- Method for preparing 5, 6-dihydroxyindole by using modified ordered mesoporous carbon supported metal catalyst
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The invention belongs to the technical field of organic synthesis, and discloses a method for preparing 5, 6-dihydroxyindole by using a modified ordered mesoporous carbon supported metal catalyst. According to the invention, phenolic resin is taken as a carbon source, polyether F127 is taken as a soft template, an ordered mesoporous carbon loaded metal material is prepared as a catalyst, and high catalytic activity and good stability are shown in the reaction of 3, 4-dimethoxyaniline and ethylene glycol. The catalyst prepared by the method has remarkable effects of avoiding agglomeration and stripping of active components, improving the reaction catalytic activity and prolonging the service life. The raw materials are easy to obtain, the cost is low, the product is white powder, the product purity reaches 98.3%, the ethylene glycol conversion rate in the reaction is close to 60%, the selectivity of the 5, 6-dimethoxy indole reaches 85% or above, and the final yield of the 5, 6-dihydroxy indole can reach 81% or above.
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Paragraph 0032-0038; 0041-0047
(2021/05/01)
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- Aerobic Dehydrogenation of N-Heterocycles with Grubbs Catalyst: Its Application to Assisted-Tandem Catalysis to Construct N-Containing Fused Heteroarenes
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An aerobic dehydrogenation of nitrogen-containing heterocycles catalyzed by Grubbs catalyst is developed. The reaction is applicable to various nitrogen-containing heterocycles. The exceptionally high functional group compatibility of this method was confirmed by the oxidation of an unprotected dihydroindolactam V to indolactam V. Furthermore, by taking advantage of the oxygen-mediated structural change of the Grubbs catalyst, we integrated ring-closing metathesis and subsequent aerobic dehydrogenation to develop the novel assisted-tandem catalysis using molecular oxygen as a chemical trigger. The utility of the assisted-tandem catalysis was demonstrated by the concise synthesis of N-containing fused heteroarenes including a natural antibiotic, pyocyanine.
- Kawauchi, Daichi,Noda, Kenta,Komatsu, Yoshiyuki,Yoshida, Kei,Ueda, Hirofumi,Tokuyama, Hidetoshi
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supporting information
p. 15793 - 15798
(2020/10/12)
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- Tandem Wittig – Reductive annulation decarboxylation approach for the synthesis of indole and 2-substituted indoles
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A simple tandem Wittig reaction-reductive decarboxylation route is established for the synthesis of indoles from commercially available o-nitrobenzaldehydes and a stable phosphorane. The method allows access to indoles in a very fast manner without involving any metal or expensive reagents or inert atmosphere. Also 2-substituted indoles are obtained which forms an important core of many biological active compounds.
- Volvoikar, Prajesh S.,Tilve
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supporting information
p. 1851 - 1854
(2018/04/14)
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- Straight Access to Indoles from Anilines and Ethylene Glycol by Heterogeneous Acceptorless Dehydrogenative Condensation
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The development of original strategies for the preparation of indole derivatives is a major goal in drug design. Herein, we report the first straight access to indoles from anilines and ethylene glycol by heterogeneous catalysis, based on an acceptorless dehydrogenative condensation, under noninert conditions. In order to achieve high selectivity, a combination of Pt/Al2O3 and ZnO have been found to slowly dehydrogenate ethylene glycol generating, after condensation with the amine and tautomeric equilibrium, the corresponding pyrrole-ring unsubstituted indoles.
- Llabres-Campaner, Pedro Juan,Ballesteros-Garrido, Rafael,Ballesteros, Rafael,Abarca, Belén
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p. 521 - 526
(2018/01/01)
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- β-Amino alcohols from anilines and ethylene glycol through heterogeneous Borrowing Hydrogen reaction
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Borrowing Hydrogen (BH), also called Hydrogen Autotransfer (HA), reaction with neat ethylene glycol represents a key step in the preparation of β-amino alcohols. However, due to the stability of ethylene glycol, mono-activation has rarely been achieved. Herein, a combination of Pd/C and ZnO is reported as heterogeneous catalyst for this BH/HA reaction. This system results in an extremely air and moisture stable, and economic catalyst able to mono-functionalize ethylene glycol in water, without further activation of the diol. In this work, different diols and aromatic amines have been explored affording a new approach towards amino alcohols. This study reveals how the combination of two solid species can afford interesting catalytic properties in heterogeneous phase. ZnO activates ethylene glycol while Pd/C is the responsible of the BH/HA cycle. This catalytic system has also been found useful to dehydrogenate indoles affording indolines that undergo in situ BH/HA cycle prior to re-aromatization, representing a tandem heterogeneous process.
- Llabres-Campaner, Pedro J.,Ballesteros-Garrido, Rafael,Ballesteros, Rafael,Abarca, Belén
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supporting information
p. 5552 - 5561
(2017/08/22)
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- Active and Recyclable Catalytic Synthesis of Indoles by Reductive Cyclization of 2-(2-Nitroaryl)acetonitriles in the Presence of Co-Rh Heterobimetallic Nanoparticles with Atmospheric Hydrogen under Mild Conditions
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A cobalt-rhodium heterobimetallic nanoparticle-catalyzed reductive cyclization of 2-(2-nitroaryl)acetonitriles to indoles has been achieved. The tandem reaction proceeds without any additives under the mild conditions (1 atm H2 and 25 °C). This procedure could be scaled up to the gram scale. The catalytic system is significantly stable under these reaction conditions and could be reused more than ten times without loss of catalytic activity.
- Choi, Isaac,Chung, Hyunho,Park, Jang Won,Chung, Young Keun
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supporting information
p. 5508 - 5511
(2016/11/17)
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- Catalytic synthesis method of indole compounds
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The invention discloses a catalytic synthesis method of indole compounds.The method includes the following steps of firstly, conducting stirring reaction on ortho-nitrostyrolene or derivatives of ortho-nitrostyrolene, bis(pinacolato)diboron, alkali and low-grade saturated monohydric alcohol under the atmosphere of nitrogen; secondly, cooling the reaction product in the first step to the room temperature, adding ethyl acetate to be sufficiently mixed, and washing with ethyl acetate after filtering; thirdly, spin-drying low-grade saturated monohydric alcohol in an organic phase of the material obtained in the second step, passing through a silica gel column, and drip washing the silica gel column with eluent composed of petroleum ether and ethyl acetate to obtain pure products, namely, the indole compounds.By means of the method, under the neutral conditions, bis(pinacolato)diboron low in price serves as the raw material, friendly low-grade saturated monohydric alcohol serves as the solvent, the indole compounds are obtained through simple operation, the raw materials are low in price and easy to obtain, efficiency and safety are high, and wide expandability and good industrial application prospects are achieved.
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Paragraph 0024; 0025; 0026; 0027; 0028; 0029; 0030; 0031
(2016/10/10)
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- Phosphane-free Pd0-catalyzed cycloamination and carbonylation with Pd(OAc)2 and Cu(OAc)2 in the presence of K 2CO3: Preparation of benzocyclic amines and benzolactams
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Phosphane-free Pd0-catalyzed intramolecular aromatic amination was studied. o-Halophenethylamines and 3-(o-halophenyl)propylamines were found to be transformed into indolines and quinolines in a catalytic system based on Pd(OAc)2 and Cu(OAc)2 in the presence of K 2CO3. Application of the method to substrates containing isoquinoline rings- the 1-(o-bromobenzyl)-3,4-dihydroisoquinolines 6, the 1-(o-bromobenzyl)-1,2,3,4-tetrahydroisoquinolines 7, and the 1-(o-bromophenethyl)isoquinolines 9- provided the indolo[2,1-a]isoquinoline and dibenzo[a,f]quinolizine ring systems 8 and 10. Extension of the method to β-carbolines (compounds 11, 12, and 17) produced the benz[f]indolo[2,3-a] indolizine-13-ones 15 and the benz[f]indolo[2,3-a]quinolizine 18. The benzo[f]pyrido[3,4-a]indolizine and indolo[f]pyrido[3,4-a]indolizin-12-one ring systems 27 and 31 were built in a similar manner. It was also found that under an atmosphere of CO the same catalytic system produced the corresponding benzolactams, the isoquino[2,1-a][2,7]naphthyridine 34 and the indolo[2,3-a]pyrido[g]quinolizin-8-one 36 [(±)-dihydronauclefine] in good yields. Copyright
- Harada, Rika,Nishida, Naoto,Uchiito, Shiho,Onozaki, Yu,Kurono, Nobuhito,Senboku, Hisanori,Masao, Tokuda,Ohkuma, Takeshi,Orito, Kazuhiko
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p. 366 - 379
(2012/02/04)
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- Concise, efficient and practical assembly of bromo-5,6-dimethoxyindole building blocks
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A concise, efficient and simple route to a series of bromoindole building blocks is described. The synthetic routes are highlighted by purification-free preparation of o-nitrocinnamate intermediates and clean, modified Cadogan indole syntheses. The scope of this indole synthesis has been explored and expanded through the use of a range of solvents and easily removable phosphine reagents.
- Huleatt, Paul B.,Lau, Jacelyn,Chua, Sheena,Tan, Yun Lei,Duong, Hung Anh,Chai, Christina L.L.
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experimental part
p. 1339 - 1342
(2011/03/22)
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- Effects of indole fatty alcohols on the differentiation of neural stem cell derived neurospheres
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In a search for inducers of neuronal differentiation to treat neurodegenerative diseases such as Alzheimer's disease, a series of indole fatty alcohols (IFAs) were prepared, 13c (n = 18) was able to promote the differentiation of neural stem cell derived neurospheres into neurons at a concentration of 10 nM. Analysis of the expression of the Notch pathway genes in neurospheres treated during the differentiation phase with 13c (n = 18) revealed a significant decrease in the transcription of the Notch 4 receptor.
- Coowar, Djalil,Bouissac, Julien,Hanbali, Mazen,Paschaki, Marie,Mohier, Eliane,Luu, Bang
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p. 6270 - 6282
(2007/10/03)
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- The synthesis of roeharmine and (-)-1,2,3,4-tetrahydroroeharmine
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The total synthesis of roeharmine 1 as well as an enantiospecific synthesis of (-)-1,2,3,4-tetrahydroroeharmine 2 has been achieved via the Pictet-Spengler reaction as a key step. The optical rotation of synthetic (- )-2 was found to be higher than that reported for the natural product. A possible mechanism for the racemization of 2 upon exposure to acid has been proposed and serves as a warning to alkaloid chemists who isolate ring-A alkoxylated indole alkaloids under acidic conditions.
- Sreenivasa Reddy,Cook, James M.
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p. 5413 - 5416
(2007/10/02)
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- Product based on inorganic or organic lamellar particles, containing a melanotic pigment, process for preparing it and its use in cosmetics
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The invention relates to a product in powder form consisting of organic or inorganic particles having a lamellar structure, having a size of less than 50 microns and containing at least one synthetic melanotic pigment formed in situ by oxidation of an indole compound, and to its use for the protection of the human epidermis, in make-up products and for dyeing hair.
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- A GENERAL FORMATION OF QUINONE IMINES AND QUINONE IMINE ACETALS: AN EFFICIENT SYNTHESIS OF 5-OXYGENATED INDOLES
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A general and high-yield synthesis of benzoquinone imines and benzoquinone imine monoacetals leading to 5-oxygenated indoles was developed.
- Kita, Yasuyuki,Tohma, Hirofumi,Inagaki, Masanao,Hatanaka, Kenji
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p. 503 - 506
(2007/10/02)
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- Substituent Effects on the Spectral, Acid-Base, and Redox Properties of Indolyl Radicals: A Pulse Radiolysis Study
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Spectral and acid-base properties and reduction potentials of various substituted indolyl radicals were studied by pulse radiolysis in aqueous solutions at 20 deg C.Except for the 5-methoxyindolyl and 5-carboxyindolyl radicals, the spectra of the substituted indolyl radicals resemble the previously published 320- and 520-nm spectra of the neutral and 330- and 580-nm spectra of the cation indolyl and tryptophan radicals.The substitution of indolyl radical cation by electron-attracting groups (positive ?+) results in a blue shift of the 580-nm band by ca. 30 nm,, whereas the spectra of methylindolyl (?+ = -0.31) are similar to those of unsubstituted indolyl radicals.The 430- and 455-nm bands appearing in the spectra of the 5-carboxyindolyl and 5-methoxyindolyl radical cations, respectively, indicate even stronger interaction of the unpaired electron with the 5-substituent.The radical cations of various indole-3-acetic acids decarboxylate at pH values below their pKa to produce allyl radicals.The 5-bromoindolyl radical undergoes solvolysis to 5-hydroxyindolyl radical in acidic and alkaline media.The dissociation constants and reduction potentials of the substituted indolyl radicals correlate with the Brown substituent constants: pKr = 4.14 - 2.13Σ?+, correlation coefficient 0.987, and E0/0.059 = 22.29 + 3.5Σ?+, correlation coefficient 0.980.The ρ values from these correlations (-2.13 and 3.5) are similar to that of the Hammett correlation of the dissociation constants of the protonated indole nitrogen in various substituted indoles, ρ = -2.49, but smaller than the ρ value of the dependence on the substituent of the reduction potentials of phenoxyl radicals, ρ = 5.4.
- Jovanovic, Slobodan V.,Steenken, Steen
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p. 6674 - 6679
(2007/10/02)
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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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- A GENERAL APPROACH TO QUINONE IMINE KETALS. INTERESTING INTERMEDIATES FOR PREPARATION OF 5-OXYGENATED INDOLES AND QUINONE IMINES
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A general route for the preparation of quinone imine ketals is reported.
- Chen, Chung-Pin,Shih, Chuan,Swenton, John S.
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p. 1891 - 1894
(2007/10/02)
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- 3,5- And 5,5-bis(3-indolyl)-2-(5H)furanones
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Mono-, bis- and tris-indolyl-substituted furanones useful as color formers, particularly in carbonless duplicating and thermal marking systems, which are prepared respectively by: the interaction of an indole with mucochloric acid; the interaction of an indole with a 4-mono(indolyl-substituted 4-oxo-2-butenoic acid; and by the interaction of an indole with a 2,4-bis(indolyl)-substituted 4-oxobutanoic acid or with a 3,5-bis(indolyl)-substituted furanone.
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- Indolyl phthalide compounds
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3-Aryl-3-indolylphthalides, 3-aryl-3-pyrrolylphthalides and 3-aryl-3-carbazolylphthalides prepared by interaction of the appropriate 2-(heteroaryl)carbonylbenzoic acid and the appropriate phenylamine, and 3,3-bis(indolyl)phthalides prepared by the interaction of the appropriate 2-(indolyl)carbonylbenzoic acid and the appropriate indole are useful as color formers in pressure-sensitive carbonless duplicating systems, thermal marking systems and hectographic copying systems.
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- Studies on the Syntheses of Heterocyclic Compounds. Part 865. A Novel Synthesis of Indole Derivatives by Intramolecular Nucleophilic Aromatic Substitution
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Cyclisation of N-(2-bromo-4,5-dimethoxyphenethyl)acetamide (6) afforded 1-acetyl-2,3-dihydro-5,6-dimethoxy-1H-indole (13) by intramolecular nucleophilic aromatic substitution using sodium hydride and cuprous halide in dimethylformamide.The dihydroindoles (14), (15), and (16) were also synthesised from the corresponding amides (8) and (10) and the carbamate (12) in a similar manner.The dihydroindoles (13), (14), and (16) were converted into the indoles (20) and (21) in excellent yield by oxidation and subsequent alkaline hydrolysis.The 2-oxindoles (26) and (27) were also prepared under similar reaction condition from the phenylacetamide (24) and (25).
- Kametani, Tetsuji,Ohsawa, Tatsushi,Ihara, Masataka
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p. 290 - 294
(2007/10/02)
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- Novel compounds, processes and marking systems
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Mono and bis substituted (arylsulfonyl)alkanes useful as color formers, particularly in carbonless duplicating and thermal marking systems, are prepared by the interaction of the appropriate aldehyde or dialdehyde with the appropriate aryl or heterocyclic moiety and the appropriate phenylsulfinic acid in the presence of a catalyst.
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- Heteroarylphthalides
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3-Aryl-3-indolylphthalides, 3-aryl-3-pyrrolylphthalides and 3-aryl-3-carbazolylphthalides prepared by interaction of the appropriate 2-(heteroaryl)carbonylbenzoic acid and the appropriate phenylamine, and 3,3-bis(indolyl)-phthalides prepared by the interaction of the appropriate 2-(indolyl)carbonylbenzoic acid and the appropriate indole are useful as color formers in pressure-sensitive carbonless duplicating systems, thermal marking systems and hectographic copying systems.
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- Phthalide compounds, processes and marking systems
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3-Aryl-3-indolylphthalides, 3-aryl-3-pyrrolylphthalides and 3-aryl-3-carbazolylphthalides prepared by interaction of the appropriate 2-(heteroaryl)carbonylbenzoic acid and the appropriate phenylamine, and 3,3-bis(indolyl)phthalides prepared by the interaction of the appropriate 2-(indolyl)carbonylbenzoic acid and the appropriate indole are useful as color formers in pressure-sensitive carbonless duplicating systems, thermal marking systems and hectographic copying systems.
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- 3,5-Bis (indolyl)-5-(indolyl)-2(5H)-furanones
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Mono-, bis- and tris-indolyl-substituted furanones useful as color formers, particularly in carbonless duplicating and thermal marking systems, which are prepared respectively by: the interaction of an indole with mucochloric acid; the interaction of an indole with a 4-mono(indolyl)-substituted 4-oxo-2-butenoic acid; and by the interaction of an indole with a 2,4-bis(indolyl)-substituted 4-oxobutanoic acid or with a 3,5-bis(indolyl)-substituted furanone.
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- Intermediates for indoles
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Ortho-nitrotoluenes are condensed with formamide acetals to yield the corresponding otho-nitro-β-aminestyrenes which undergo cyclization upon reduction to yield indoles.
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