- Pd(II)-catalyzed intramolecular oxidative Heck dearomative reaction: Approach to thiazole-fused pyrrolidinones with a C2-azaquarternary center
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A Pd(ii)-catalyzed intramolecular oxidative Heck dearomative reaction for the construction of thiazole-fused pyrrolidinones with a C2-azaquarternary center and C3-exo-double bond has been achieved for the first time. The reaction exhibited good functional group tolerance and gram-scale capacity.
- Gao, Shang,Yang, Chi,Huang, Yue,Zhao, Lei,Wu, Xiaoming,Yao, Hequan,Lin, Aijun
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Read Online
- Synthesis and evaluation of aryl substituted propyl piperazines for potential atypical antipsychotic activity
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Background: Schizophrenia is a disorder with complex etiology with hyperdopaminer-gia as the leading underlying cause. Atypical antipsychotics are the agents which do not give rise to significant extrapyramidal side effects and are more effective against negative symptoms of schizophrenia. Introduction: A new series of chloro-substituted substituted aryloxypiperazine derivatives and their indole based derivatives was designed and evaluated for atypical antipsychotic activity based on established models for combined dopaminergic and serotonergic antagonism. Method: The present series of compounds were designed based on 3D similarity studies, synthesized and evaluated for atypical antipsychotic activity in animal models for combined dopaminer-gic and serotonergic antagonism. The blood-brain barrier penetration potential was assessed from theoretical log BB values computed through an online software program. Results: Theoretical ADME profiling of the designed compounds based on selected physicochem-ical parameters suggested excellent compliance with Lipinski’s rules. The log BB values obtained for the compounds suggested a good potential for brain permeation. Indole substitution contributed towards an improved efficacy over aryloxy analogs. Lead compounds showed a potential for combined dopaminergic and serotonergic antagonism. Conclusion: The 5-methoxy indole based compounds 16 and 17 were identified as the lead compounds displaying a potential atypical antipsychotic profile.
- Singh, Shalu,Bali, Alka,Peshin, Tania
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p. 429 - 441
(2021/03/26)
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- One-pot, three-component Fischer indolisation-N-alkylation for rapid synthesis of 1,2,3-trisubstituted indoles
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A one-pot, three-component protocol for the synthesis of 1,2,3-trisubstituted indoles has been developed, based upon a Fischer indolisation-indoleN-alkylation sequence. This procedure is very rapid (total reaction time under 30 minutes), operationally straightforward, generally high yielding and draws upon readily available building blocks (aryl hydrazines, ketones, alkyl halides) to generate densely substituted indole products. We have demonstrated the utility of this process in the synthesis of 23 indoles, benzoindoles and tetrahydrocarbazoles bearing varied and useful functionality.
- Hughes-Whiffing, Christopher A.,Perry, Alexis
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supporting information
p. 627 - 634
(2021/02/06)
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- Acceptorless dehydrogenative condensation: synthesis of indoles and quinolines from diols and anilines
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The use of diols and anilines as reagents for the preparation of indoles represents a challenge in organic synthesis. By means of acceptorless dehydrogenative condensation, heterocycles, such as indoles, can be obtained. Herein we present an experimental and theoretical study for this purpose employing heterogeneous catalysts Pt/Al2O3and ZnO in combination with an acid catalyst (p-TSA) and NMP as solvent. Under our optimized conditions, the diol excess has been reduced down to 2 equivalents. This represents a major advance, and allows the use of other diols. 2,3-Butanediol or 1,2-cyclohexanediol has been employed affording 2,3-dimethyl indoles and tetrahydrocarbazoles. In addition, 1,3-propanediol has been employed to prepare quinolines or natural and synthetic julolidines.
- Bellezza, Delia,Zaragozá, Ramón J.,José Aurell,Ballesteros, Rafael,Ballesteros-Garrido, Rafael
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supporting information
p. 677 - 683
(2021/02/06)
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- Synthesis of indoles through acceptorless dehydrogenative coupling catalyzed by nickel on silica-alumina
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The high atom-economical formation of indoles from anilines and diols was described with affordable and easy to handle Ni/SiO2-Al2O3. After optimization, 2,3-dimethylindole was isolated with an excellent 98% yield in neat conditions. The scope of the reaction was studied and 13 indoles were isolated in 16–80% yields.
- Charvieux, Aubin,Hammoud, Abdul Aziz,Duclos, Marie-Christine,Duguet, Nicolas,Métay, Estelle
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supporting information
(2021/07/25)
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- Fe-Catalyzed Sequential C(sp3)-H/N-H Annulation of 2-Methylindoles with Ethyl Trifluoropyruvate at Room Temperature: Construction of Pyrrolo[1,2-α]indoles
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An efficient and benign iron-catalyzed room-temperature method was developed for direct sequential C(sp3)-H/N-H annulation to construct pyrroloindole scaffolds. This strategy features cheap and readily available raw materials and mild room-temperature reaction conditions and provides a green and practical method for the one-pot rapid synthesis of a wide range of diversely functionalized pyrrolo[1,2-α]indoles.
- Wang, Le,Wang, Le,Zhou, Jia,Chen, Han-Qia,Li, Dong-Li,Lin, Jun-Bing,Lin, Jun-Bing,Li, Ke,Ding, Tong-Mei,Zhang, Shu-Yu,Zhang, Shu-Yu
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supporting information
p. 4716 - 4720
(2020/06/29)
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- Allylic and Allenylic Dearomatization of Indoles Promoted by Graphene Oxide by Covalent Grafting Activation Mode
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The site-selective allylative and allenylative dearomatization of indoles with alcohols was performed under carbocatalytic regime in the presence of graphene oxide (GO, 10 wt percent loading) as the promoter. Metal-free conditions, absence of stoichiometric additive, environmentally friendly conditions (H2O/CH3CN, 55 °C, 6 h), broad substrate scope (33 examples, yield up to 92 percent) and excellent site- and stereoselectivity characterize the present methodology. Moreover, a covalent activation model exerted by GO functionalities was corroborated by spectroscopic, experimental and computational evidences. Recovering and regeneration of the GO catalyst through simple acidic treatment was also documented.
- Lombardi, Lorenzo,Bellini, Daniele,Bottoni, Andrea,Calvaresi, Matteo,Monari, Magda,Kovtun, Alessandro,Palermo, Vincenzo,Melucci, Manuela,Bandini, Marco
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p. 10427 - 10432
(2020/07/24)
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- B(C6F5)3-Catalyzed Direct C3 Alkylation of Indoles and Oxindoles
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The direct C3 alkylation of indoles and oxindoles is a challenging transformation, and only a few direct methods exist. Utilizing the underexplored ability of triaryl boranes to mediate the heterolytic cleavage of α-nitrogen C-H bonds in amines, we have developed a catalytic approach for the direct C3 alkylation of a wide range of indoles and oxindoles using amine-based alkylating agents. We also employed this borane-catalyzed strategy in an alkylation-ring opening cascade.
- Basak, Shyam,Alvarez-Montoya, Ana,Winfrey, Laura,Melen, Rebecca L.,Morrill, Louis C.,Pulis, Alexander P.
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p. 4835 - 4840
(2020/04/22)
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- Palladium-Catalyzed Amination/Dearomatization Reaction of Indoles and Benzofurans
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This report describes a palladium-catalyzed dearomatization and amination tandem reaction of 2,3-disubstituted indoles and benzofurans via the Catellani strategy. This reaction provides a new method for the construction of amino-substituted indoline-fused cyclic and benzofuran spiro compounds in good yields. The reaction has broad functional group compatibility and substrate scope.
- Zhang, Zhe,Zhang, Bo-Sheng,Li, Kai-Li,An, Yang,Liu, Ce,Gou, Xue-Ya,Liang, Yong-Min
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p. 7817 - 7839
(2020/07/16)
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- Asymmetric N-Hydroxyalkylation of Indoles with Ethyl Glyoxalates Catalyzed by a Chiral Phosphoric Acid: Highly Enantioselective Synthesis of Chiral N,O-Aminal Indole Derivatives
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A method of SPINOL-derived chiral phosphoric acid catalyzed asymmetric intermolecular N-hydroxyalkylation of multisubstituted indoles with ethyl glyoxalates is described in this report. This protocol provides an alternative, convenient, and direct strategy for efficient access to structurally unique α-chiral indole N,O-acyclic aminals with a broad substrate scope and good to excellent enantioselectivities. The synthetic utility of this methodology is illustrated by a gram-scale experiment and the subsequent efficient synthesis of more complex chiral N,O-aminal indole derivatives.
- Wang, Le,Zhou, Jia,Ding, Tong-Mei,Yan, Zhi-Qiang,Hou, Si-Hua,Zhu, Guo-Dong,Zhang, Shu-Yu
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supporting information
p. 2795 - 2799
(2019/04/30)
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- Dearomatization of Indoles via Palladium-Catalyzed Allylic C-H Activation
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The first Pd-catalyzed allylic dearomatization of substituted indoles triggered by C-H bond activation is reported. The presence of a catalytic amount of 2,5-DMBQ is proven to be a key factor for the high yield. This one-pot tandem allylic C-H activation/dearomatization sequence provides a straightforward access to 3,3-disubstituted indolines.
- Zhang, Heng,Hu, Rong-Bin,Liu, Na,Li, Shi-Xia,Yang, Shang-Dong
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supporting information
p. 28 - 31
(2016/01/15)
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- FUNCTIONALISED AND SUBSTITUTED INDOLES AS ANTI-CANCER AGENTS
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The present invention relates broadly to functionalised and substituted indoles, the preparation thereof and their use in the treatment of proliferative diseases such as cancer.
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Page/Page column 122
(2016/12/22)
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- FUNCTIONALISED AND SUBSTITUTED INDOLES AS ANTI-CANCER AGENTS
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The present invention relates to anti-tropomyosin compounds, processes for their preparation, and methods for treating or preventing a disease or disorder, such as a proliferative disease (preferably cancer), using compounds of the invention.
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Page/Page column 36
(2016/02/05)
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- Palladium-Catalyzed Dearomative Allylic Alkylation of Indoles with Alkynes to Synthesize Indolenines with C3-Quarternary Centers
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A palladium-catalyzed dearomative allylic alkylation of indoles with alkynes to construct indolenines with C3-quarternary centers was reported. The in situ formed arylallene intermediate omitted the need to install leaving groups on the allylic compounds and employ extra oxidants to oxidize the allylic C-H bonds. The reaction exhibited good functional group tolerance and high atom economy. Moreover, the reaction was further expanded to synthesize pyrroloindolines and furanoindolines.
- Gao, Shang,Wu, Zijun,Fang, Xinxin,Lin, Aijun,Yao, Hequan
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supporting information
p. 3906 - 3909
(2016/08/16)
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- Catalytic methylation of C-H bonds using CO2 and H2
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Formation of C-C bonds from CO2 is a much sought after reaction in organic synthesis. To date, other than C-H carboxylations using stoichiometric amounts of metals, base, or organometallic reagents, little is known about C-C bond formation. In fact, to the best of our knowledge no catalytic methylation of C-H bonds using CO2 and H2 has been reported. Described herein is the combination of CO2 and H2 for efficient methylation of carbon nucleophiles such as indoles, pyrroles, and electron-rich arenes. Comparison experiments which employ paraformaldehyde show similar reactivity for the CO2/H2 system. Capturing: Carbon dioxide in the presence of H2 is shown to be an efficient methylating reagent for carbon nucleophiles such as 2-substituted indoles, pyrroles, and electron-rich arenes. Experimental data support the formal capture of formaldehyde. acac=acetylacetonate, triphos=1,1,1-tris(diphenylphosphinomethyl)ethane.
- Li, Yuehui,Yan, Tao,Junge, Kathrin,Beller, Matthias
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supporting information
p. 10476 - 10480
(2016/02/18)
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- Facile construction of pyrrolophenanthridone skeleton via a one-pot intramolecular Heck reaction and oxidation
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Construction of pyrrolophenanthridone skeleton via a one-pot Pd-catalyzed intramolecular Heck reaction followed by oxidation has been achieved in moderate to good yields. The reaction mechanism has been proposed.
- Cong, Wei,Zhao, Lei,Wu, Xiaoming,Xu, Jinyi,Yao, Hequan
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supporting information
p. 312 - 317
(2014/01/06)
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- A variation of the Fischer indolization involving condensation of quinone monoketals and aliphatic hydrazines
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A new twist: A one-pot nitrous acid free, diazonium-free, and transition-metal-free variation of the Fischer indole synthesis has been developed. Condensation of quinone monoketals and aliphatic hydrazine hydrochlorides afforded indoles via intermediate alkylaryldiazenes. This method will complement the classical Fischer indole synthesis by providing indoles in two steps from widely available phenols under mild conditions. Copyright
- Zhang, Jinzhu,Yin, Zhiwei,Leonard, Patrick,Wu, Jing,Sioson, Kate,Liu, Che,Lapo, Robert,Zheng, Shengping
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supporting information
p. 1753 - 1757,5
(2013/04/10)
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- Iron(II) bromide-catalyzed intramolecular c-h bond amination [1,2]-shift tandem reactions of aryl azides
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Iron(II) bromide catalyzes the transformation of ortho-substituted aryl azides into 2,3-disubstituted indoles through a tandem ethereal C-H bond amination [1,2]-shift reaction. The preference for the 1,2-shift component of the tandem reaction was established to be Me 1 2 Ph.
- Nguyen, Quyen,Nguyen, Tuyen,Driver, Tom G.
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supporting information
p. 620 - 623
(2013/03/13)
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- Oxidative palladium(II)-catalyzed dehydrogenative C-H/C-H cross-coupling of 2,3-substituted indolines with arenes at the C7 position
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Directed directing group: The C7 position of the indoline nucleus is difficult to address in C-H activation. An oxidative palladium(II) catalysis that allows for cross-dehydrogenative coupling in that position with activation of the C-H bond of the arene component is disclosed here. This C-H/C-H cross-coupling is applicable to various indolines acetylated at the nitrogen atom. Substitution at C2 is crucial for the C-H activation to occur at C7 (see scheme).
- Jiao, Lin-Yu,Oestreich, Martin
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supporting information
p. 10845 - 10848
(2013/09/02)
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- Improved indole syntheses from anilines and vicinal diols by cooperative catalysis of ruthenium complex and acid
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By developing a new and efficient dinuclear catalyst [Ru(CO) 2(Xantphos)]2 [Xantphos = 4,5-bis(diphenylphosphino)-9,9- dimethyl-9H-xanthene], an improved synthesis of indole from vicinal diols and anilines by cooperative catalysis of ruthenium complex and p-TSA (para-toluenesufonic acid) has been demonstrated. The presented synthetic protocol allows assembling a wide range of products in an efficient manner. Comparing to the existed protocols, our indole syntheses can be achieved at lower reaction temperature, in shorter reaction time, and with improved substrate tolerance.
- Zhang, Min,Xie, Feng,Wang, Xiaoting,Yan, Fengxia,Wang, Ting,Chen, Mengmeng,Ding, Yuqiang
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p. 6022 - 6029
(2013/05/09)
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- Stereoselective synthesis of 2,3-disubstituted indoline diastereoisomers by chemoenzymatic processes
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Racemic indolines including a variety of structural motifs such as C-2 and C-3 substitutions (alkyl or aryl), cis/trans relative stereochemistry and functionalization of the aromatic ring (fluoro, methyl or methoxy groups) have been efficiently prepared through Fischer indolization and subsequent diastereoselective reduction of the unprotected indoles. Combination of Candida antarctica lipase type A and allyl 3-methoxyphenyl carbonate has been identified as the best tandem for their kinetic resolutions, observing excellent stereodiscriminations for most of the tested indolines.
- Lopez-Iglesias, Maria,Busto, Eduardo,Gotor, Vicente,Gotor-Fernandez, Vicente
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p. 8049 - 8055,7
(2020/10/15)
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- Efficient construction of fused indolines with a 2-quaternary center via an intramolecular heck reaction with a low catalyst loading
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An efficient construction of fused indolines with a 2-quaternary center through a palladium-catalyzed intramolecular Heck reaction of N-(2(2-halobenzoxyl)-2,3-disubstituted indoles is disclosed. This protocol provided a straightforward access to diverse fused indolines with good functional group tolerance.
- Zhao, Lei,Li, Ziyuan,Chang, Lin,Xu, Jinyi,Yao, Hequan,Wu, Xiaoming
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supporting information; scheme or table
p. 2066 - 2069
(2012/06/18)
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- Fischer indole synthesis with organozinc reagents
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Updated classic: Primary and secondary alkylzinc reagents add to various aryldiazonium salts leading regioselectively to polyfunctional indoles by means of a [3,3]-sigmatropic shift and subsequent aromatization. This organometallic variation of the Fischer indole synthesis tolerates a wide range of functional groups and displays absolute regioselectivity. Copyright
- Haag, Benjamin A.,Zhang, Zhi-Guang,Li, Jin-Shan,Knochel, Paul
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supporting information; experimental part
p. 9513 - 9516
(2011/02/24)
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- Iridium- and ruthenium-catalysed synthesis of 2,3-disubstituted indoles from anilines and vicinal diols
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A straightforward and atom-economical method is described for the synthesis of 2,3-disubstituted indoles. Anilines and 1,2-diols are condensed under neat conditions with catalytic amounts of either [Cp*IrCl2] 2/MsOH or RuCl3·xH2O/phosphine (phosphine = PPh3 or xantphos). The reaction does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Anilines containing methyl, methoxy, chloro and fluoro substituents can participate in the cyclocondensation. Meta-substituted anilines give good regioselectivity for 6-substituted indoles, while unsymmetrical diols afford excellent regioselectivity for the indole isomer with an aryl or large alkyl group in the 2-position. The mechanism for the cyclocondensation presumably involves initial formation of the α-hydroxyketone from the diol. The ketone subsequently reacts with aniline to generate the α-hydroxyimine which rearranges to the corresponding α-aminoketone. Acid- or metal-catalysed electrophilic ring-closure with the release of water then furnishes the indole product.
- Tursky, Matyas,Lorentz-Petersen, Linda L. R.,Olsen, Lasse B.,Madsen, Robert
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experimental part
p. 5576 - 5582
(2011/02/18)
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- Rhodium(I)-catalyzed synthesis of indoles: Amino-claisen rearrangement of N-propargylanilines
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Mild and facile preparations of 2-substituted or 2,3-disubstituted indole compounds were achieved by RhH(CO)(Ph3P)3 (4-10 mol %)-catalyzed reaction of N-propargylanilines in hexafluoroisopropyl alcohol (HFIP). The formation of indole
- Saito, Akio,Oda, Shoko,Fukaya, Haruhiko,Hanzawa, Yuji
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scheme or table
p. 1517 - 1524
(2009/07/17)
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- Efficient and straightforward synthesis of tetrahydrocarbazoles and 2,3-dimethyl indoles catalyzed by CAN
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A simple protocol was established to synthesize 2,3-dialkyl indoles and various tetrahydrocarbazoles via Fischer indole synthesis. This method uses ceric ammonium nitrate as a catalyst for the Fischer indole synthesis with substituted phenyl hydrazine hydrochlorides and 2-butanone, phenyl propanal, and cyclohexanone. This process is a practical synthetic method for the preparation of various 2,3-disubstituted alkyl indoles and tetrahydrocarbazoles. Copyright Taylor & Francis Group, LLC.
- Varma, P. Prabhakara,Sherigara, Bailure S.,Mahadevan, Kittapa M.,Hulikal, Vijaykumar
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experimental part
p. 158 - 165
(2009/04/07)
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- Antimony (III) sulfate catalyzed one-pot synthesis of 2,3- disubstitutedindoles
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A novel one-pot Fischer indole synthesis approach has been developed by using antimony (III) sulfate as the catalyst. Good yields were obtained after reacting phenylhydrazines hydrochlorides and ketones in refluxing methanol. The exclusive formation of 2,3- disubstituted indoles was observed in the reaction of ethyl methyl ketone with phenylhydrazines. One-pot synthesis of indole-3-propanol using dihydropyran has also been described. The use of reusable antimony (III) sulfate as a catalyst makes this method both economically and environmentally friendly.
- Srinivasa,Mahadevan,Varma, P. Prabhakara,Sudhakara
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experimental part
p. 1843 - 1853
(2010/02/28)
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- Bismuth nitrate promoted fischer indole synthesis: A simple and convenient approach for the synthesis of alkyl indoles
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A novel one-pot fisher indole synthesis approach has been developed by using bismuth nitrate as a catalyst. Yields around 90-95% were obtained after reaction in methanol at reflux temperature in 20-40 min. Apart from the mild reaction conditions of the process and its excellent results, the simplicity of product isolation and the possibility to recycle the bismuth nitrate offers a significant advantage.
- Sudhakara, Aralihalli,Jayadevappa, Honnali,Kumar, Hosanagara N.H.,Mahadevan, Kittappa M.
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scheme or table
p. 159 - 164
(2010/04/23)
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- Oxidative cleavage reaction of substituted indoles catalyzed by plant cell cultures
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We have developed a novel method for the oxidative cleavage of indole carbon double bonds in the presence of H2O2 using plant cell cultures as peroxidase. The oxidative method has some advantage, as features such as mild reactions, good yields, easy work-up and safety.
- Takemoto, Masumi,Iwakiri, Yasutaka,Tanaka, Kiyoshi
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p. 373 - 383
(2008/03/12)
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- Expedient synthesis of indoles from N-Boc arylhydrazines
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The readily available N-Boc arylhydrazines undergo efficient Fischer cyclizations to provide the indoles in good yields, when reacted with enolizable ketones.
- Lim, Young-Kwan,Cho, Cheon-Gyu
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p. 1857 - 1859
(2007/10/03)
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- Intramolecular cyclization reactions of unsaturated amino Fischer chromium carbenes forming indoles and quinolines
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A thermally induced intramolecular annulation reaction of N-(2-alkenylphenyl)amino substituted Fischer chromium carbenes has been extensively examined. The carbene complexes were prepared in moderate to good yields by reaction of 2-aminostyrenes with intermediately formed acyloxy substituted carbenes. Upon heating, the thermally labile carbenes decomposed producing indoles and quinolines as the major products. The product distribution was found to be highly dependent on the substitution pattern and electronic properties of the starting material, and on the solvent used.
- S?derberg, Bj?rn C. G.,Shriver, James A.,Cooper, Seth H.,Shrout, Timothy L.,Helton, E. Scott,Austin, Lucinda R.,Odens, Herman H.,Hearn, Brian R.,Jones, Paula C.,Kouadio, Tiara N.,Ngi, Tan H.,Baswell, Rachel,Caprara, H. John,Meritt, Mark D.,Mai, Than T.
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p. 8775 - 8791
(2007/10/03)
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- A practical one-pot synthesis of 2,3-disubstituted indoles from unactivated anilines
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2-Substituted-3-methyl indoles are synthesized with good regioselectivity from readily available substrates and catalysts, i.e. the reaction of anilines with propargyl alcohols in the presence of 0.36-1 mol% Ru3(CO)12.
- Tokunaga, Makoto,Ota, Mitsuru,Haga, Masa-aki,Wakatsuki, Yasuo
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p. 3865 - 3868
(2007/10/03)
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- Preparation of Quinone Imine Ketals via Intramolecular Condensation of Amino-Substituted Quinone Monoketals. Anodic Oxidation Chemistry of Trifluoracetamide Derivatives of 1,4-Dimethoxybenzenes and 4-Methoxyphenols
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Two routes have been developed to the previously unknown quinone imine ketal moiety.One involves a sequence of anodic oxidation of the N-trifluoroacetamide of a 2-(2,5-dimethoxyphenyl)ethylamine or 3-(2,5-dimethoxyphenyl)propylamine derivative to form the respective quinone bisketal followed by basic hydrolysis of the trifluoroacetamide linkage, acidic hydrolysis of the quinone bisketal to a quinone monoketal, and intramolecular condensation to form the quinone imine ketal.This method reuires an additional substituent at the 4-position (bromine or methoxy) to direct the regiochemistry of the quinone bisketal hydrolysis.The second method involves similar chemistry except that the anodic oxidation of a 4-methoxyphenol derivative directly affords the quinone monoketal.Hydrolysis of the trifluoroacetamide followed by an intramolecular condensation reaction affords the quinone imine ketal.Selected aspects of the chemistry of these compounds have been studied.Especially interesting is the reaction of a model quinone imine ketal with organolithium reagents.Either 1- or 2-substituted-5-methoxyindole is produced, depending upon the organolithium compound.
- Swenton, John S.,Shih, Chuan,Chen, Chung-Pin,Chou, Chun-Tzer
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p. 2019 - 2026
(2007/10/02)
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- Ruthenium Complex Catalyzed N-Heterocyclization. Syntheses of Quinolines and Indole Derivatives from Aminoarenes and 1,3-Propanediol of Glycols
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Aniline reacts with 1,3-propanediol under reflux in diglyme with spontaneous hydrogen evolution in the presence of a catalytic amount of ruth enium trichloride hydrate ( RuCl3*nH2O)-tributylphosphine (PBu3) to give quinoline in good yield.The yield of quinoline was markedly affected by the molar ratios of aniline to 1,3-propanediol and PBu3 to RuCl3*nH2O.The best yield (76percent) was achieved at the molar ratios of 2.5 of aniline / 1,3-propanediol and 2.0 of PBu3 / RuCl3*nH2O.Also, N-substituted anilines react with ethylene glycol in the presence of a catalytic amount of dichlor otris(triphenylphosphine)ruthenium (RuCl2(PPh3)3) to give N-substituted indole derivatives.The reactions were carried out at 180 deg C in dioxane with spontaneus hydrogen evolution.Aminoarenes also react with 2,3-butanediol and 1,2-cyclohexanediol ( mixture of cis and trans ) in the presence of RuCl2(PPh3)3 to give the corresponding 2,3-dimethylindoles and 1,2,3,4-tetrahydrocarbazoles in good to excellent yields.As the key intermediates of the reactions, N,N'-diarylpropylenediamine (5a) and N,N'-diarylethylenediamine (5b) and their dehydrogenated imine derivatives are postulated.
- Tsuji, Yasushi,Huh, Keun-Tae,Watanabe, Yoshihisa
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p. 1673 - 1680
(2007/10/02)
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