- Regioselective Formation of Substituted Indoles: Formal Synthesis of Lysergic Acid
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A Diels–Alder reaction-based strategy for the synthesis of indoles and related heterocycles is reported. An intramolecular cycloaddition of alkyne-tethered 3-aminopyrones gives 4-substituted indolines in good yield and with complete regioselectivity. Additional substitution is readily tolerated in the transformation, allowing synthesis of complex and non-canonical substitution patterns. Oxidative conditions give the corresponding indoles. The strategy also allows the synthesis of carbazoles. The method was showcased in a formal synthesis of lysergic acid.
- Beaudry, Christopher M.,Points, Gary L.,Stout, Kenneth T.
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supporting information
p. 16655 - 16658
(2020/12/01)
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- DMSO/t-BuONa/O2-Mediated Aerobic Dehydrogenation of Saturated N-Heterocycles
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Aromatic N-heterocycles such as quinolines, isoquinolines, and indolines are synthesized via sodium tert-butoxide-promoted oxidative dehydrogenation of the saturated heterocycles in DMSO solution. This reaction proceeds under mild reaction conditions and has a good functional group tolerance. Mechanistic studies suggest a radical pathway involving hydrogen abstraction of dimsyl radicals from the N-H bond or α-C-H of the substrates and subsequent oxidation of the nitrogen or α-aminoalkyl radicals.
- Cai, Hu,Tan, Wei,Xie, Yongfa,Yang, Ruchun,Yue, Shusheng
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p. 7501 - 7509
(2020/07/07)
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- Superhydrophobic nickel/carbon core-shell nanocomposites for the hydrogen transfer reactions of nitrobenzene and N-heterocycles
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In this work, catalytic hydrogen transfer as an effective, green, convenient and economical strategy is for the first time used to synthesize anilines and N-heterocyclic aromatic compounds from nitrobenzene and N-heterocycles in one step. Nevertheless, how to effectively reduce the possible effects of water on the catalyst by removal of the by-product water, and to further introduce water as the solvent based on green chemistry are still challenges. Since the structures and properties of carbon nanocomposites are easily modified by controllable construction, a one step pyrolysis process is used for controllable construction of micro/nano hierarchical carbon nanocomposites with core-shell structures and magnetic separation performance. Using various characterization methods and model reactions the relationship between the structure of Ni?NCFs (nickel-nitrogen-doped carbon frameworks) and catalytic performance was investigated, and the results show that there is a positive correlation between the catalytic performance and hydrophobicity of catalysts. Besides, the possible catalytically active sites, which are formed by the interaction of pyridinic N and graphitic N in the structure of nitrogen-doped graphene with the surfaces of Ni nanoparticles, should be pivotal to achieving the relatively high catalytic performance of materials. Due to its unique structure, the obtained Ni?NCF-700 catalyst with superhydrophobicity shows extraordinary performances toward the hydrogen transfer reaction of nitrobenzene and N-heterocycles in the aqueous state; meanwhile, it was also found that Ni?NCF-700 still retained its excellent catalytic activity and structural integrity after three cycles. Compared with traditional catalytic systems, our catalytic systems offer a highly effective, green and economical alternative for nitrobenzene and N-heterocycle transformation, and may open up a new avenue for simple construction of structure and activity defined carbon nanocomposite heterogeneous catalysts with superhydrophobicity.
- Duan, Zhiying,Liu, Fangfang,Pang, Shaofeng,Su, Qiong,Wang, Yanbin,Xie, Xin,Zhang, Ping,Zhang, Yujing,Zhou, Feng
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p. 1996 - 2010
(2020/04/07)
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- A indole compound and its preparation method and application (by machine translation)
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The invention discloses a indole compound and its preparation method and application. The indole compounds of the structural formula such as formula (I) is shown. The indoles, rice galenical demonstrate the excellent inhibitory activity, the effect of most of the compound is obviously better than the positive control drug validamycin; especially compound I - 43, I - 44, I - 54, I - 73, II - 7 and II - 17, its galenical very good living body protection and treating effect, effect is better than the positive control; more specifically, compound I - 43 of the rice sheath blight bacteriostatic activity than validamycin activity is improved by nearly 300 times. The indole compounds in the prevention and/or treatment of rice sheath blight has great application prospects. In addition the compound of the invention is simple in construction, the preparation method is simple, and is suitable for large-scale industrial production. (I). (by machine translation)
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Paragraph 0131; 0138; 0139
(2018/10/02)
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- Half-sandwich structured ruthenium complex and preparation method thereof, and method for reducing o-nitrobenzene ethanol compound into indole compound
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The invention discloses a half-sandwich structured ruthenium complex and a preparation method thereof, and a method for reducing an o-nitrobenzene ethanol compound into an indole compound. The structure of the ruthenium complex is as shown in formula (A), wherein in the formula (A), X is halogen, R is H, -oxyl, halogen or nitro, and n is a positive integer ranging from 1 to 4. By the adoption of the preparation method, the ruthenium complex with excellent chemical stability can be obtained; meanwhile, the preparation method has the advantages of simple operation, low equipment requirement and batch production; furthermore, the ruthenium complex can be used as a catalyst for catalytically reducing the o-nitrobenzene ethanol compound (Refer to Specification).
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Paragraph 0080; 0087
(2017/07/22)
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- Dehydrogenation of Nitrogen Heterocycles Using Graphene Oxide as a Versatile Metal-Free Catalyst under Air
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Graphene oxide (GO) has been developed as an inexpensive, environmental friendly, metal-free carbocatalyst for the dehydrogenation of nitrogen heterocycles. Valuable compounds, such as quinoline, 3,4-dihydroisoquinoline, quinazoline, and indole derivatives, have been successfully used as substrates. The investigation of various oxygen-containing molecules with different conjugated systems indicated that both the oxygen-containing groups and large π-conjugated system in GO sheets are essential for this reaction. (Figure presented.).
- Zhang, Jingyu,Chen, Shiya,Chen, Fangfang,Xu, Wensheng,Deng, Guo-Jun,Gong, Hang
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supporting information
p. 2358 - 2363
(2017/07/22)
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- 4 - bromo - 2 - hydroxy indole synthesis method (by machine translation)
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The present invention provides 4 - bromo - 2 - hydroxy indole synthesis method, its steps are as follows: (1) the aluminum powder and zirconium oxide grinding ball into the ball mill pot ball grinding pre-processing aluminum powder; (2) hydrogenation the sodium uses pentane is pretreated pre-processing sodium hydride; (3) the pre-processing of aluminum powder and pretreatment sodium hydride, zirconium oxide grinding ball, to join the ball rubs the pot ball grindingnitric acid titanium, products of sodium aluminum hydride; (4) there will be aluminum nitrate, nitrate by the sol - gel process compound indium catalyst; (5) the α - (N, N - dimethylamino) - 2 - bromo - 6 nitrobenzene ethylene for the cyclization catalyst reduction compound indium prepared 4 - bromo indole; (6) the 4 - bromo indole with oxalyl, methanol prepared through the reaction of 4 - bromo indole - 2 - carboxylic acid; (7) will be 4 - bromo indole - 2 - carboxylic acid is sodium aluminum hydride reduction to obtain the target product. The invention of high yield, low cost. (by machine translation)
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Paragraph 0062; 0068
(2017/04/27)
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- Dehydrogenative N-heterocyclization of 2-(2-aminoaryl)ethyl alcohols to indole derivatives catalyzed by (μ-oxo)tetraruthenium cluster/1,2- bis(diphenylphosphino)benzene
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A novel catalyst system of (μ-oxo)tetraruthenium cluster (2) combined with 1,2-bis(diphenylphosphino)benzene (dppbz) realized a simple, selective, and practical synthesis of indole and its derivatives from 2-(2-aminoaryl)ethyl alcohols via dehydrogenative N-heterocyclization reaction. Spontaneous formation of a stoichiometric amount of hydrogen (H2) was observed, and the present reaction proceeded smoothly under an argon atmosphere without oxidants and/or hydrogen acceptors.
- Kondo, Teruyuki,Kanda, Takashi,Takagi, Daisuke,Wada, Kenji,Kimura,Toshimitsu, Akio
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p. 1015 - 1022
(2013/08/15)
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- A systematic study of two complementary protocols allowing the general, mild and efficient deprotection of N-pivaloylindoles
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Two mild and general protocols for the high-yielding deprotection of indoles and related fused heterocyclic systems are described, involving either hydride transfer from LDA or hydrolysis by the DBU-water system. Both methods were shown to tolerate a wide variety of substituents and functional groups, but the hydrolytic one proved to be particularly general, being compatible with 2-alkyl substituents, aldehydes, ketones, carboxylic acids, halogens, ethers, amides and esters. Yields were normally excellent in both cases, but were usually slightly higher for the reductive method. Taken together, these two protocols provide a general solution to the problem of pivaloyindole deprotection.
- Ruiz, Míriam,Sánchez, J. Domingo,López-Alvarado, Pilar,Menéndez, J. Carlos
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experimental part
p. 705 - 710
(2012/01/06)
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- A total synthesis of (±)-α-cyclopiazonic acid using a cationic cascade as a key step
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The indole alkaloid α-cyclopiazonic acid 1 has been synthesised by a route, which features at its core an acid-catalysed cationic cascade cyclisation terminated by a sulfonamide group.
- Griffiths-Jones, Charlotte M.,Knight, David W.
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p. 8515 - 8528
(2011/11/29)
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- An improved palladium-catalyzed conversion of aryl and vinyl triflates to bromides and chlorides
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A facile Pd-catalyzed conversion of aryl and vinyl triflates to aryl and vinyl halides (bromides and chlorides) is described. This method allows convenient access to a variety of aryl, heteroaryl, and vinyl halides in good to excellent yields and with greatly simplified conditions relative to our previous report.
- Pan, Jun,Wang, Xinyan,Zhang, Yong,Buchwald, Stephen L.
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supporting information; experimental part
p. 4974 - 4976
(2011/11/06)
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- Enantioselective N-H functionalization of indoles with α,β- unsaturated γ-lactams catalyzed by chiral Bronsted acids
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Nitrogen revives: Cyclic N-acyliminium ions were generated from α,β-unsaturated γ-lactams (1) and underwent intermolecular addition by indole nucleophiles (2) under the catalysis of a chiral Bronsted acid (3). A variety of N-functionalized indole derivatives containing a pyrrolidinone moiety (4) were assembled with high enantioselectivity. Bn=benzyl. Copyright
- Xie, Yinjun,Zhao, Yingwei,Qian, Bo,Yang, Lei,Xia, Chungu,Huang, Hanmin
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supporting information; experimental part
p. 5682 - 5686
(2011/08/03)
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- Approaches to the synthesis of 2,3-dihaloanilines. Useful precursors of 4-functionalized-1 H-indoles
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2,3-Dihaloanilines have been proved as useful starting materials for synthesizing 4-halo-1H-indoles. Subsequent or in situ functionalization of the prepared haloindoles allows the access to a wide variety of 2,4- or 2,3,4-regioselectively functionalized indoles in good overall yields. As no efficient synthetic routes to 2,3-dihaloanilines have been described in the literature, different approaches to the preparation of these 1,2,3-functionalized aromatic precursors are now presented. The most general one involves a Smiles rearrangement from the corresponding 2,3-dihalophenols and allows the preparation of 2,3-dihaloanilides in a straightforward and synthetically useful manner.
- Guilarte, Veronica,Castroviejo, M. Pilar,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Sanz, Roberto
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p. 3416 - 3437
(2011/06/28)
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- Synthesis of 4-functionalized-1H-indoles from 2,3-dihalophenols
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A new synthesis of 4-halo-1H-indoles has been developed from easily available 2,3-dihalophenol derivatives. The key steps are Smiles rearrangement and a one-pot or stepwise Sonogashira coupling/NaOH-mediated cyclization. Subsequent functionalization allows access to a wide variety of 2,4- or 2,3,4-regioselectively functionalized indoles.
- Sanz, Roberto,Guilarte, Veronica,Garcia, Nuria
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supporting information; experimental part
p. 3860 - 3864
(2010/09/17)
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- Pd(II)-catalyzed amination of C-H bonds using single-electron or two-electron oxidants
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(Chemical Equation Presented) Pd(II)-catalyzed intramolecular amination of arenes is developed using either a one- or two-electron oxidant. The reaction protocol tolerates a wide range of deactivating groups including acetyl, cyano, and nitro groups. This catalytic reaction allows expedient syntheses of broadly useful substituted indolines or indoles.
- Mei, Tian-Sheng,Wang, Xisheng,Yu, Jin-Quan
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supporting information; experimental part
p. 10806 - 10807
(2009/12/04)
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- Microwave assisted Leimgruber-Batcho reaction for the preparation of indoles, azaindoles and pyrroylquinolines
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The development of enhanced conditions for Lewis acid catalysed Leimgruber-Batcho indole synthesis using microwave acceleration is described. This approach has permitted the preparation of a variety of heteroaromatic enamine intermediates in good yield and high purities. Subsequent catalytic hydrogenation reactions, under various conditions including the use of a solid-phase encapsulated catalyst, furnish the corresponding indole derivatives in good yields.
- Siu, Jason,Baxendale, Ian R.,Ley, Steven V.
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p. 160 - 167
(2007/10/03)
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- A New Synthesis of Lysergic Acid
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(Equation presented) (±)-Lysergic acid (1) has been synthesized via an economical 8-step route from 4-bromoindole and isocinchomeronic acid without the need to protect the indole during the synthesis. Initial efforts to form the simpler 3-acylindole derivatives first and then cyclize these were unsuccessful in the cyclization step.
- Hendrickson, James B.,Wang, Jian
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- Studies toward diazonamide A: Initial synthetic forays directed toward the originally proposed structure
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A brief introduction into the chemistry of diazonamide A (1) is followed by first-generation sequences to access the originally proposed structure for this unusual marine natural product. These explorations identified a route capable of delivering a model compound possessing the complete heteroaromatic core of the natural product, highlighting in the process several unanticipated synthetic challenges which led both to new methodology as well as an improved synthetic plan that was successfully applied to fully functionalized intermediates.
- Nicolaou,Snyder, Scott A.,Huang, Xianhai,Simonsen, Klaus B.,Koumbis, Alexandros E.,Bigot, Antony
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p. 10162 - 10173
(2007/10/03)
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- Indoles
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A 1,4-substituted cyclic amine derivative represented by the following formula or a pharmacologically acceptable salt thereof: wherein A, B, C, D, T, Y, and Z each represent a methine or a nitrogen linkage; R1, R2, R3, R4, and R5 each represent a substituent; n represents 0 or an integer of 1 to 3; m represents 0 or an integer of 1 to 6; and p represents an integer of 1 to 3. The compounds have serotonin antagonism. They are therefore clinically useful as medicaments, in particular, for treating, ameliorating, and preventing spastic paralysis. They are also useful as central muscle relaxants for ameliorating myotonia.
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- Synthesis of the 4-arylindole portion of the antitumor agent diazonamide and related studies
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The synthesis of 6 comprising the CDG rings of the diazonamides was achieved in an overall yield of 75% from commercially available 3. (C) 2000 Elsevier Science Ltd.
- Chan, Fiona,Magnus, Philip,McIver, Edward G.
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p. 835 - 838
(2007/10/03)
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- Palladium-Catalyzed Synthesis of Indoles by Reductive N-Heteroannulation of 2-Nitrostyrenes
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A palladium-phosphine catalyzed reductive N-heteroannulation of 2-nitrostyrenes, in the presence of carbon monoxide, producing indoles has been developed. Indoles were obtained, in moderate to excellent yield, from substituted 2-nitrostyrenes having either electron-withdrawing (NO2 and CO2-Me) or electron-donating (Br, OH, Me, OMe, and OTf) substituents on the aromatic ring. Best results were obtained using palladium diacetate (6 mol percent) together with triphenylphosphine (24 mol percent) as the catalytic system, under 4 atm of carbon monoxide in acetonitrile at 70 °C. Other palladium(II) and palladium(0) complexes also catalyze the reaction.
- So?derberg, Bjo?rn C.,Shriver, James A.
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p. 5838 - 5845
(2007/10/03)
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- Ruthenium-Catalyzed Dehydrogenative N-Heterocyclization: Indoles from 2-Aminophenethyl Alcohols and 2-Nitrophenethyl Alcohols
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Indole derivatives 3 were readily obtained from 2-aminophenethyl alcohols 1 in the presence of 2 mol percent (based on 1) of RuCl2(PPh3)3 under reflux in toluene.Indole (3a) was afforded from 2-aminophenethyl alcohol (1a) quantitatively.Other indoles (3) were also obtained in 73-99percent isolated yields from the corresponding 1, which were easily prepared by condensation between the corresponding 2-nitrotoluenes and aldehydes followed by reduction.During the reaction, a stoichiometric amount of hydrogen was spontaneously evolved into the gas phase.With a heterogeneous and homogeneous binary catalyst system, indoles were afforded in one pot from 2-nitrophenethyl alcohols 2 under a hydrogen atmosphere.
- Tsuji, Yasushi,Kotachi, Shinji,Huh, Keun-Tae,Watanabe, Yoshihisa
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p. 580 - 584
(2007/10/02)
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- Metal-Halogen Exchange of Bromoindoles. A Route to Substituted Indoles
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The 4-, 5-, 6-, and 7-bromoindoles, conveniently synthesized by the Batcho-Leimgruber process, serve as efficient precursors to regiochemically pure lithiated indoles.Metal-halogen exchange was most effective if potassium hydride was used first to remove the acidic indole NH, and tert-butyllithium was used then to effect metal-halogen exchange.The resulting indolyl organometallic reagents react with a variety of electrophiles to give regioisomerically pure acylated indoles.
- Moyer, Mikel P.,Shiurba, John F.,Rapoport, Henry
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p. 5106 - 5110
(2007/10/02)
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- Ruthenium Catalysed N-Heterocyclisation: Indoles from 2-Aminophenethyl Alcohols
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Dichlorotris(triphenylphosphine)ruthenium is highly active as a catalyst for the N-heterocyclisation of 2-aminophenethyl alcohols (2a-d) into indole derivatives in toluene under reflux, and the reactions proceed with spontaneous hydrogen evolution.
- Tsuji, Yasushi,Huh, Keun-Tae,Yokoyama, Yasuharu,Watanabe, Yoshihisa
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p. 1575 - 1576
(2007/10/02)
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- Palladium-Catalyzed Reactions in the Synthesis of 3- and 4-Substituted Indoles. Approaches to Ergot Alkaloids
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An efficient synthesis of 4-bromo-1-tosylindole (10) based on the Pd(II)-catalyzed cyclization of an o-ethenylaniline p-toluenesulfonamide has been developed.A Pd(0) oxidative addition-olefin insertion-β-hydride elimination cycle converted 10 to a number of 4-substituted 1-tosylindoles.Selective electrophilic substitutions at the 3-position of 10 provided access to the 3-(chloromercurio)- (18) and 3-iodo-1-tosylindoles (22).Transmetalation to palladium and allyl chloride insertion converted 18 to 3-allyl-4-bromo-1-tosylindole (20) which could be cyclized to the benzindoline 21.A Pd(0) oxidative addition-olefin insertion-β-hydride elimination cycle converted the 3-iodo compound 22 to a number of 4-bromo-3-substituted 1-tosylindoles including 24, a potential precursor to optically active tryptophans.
- Harrington, Peter J.,Hegedus, Louis S.
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p. 2658 - 2662
(2007/10/02)
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- Synthesis of Substituted Indoles via Meerwein Arylation
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A new method for the synthesis of substituted indoles is detailed.Meerwein arylation of 4- and 6-substituted 2-nitrobenzenediazonium chlorides with vinyl acetate or vinyl bromide and subsequent reductive cyclization of the resulting adducts affords the corresponding 6- and 4-substituted (CH3, OCH3, Cl, Br, CF3) indoles.The diazonium bisulfates of weakly basic 2-nitroanilines (4-Cl, 6-Br, 4-CF3) gave higher yields of Meerwein arylation adducts than the corresponding diazonium chlorides.Coupling of 2-nitrobenzenediazonium chloride with 2-acetoxy-1-alkenes followed byreductive cyclization affords 2-alkylindoles.
- Raucher, Stanley,Koolpe, Gary A.
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p. 2066 - 2069
(2007/10/02)
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