyang,Ong, Derek Yiren
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supporting information
p. 11903 - 11907
(2020/05/22)
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- Solvent-free iron(III) chloride-catalyzed direct amidation of esters
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Amide functional groups are prominent in a broad range of organic compounds with diverse beneficial applications. In this work, we report the synthesis of these functional groups via an iron(iii) chloride-catalyzed direct amidation of esters. The reactions are conducted under solvent-free conditions and found to be compatible with a range of amine and ester substrates generating the desired amides in short reaction times and good to excellent yields at a catalyst loading of 15 mol%.
- Mkhonazi, Blessing D.,Shandu, Malibongwe,Tshinavhe, Ronewa,Simelane, Sandile B.,Moshapo, Paseka T.
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supporting information
(2020/03/17)
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- A Unified Strategy for the Synthesis of Difluoromethyl- And Vinylfluoride-Containing Scaffolds
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Here, we report a general method for the synthesis of quaternary and tertiary difluoromethylated compounds and their vinylfluoride analogues. The strategy, which relies on a two-step sequence featuring a C-selective electrophilic difluoromethylation and either a palladium-catalyzed decarboxylative protonation or a Krapcho decarboxylation, is practical, scalable, and high yielding. Considering the generality of the method and the attractive properties offered by the difluoromethyl group, this approach provides a valuable tool for late-stage functionalization and drug development.
- Duchemin, Nicolas,Buccafusca, Roberto,Daumas, Marc,Ferey, Vincent,Arseniyadis, Stellios
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supporting information
p. 8205 - 8210
(2019/10/16)
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- Iron-Catalysed Reductive Amination of Carbonyl Derivatives with Ω-Amino Fatty Acids to Access Cyclic Amines
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An efficient method for the reductive amination of carbonyl derivatives with ω-amino fatty acids catalysed by an iron complex Fe(CO)4(IMes) [IMes=1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene] by means of hydrosilylation was developed. A variety of pyrrolidines, piperidines and azepanes were selectively synthesised in moderate-to-excellent yields (36 examples, 47–97 % isolated yield) with a good functional group tolerance.
- Wei, Duo,Netkaew, Chakkrit,Carré, Victor,Darcel, Christophe
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p. 3008 - 3012
(2019/05/15)
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- Palladium-Catalyzed Hydrocarbonylative C-N Coupling of Alkenes with Amides
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An efficient palladium-catalyzed hydrocarbonylative C-N coupling of alkenes with amides has been developed. The reaction was performed via hydrocarbonylation of alkenes, followed by acyl metathesis with amides. Both intermolecular and intramolecular react
- Zhou, Xibing,Zhang, Guoying,Gao, Bao,Huang, Hanmin
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supporting information
p. 2208 - 2212
(2018/04/30)
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- C(sp3)-H dehydrogenation and C(sp2)-H alkoxy carbonylation of inactivated cyclic amines towards functionalized N-heterocycles
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A novel and efficient synthesis of tetrahydropyridine (THP)-, dihydropyrrole (DHP)-, or tetrahydroazepine (THA)-3-carboxylates via cascade reactions of inactivated cyclic amines with CO and alcohols is presented. To our knowledge, this should be the first
- He, Yan,Wang, Fang,Zhang, Xinying,Fan, Xuesen
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supporting information
p. 4002 - 4005
(2017/04/11)
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- Transition-Metal-Free Amine Oxidation: A Chemoselective Strategy for the Late-Stage Formation of Lactams
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A metal-free strategy for the formation of lactams via selective oxidation of cyclic secondary and tertiary amines is described. Molecular iodine facilitates both chemoselective and regioselective oxidation of C-H bonds directly adjacent to a cyclic amine. The mild conditions, functional group tolerance, and substrate scope are demonstrated using a suite of diverse small molecule cyclic amines, including clinically approved drug scaffolds.
- Griffiths, Robert J.,Burley, Glenn A.,Talbot, Eric P. A.
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supporting information
p. 870 - 873
(2017/02/26)
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- Preparation of conformationally restricted β2,2- and β2,2,3-amino esters and derivatives containing an all-carbon quaternary center
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β-Amino acids are routinely incorporated into peptidic drugs to increase their stability and to incur conformational biases. However, the synthesis of highly substituted β-amino acids still represents a great challenge. A new approach to their preparation is reported involving a Vilsmeier-Haack reaction with nonaromatic carbon nucleophiles. The highly challenging preparation of contiguous tertiary and all-carbon quaternary centers was successfully used to generate several β2,2,3-amino esters, such as derivatives of homoproline, homoalanine, and homopipecolinic esters.
- Romanens, Alexandre,Blanger, Guillaume
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supporting information
p. 322 - 325
(2015/01/30)
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- Palladium(II)-Catalyzed Allylic C H Oxidation of Hindered Substrates Featuring Tunable Selectivity Over Extent of Oxidation
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The use of Oxone and a palladium(II) catalyst enables the efficient allylic C H oxidation of sterically hindered α-quaternary lactams which are unreactive under known conditions for similar transformations. This simple, safe, and effective system for C H activation allows for unusual tunable selectivity between a two-electron oxidation to the allylic acetates and a four-electron oxidation to the corresponding enals, with the dominant product depending on the presence or absence of water. The versatile synthetic utility of both the allylic acetate and enal products accessible through this methodology is also demonstrated.
- Xing, Xiangyou,O'Connor, Nicholas R.,Stoltz, Brian M.
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supporting information
p. 11186 - 11190
(2016/07/06)
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- Iron(II) pincer-catalyzed synthesis of lactones and lactams through a versatile dehydrogenative domino sequence
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The synthesis of lactones and lactams by using iron(II) pincer-catalyzed dehydrogenative methodology was developed. Starting from 1,n-diols or 1,n-amino alcohols, this domino transformation takes place through initial dehydrogenation of the substrates, subsequent intramolecular cyclization, and final oxidation to afford the desired products in good yields. The ability to access heterocycles of different sizes makes this protocol especially versatile, in which two consecutive oxidation reactions are performed without requiring an external oxidant. In this paper, we report the application of the Fe-MACHO-BH complex [carbonylhydrido(tetrahydroborato)[bis(2-diisopropylphosphinoethyl)amino]iron(II)] in this atom-efficient and environmentally benign process, for which molecular hydrogen is formed as the only stoichiometric side product. Just a little pinch: The iron(II) pincer-catalyzed synthesis of lactones and lactams from easily available 1,n-diols and 1,n-amino alcohols is explored. The use of a nontoxic metal as well as the generation of molecular hydrogen as the only stoichiometric byproduct makes this method a highly atom-efficient and environmentally benign process.
- Pea-Lpez, Miguel,Neumann, Helfried,Beller, Matthias
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p. 865 - 871
(2015/03/14)
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- Iridium-Catalyzed Single-Step N-Substituted Lactam Synthesis from Lactones and Amines
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Catalytic lactam synthesis was achieved directly from lactones and amines using an Ir catalyst. Three sequential transformations - aminolysis of lactone, N-alkylation of amine with hydroxyamide, and intramolecular transamidation of aminoamide - afforded the corresponding N-substituted lactams. (Figure Presented).
- Kim, Kicheol,Hong, Soon Hyeok
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p. 4152 - 4156
(2015/05/04)
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- Synthesis, spectral, and anti-microbial studies of thioiminium iodides and amine hydrochlorides
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To avoid the undesired deprotonation during the addition of organolithium and organomagnesium reagents to ketones, the thioiminium salts, easily prepared from lactams and amides are converted into 2,2-disubstituted and 2-monosubstituted amines by reaction with simple nucleophiles such as organocerium and organocopper reagents. The reaction of thioiminium iodides with organocerium reagents derived by transmetalation of corresponding lithium reagents with anhydrous cerium(III) chloride has been investigated. These thioiminium iodides act as good electrophiles and accept alkylceriums towards bisaddition. The newly synthesized amines have been characterized by 1H and 13C NMR, IR and mass spectra. The amines have been converted into their hydrochlorides and characterized by COSY. These hydrochlorides have been subjected to antimicrobial screening with clinically isolated microorganisms, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi and Candida albicans. The hydrochlorides show quite good activity against these bacteria and fungus.
- Britto, Sebastian,Renaud, Philippe,Nallu, Maruthai
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supporting information
p. 489 - 493
(2013/12/04)
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- Asymmetric synthesis and evaluation of α-quaternary chiral lactam derivatives as novel anticancer agents
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Asymmetric synthesis of α-quaternary chiral lactam derivatives as novel anticancer agents and evaluation of their cytotoxic potentials and spectrums are reported. Among the developed lactam derivatives, the most active new compounds (S)-4m and (S)-4n synthesized via asymmetric phase-transfer catalytic alkylation in very high optical yields (98 % ee) show promising in vitro anticancer activities with low micromolar IC50 values against colon, uterus, lung, and breast human cancer cells.
- Lee, Hwanhyuk,Hwang, Su Jung,Jung, Jisung,Hong, Suckchang,Lee, Myungmo,Park, Hyeung-Geun,Lee, Hyo-Jong,Park, Yohan
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p. 1264 - 1270
(2015/10/05)
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- Catalytic asymmetric allylic alkylation of 3-arylated piperidin-2-ones
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The preparation of optically active lactams from 3-aryl-2-piperidinone is reported. The quaternary carbon stereocentres were formed using palladium-catalysed asymmetric allylic alkylation reactions. The resulting enantioenriched compounds are useful inter
- Michon, Christophe,Bethegnies, Aurelien,Capet, Frederic,Roussel, Pascal,De Filippis, Arnault,Gomez-Pardo, Domingo,Cossy, Janine,Agbossou-Niedercorn, Francine
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p. 4979 - 4985
(2013/08/23)
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- Besting vitamin E: Sidechain substitution is key to the reactivity of naphthyridinol antioxidants in lipid bilayers
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A series of naphthyridinol analogs of α-tocopherol (α-TOH, right) with varying sidechain substitution was synthesized to determine how systematic changes in the lipophilicity of these potent antioxidants impact their radical-trapping activities in lipid b
- Li, Bo,Harjani, Jitendra R.,Cormier, Nicholas S.,Madarati, Hasam,Atkinson, Jeffrey,Cosa, Gonzalo,Pratt, Derek A.
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supporting information
p. 1394 - 1405
(2013/03/14)
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- A one-pot selective synthesis of N-Boc protected secondary amines: Tandem direct reductive amination/N-Boc protection
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A one-pot tandem direct reductive amination of aldehydes with primary amines resulting in N-Boc secondary amines using a (Boc)2O/sodium triacetoxyborohydride (STAB) system is reported. The tandem procedure is efficient, selective, and versatile, giving excellent yields of N-Boc protected secondary amines even in those cases where the products are prone to intramolecular lactamization.
- Neelarapu, Raghupathi,Petukhov, Pavel A.
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scheme or table
p. 7056 - 7062
(2012/08/28)
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- Scope and applications of second generation palladium-catalyzed cycloalkenylation. Stereoselective total syntheses of isoiridomyrmecin, isodihydronepetalactone, and α-skytanthine
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Functionalized bicyclo[3.2.1]octanes, -oxabicyclo-[4.3.0]nonanes, 3-azabicyclo[3.3.0]octanes, and 3-azabicyclo[4.3.0]nonanes were easily synthesized via a second generation palladium-catalyzed cycloalkenylation. Isoiridomyrmecin and isodihydronepetalactone, both of which feature a 3-oxabicyclo[4.3.0]nonane subunit, were stereoselectively synthesized via a second generation palladium-catalyzed cycloalkenylation as the key step. α-Skytanthine, a typical 3-azabicyclo[4.3.0]nonane alkaloid, was also constructed using the same catalytic cyclization protocol.
- Takeda, Kazutaka,Toyota, Masahiro
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experimental part
p. 9909 - 9921
(2012/02/06)
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- NHC-Catalyzed intramolecular redox amidation for the synthesis of functionalized lactams
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A very efficient NHC-catalyzed lactamization reaction is reported. For most cases, the ring expansion reaction proceeds to cleanly furnish five- and six-membered N-Ts and N-Bn lactams, without the need for further purification. Evidence is presented suggesting a dual role for the stoichiometric base: (1) deprotonation of the triazolium precatalyst and (2) activation of the nitrogen leaving group through hydrogen bonding.
- Thai, Karen,Wang, Li,Dudding, Travis,Bilodeau, Francois,Gravel, Michel
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supporting information; experimental part
p. 5708 - 5711
(2011/03/19)
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- An experimental-theoretical study of the factors that affect the switch between ruthenium-catalyzed dehydrogenative amide formation versus amine alkylation
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A ruthenium(II) diamine complex can catalyze the intramolecular cyclization of amino alcohols H2N(CH2)nOH via two pathways: (i) one yields the cyclic secondary amine by a redox-neutral hydrogen-borrowing route with loss of water; and (ii) the second gives the corresponding cyclic amide by a net oxidation involving loss of H2. The reaction is most efficient in cases where the product has a six-membered ring. The amide and amine pathways are closely related: DFT calculations show that both amine and amide formations start with the oxidation of the amino alcohol, 5-amino-1-pentanol, to the corresponding amino aldehyde, accompanied by reduction of the catalyst. The intramolecular condensation of the amino aldehyde takes place either in the coordination sphere of the metal (path I) or after dissociation from the metal (path II). Path I yields the Ru-bound zwitterionic form of the hemiaminal protonated at nitrogen, which eliminates H2, forming the amide product. In path II, the free hemiaminal dehydrates, giving an imine, which yields the amine product by hydrogenation with the reduced form of the catalyst generated in the initial amino alcohol oxidation. For amide to be formed, the hemiaminal must remain metal-bound in the key intermediate and the elimination of H2 must occur from the same intermediate to provide a vacant site for β-elimination. The elimination of H2 is affected by an intramolecular H-bond in the key intermediate. For amine to be formed, the hemiaminal must be liberated for dehydration to imine and the H2 must be retained on the metal for reduction of the imine intermediate.
- Nova, Ainara,Balcells, David,Schley, Nathan D.,Dobereiner, Graham E.,Crabtree, Robert H.,Eisenstein, Odile
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experimental part
p. 6548 - 6558
(2011/02/17)
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- A samarium(II)-mediated, stereoselective cyclization for the synthesis of azaspirocycles
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(Chemical Equation Presented) Unsaturated keto-lactams undergo sequential conjugate reduction-aldol cyclization on treatment with SmI2 to give syn-spirocyclic pyrrolidinones and piperidinones containing vicinal, fully substituted stereocenters with complete diastereocontrol. The substituent on nitrogen and the lactam ring size have a marked impact on the efficiency of the spirocyclization.
- Guazzelli, Giuditta,Duffy, Lorna A.,Procter, David J.
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supporting information; experimental part
p. 4291 - 4294
(2009/06/06)
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- Fast, acid-free, and selective lactamization of lactones in ionic liquids
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(Chemical Equation Presented) A fast and acid-free one-pot 0.2-30 mmol microwave methodology for direct ionic liquid-mediated preparation of lactams from lactones and primary amines has been developed. The protocol was investigated with a wide range of primary amines and a handful of lactones, including substrates with acid-sensitive substituents. Both γ-lactams and δ-lactams were, despite the complete absence of a Bronsted acid, obtained in useful to excellent yields after only 35 min of microwave processing.
- Orrling, Kristina M.,Wu, Xiongyu,Russo, Francesco,Larhed, Mats
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supporting information; experimental part
p. 8627 - 8630
(2009/04/11)
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- Di-μ-hydroxy-bis(N,N,N′,N′-tetramethylenediamine)-copper(II) chloride [Cu(OH)·TMEDA]2Cl2: An efficient, practical catalyst for benzylation and allylation of amides
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An efficient protocol for the benzylation or allylation of amides using the corresponding benzyl or allyl chlorides as electrophiles under basic conditions with commercially available 5 mol % of [Cu(OH)TMEDA]2Cl2 as catalyst was developed. Under these conditions, unprotected amino acids were benzylated without any racemization.
- Kumaraswamy,Pitchaiah,Ramakrishna,Ramakrishna,Sadaiah
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p. 2013 - 2015
(2007/10/03)
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- Synthesis of functionalised azecine and azonine derivatives via an enolate assisted aza Claisen rearrangement
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This paper describes the synthesis of functionalised azecine and azonine derivatives incorporating the adrenaline motif. In a key step, an enolate assisted aza Claisen rearrangement was employed to interconvert from 6- and 5-membered heterocycles to their corresponding 10- and 9-membered lactams.
- Bremner, John B.,Perkins, David F.
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p. 2659 - 2665
(2007/10/03)
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- Simple preparation of 3-Aryl 2-piperidinones
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A very simple method for obtaining α-arylated N-protected 2-piperidinones in high yields is described. The use of ZnCl2, LiHMDS or s-BuLi as the base and Pd(dba)2 as the catalyst are the key factors.
- De Filippis, Arnault,Pardo, Domingo Gomez,Cossy, Janine
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p. 2930 - 2933
(2007/10/03)
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- Palladium-catalyzed α-arylation of N-protected 2-piperidinones
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A very simple method for obtaining α-arylated N-protected 2-piperidinones in high yield is described. The use of ZnCl2 and Pd(dba)2 and the nature of the base are the key factors.
- Filippis, Arnault de,Pardo, Domingo Gomez,Cossy, Janine
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p. 9756 - 9768
(2007/10/03)
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- Palladium-catalyzed intermolecular α-arylation of N-protected 2-piperidinones
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(Matrix presented) The α-arylation of the zinc enolate of N-protected 2-piperidinones with aryl bromides in the presence of a palladium catalyst is described as a general method.
- Cossy, Janine,de Filippis, Arnault,Gomez Pardo, Domingo
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p. 3037 - 3039
(2007/10/03)
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- USE OF POLYPEPTIDE
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The present invention provides uses of a polypeptide having a ligand activity to a sensory epithelium neuropeptide-like receptor (SENR) which is a G protein-coupled receptor protein, and a DNA encoding the same. More specifically, the present invention provides an anti-attention-deficit-disorder or anti-narcolepsy agent, which comprises a polypeptide having a ligand activity for SENR or a salt thereof, as well as a method for screening compounds having an anti-attention-deficit-disorder or anti-narcolepsy activity or compounds having an anti-anxiety, anti-depression, anti-insomnia, anti-schizophrenia or anti-fear activity or salts thereof, which comprises using the above polypeptide or a precursor protein of the polypeptide or a salt thereof.
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- Vasoactive agents
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A vasoactive drug is provided which comprises a compound having GPR14-antagonizing activity or salts thereof.
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- Substituted piperidines useful for the treatment of allergic diseases
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The present invention relates to novel substituted piperidine derivatives of the formula STR1stereoisomers thereof, and pharmaceutically acceptable salts thereof which are useful as histamine receptor antagonists and tachykinin receptor antagonist. Such antagonists are useful in the treatment of allergic diseases including: seasonal rhinitis, allergic rhinitis, and sinusitis.
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- Pyrrolidinones derived from (S)-pyroglutamic acid. Part 2. Conformationally constrained kainoid analogues
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Derivation of pyrrolidinones from (S)-pyroglutamic acid was described. The procedure permitted the sequential modification of C-3 and C-4 substituents of the kainoids. This allowed access to a diverse range of compounds. The pyrrolidinone ring conformation appeared to be controllable by the nature of remote substituents on the heterocyclic ring.
- Dyer, James,King, Amanda,Keeling, Steve,Moloney, Mark G.
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p. 2793 - 2804
(2007/10/03)
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- Reaction of β-, γ-, and δ-chloroalkanamides with potassium tert-butoxide in tetrahydrofuran: Elimination, and lactamization
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γ- and δ-Chloroalkanamides were found to undergo lactamization readily when treated with potassium tert-butoxide in tetrahydrofuran. Raising the reaction temperature may encourage SN2 displacement reaction. On the other hand β-chloroalkanamides only undergo elimination, followed by dimerization and trimerization of the acrylamide initially formed.
- Wang, Eng Chi,Lin, Huey-Jen
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p. 481 - 489
(2007/10/03)
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- Preparation and epoxidation of conjugated lactams: Influence of ring size on epoxidation
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α,β-Epoxy-lactams can be prepared from conjugated lactams by treatment with m-chloroperoxybenzoic acid. Good yields are obtained, however, only with 2-pyrrolidinone derivatives. The yield of epoxy-lactam diminishes dramatically as the size of the lactam ring increases.
- Li,Smith
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p. 1265 - 1275
(2007/10/02)
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- Synthetic Applications of 2-(1,3-Dithian-2-yl)indoles. IV. New Synthesis of the Tetracyclic ABED Ring System of Strychnos Alkaloids
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A new and versatile synthesis of tetracyclic compounds 10, 22 and 24 presenting the ABED ring system of Strychnos alkaloids is described by closure of the C1-C11b bond in the key step.The intermediate tetrahydropyridinium salts 2 have been obtained from 2-(1,3-dithian-2-yl)indole (3) and either 2-cyano-3-ethyl-1-methyl-1,2,3,6-tetrahydropyridine (4a) or N-substituted Δ3-piperidein-2-ones (5).
- Diez, Anna,Castells, Josep,Forns, Pilar,Rubiralta, Mario,Grierson, David S.,et al.
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p. 6585 - 6602
(2007/10/02)
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- EFFICIENT MICHAEL ADDITION REACTIONS OF THE N-ARYLSULFONYL-3-PHENYLTHIOPIPERIDONES. SYNTHESIS OF 3-SUBSTITUTED DIHYDROPYRIDINONES
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Efficient methods for the Michael addition reactions of N-arylsulfonyl-3-phenylthiopiperidones (1) with both the protected amidoacrylates (4, 9) and the simple acrylates (12) have been developed.These reactions offer an efficient route to the 3-alkyl-substituted dihydropyridinones (3, 11), the dienophiles employed in the natural product synthesis.
- Nakagawa, Masako,Torisawa, Yasuhiro,Hosaka, Toshihiro,Tanabe, Kiyoshi,Tavet, Fabrice,et al.
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p. 1157 - 1170
(2007/10/02)
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- A REGIOSELECTIVE DIELS-ALDER SYNTHESIS OF ELLIPTICINE
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The trimethylsilyl trifluoromethanesulfonate accelerated Diels-Alder reaction between 1,3-dimethyl-4-(phenylsulfonyl)-4H-furoindole (3) and 5,6-dihydropyridones (10) shows high regioselectivity, yielding carbazole 11 upon hydrolytic workup.Carbazole 11b has been successfully converted to the pyridocarbazole alkaloid ellipticine (1).
- Davis, Deborah A.,Gribble, Gordon W.
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p. 1081 - 1084
(2007/10/02)
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- Cyclic Allylamine-Enamine Systems. Part 8. Isomerisation Using Rhodium Complexes. 3-Aminoalkylidene-3H-indoles. Part 5. 6,7-Dihydroindoloquinolizine and 1,2,3,4,6,7-Hexahydroindoloquinolizine
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The use of rhodium-complex catalysis for cyclic allylamine --> cyclic enamine isomerisation is described.Indoloquinolizines are produced using this methodology and also via 3-amino-3H-indole intermediates.N-alkylation of N-silylated amides is described.
- Salas, Marisa,Al-Khawaja, Ibtisam K.,Thomas, Michelle J.,Joule, John A.
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p. 1666 - 1675
(2007/10/02)
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- An Efficient Synthesis of Acetylated Bicyclic Hydroxypyrroles from Cyclic Lactams via Flash-Vacuum Pyrolysis of Meldrum's Acid Derivatives
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The title compounds 9 were synthesized in three steps from cyclic lactams 2.After treatment of 2a-h with phosgene followed by the addition of Meldrum's acid to the chloroiminium chloride intermediates 3a-h, derivatives 4a-h were isolated in good yields.Compounds 4a-g were quantitatively converted to bicyclic enaminones 7a-g by flash-vacuum pyrolysis in the temperature range 480-600 deg C.In contrast, 4h provided 8h, the hydroxyprrole tautomer of 7h.The reaction takes place through the initial formation of (aminomethylene)ketenes 5a-h followed by a 1,4-hydrogen migration from the carbon adjacent to the nitrogen atom to the central carbon of the cumulenone.The lower temperature (480 deg C) needed for benzyl and N-carboalkoxy derivatives 4e-h in comparison with N-alkyl derivatives 4a-d (600 deg C) is correlated with gas-phase acidity of the migrating hydrogen atom.The hydroxypyrroles 8a-g, tautomers of 7a-g (78), were trapped with acetic anhydride, affording O-acetylated bicyclic hydroxypyrroles 9a-g.
- Pommelet, Jean-Claude,Dhimane, Hamid,Chuche, Josselin,Celerier, Jean-Pierre,Haddad, Mansour,Lhommet, Gerard
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p. 5680 - 5685
(2007/10/02)
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