cas 6146-52-7, 5-Nitroindole | Articles data

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Deprotonation of 5-Nitroindole in Micellized Cetyltrimethylammonium Bromide and Hydroxide
The fraction, f, of deprotonation of 5-nitroindole (BH) in cetyltrimethylammonium bromide (CTABr) and NaOH goes through maxima with .In CTAOH micelles f increases smoothly with , even when the indicator is fully micellar bound, and is increased by added NaOH.These variations of f follow the concentrations of BH and OH- in the cationic micelles and the basicity constant in the micellar pseudophase is smaller than in water by a factor of ca. 5.
Cipiciani, Antonio,Savelli, Gianfranco,Bunton, Clifford A.
p. 5259 - 5261
(1983)
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Aerobic Dehydrogenation of N-Heterocycles with Grubbs Catalyst: Its Application to Assisted-Tandem Catalysis to Construct N-Containing Fused Heteroarenes
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
supporting information
p. 15793 - 15798
(2020/10/12)

Visible-Light-Promoted Efficient Aerobic Dehydrogenation of N-Heterocycles by a Tiny Organic Semiconductor Under Ambient Conditions
An efficient reusable catalytic system has been developed based on perylene diimide (PDI) organic semiconductor for the aerobic dehydrogenation of N-heterocycles with visible light. This practical catalytic system without any additives proceeds under ambient conditions. The minute aggregates of PDI molecules on the surface of SiO2 nanospheres form tiny organic semiconductors, resulting in high-efficiency photo-oxidative activity. Notably, the robustness of this method is demonstrated by the synthesis of a wide range of N-heteroarenes, gram-scale experiments as well as reusability tests.
Su, Chenliang,Yu, Kunyi,Zhang, Hanjie,Zhu, Yongfa
supporting information
p. 1956 - 1960
(2020/04/10)

Reusable, homogeneous water soluble photoredox catalyzed oxidative dehydrogenation of N-heterocycles in a biphasic system: Application to the synthesis of biologically active natural products
Herein, a simple and efficient method for the oxidative dehydrogenation (ODH) of tetrahydro-β-carbolines, indolines and tetrahydro-(iso)quinolines is described using a reusable, homogeneous cobalt-phthalocyanine photoredox catalyst in a biphasic medium. A biphasic system offers an advantage of easy separation of the product and an efficient reusability of the homogeneous photoredox catalyst. Also, the current system significantly helps to overcome the solubility issue of the substrate and catalyst at room temperature. Its potential applications to organic transformations are demonstrated by the synthesis of various biologically active N-heterocycles such as indoles, (iso)quinolines and β-carbolines and natural products such as eudistomin U, norharmane, and harmane and precursors to perlolyrine and flazin. Without isolation and purification, the catalyst solution can be reused up to 5 times with almost comparable reactivity. Furthermore, the efficiency of the reaction was demonstrated on a gram scale. To the best of our knowledge, this is the first report on ODH reactions using a non noble, reusable and homogeneous cobalt photoredox catalyst under environmentally friendly conditions.
Abinaya, R.,Baskar, B.,Mariappan, M.,Prasanth, Arun,Sridhar, R.,Srinath, S.
p. 2575 - 2587
(2020/05/13)

Iodine-catalyzed convergent aerobic dehydro-aromatization toward benzazoles and benzazines
An iodine-catalyzed aerobic dehydro-aromatization has been developed, providing straightforward and efficient access to various benzoazoles and benzoazines. The present transition-metal-free protocol enables the dehydro-aromatization of tetrahydrobenzazoles and tetrahydroquinolines with molecular oxygen as the green oxidant, along with some other N-heterocycles. Hence, a broad range of heteroaromatic compounds are generated in moderate to good yields under facile reaction conditions.
Chen, Shanping,Deng, Guo-Jun,Jiang, Pingyu,Ni, Penghui,Tuo, Xiaolong,Wang, Xiaodong
p. 8348 - 8351
(2020/03/11)

Aerobic oxidative dehydrogenation of N-heterocycles over OMS-2-based nanocomposite catalysts: Preparation, characterization and kinetic study
OMS-2-based nanocomposites doped with tungsten were prepared for the first time and their remarkably enhanced catalytic activity and recyclability in aerobic oxidative dehydrogenation of N-heterocycles were examined in detail. Many tetrahydroquinoline derivatives and a broad range of other N-heterocycles could be tolerated by the catalytic system using a biomass-derived solvent as a reaction medium. Newly generated mixed crystal phases, noticeably enhanced surface areas and labile lattice oxygen of the OMS-2-based nanocomposite catalysts might contribute to their excellent catalytic performance. Moreover, a kinetic study was extensively performed which concluded that the dehydrogenation of 1,2,3,4-tetrahydroquinoline is a first-order reaction, and the apparent activation energy is 29.66 kJ mol-1
Bi, Xiuru,Tang, Tao,Meng, Xu,Gou, Mingxia,Liu, Xiang,Zhao, Peiqing
p. 360 - 371
(2020/02/04)

Exploring the Labile Nature of 2,4,6-Trimethoxyphenyl Moiety in Allylic Systems under Acidic Conditions
An investigation of the unexpected lability of the Csp3–Csp2 bond connecting 2,4,6-trimethoxyphenyl group and an allylic moiety is carried out. We observed that the catalytic presence of either Lewis or Br?nsted acid can render such 2,4,6-trimethoxyphenyl group labile. Several nucleophiles were found to substitute the labile C–C bond in mild reaction conditions resulting in very good yields of the allylated products. Even in the absence of a nucleophile, intramolecular cyclization of the parent substrate under acidic activation caused the labile C–C bond to cleave. A major motivation of this study is to understand the lability of electron-rich aryl group in acidic medium, employing 2,4,6-trimethoxyphenyl moiety as a case study. A plausible mechanism is proposed after carrying out several control reactions as well as UV/Vis and 1H NMR spectroscopic studies. This work provides an insight into the activation of electron-rich arenes as a labile entity in acidic medium while also adding a conceptually novel C–C bond breaking approach to the vast literature of allylation of arenes.
Paul, Dipankar,Chatterjee, Paresh Nath
supporting information
p. 4705 - 4712
(2020/07/28)

Superhydrophobic nickel/carbon core-shell nanocomposites for the hydrogen transfer reactions of nitrobenzene and N-heterocycles
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
p. 1996 - 2010
(2020/04/07)

Efficient acceptorless photo-dehydrogenation of alcohols and: N -heterocycles with binuclear platinum(ii) diphosphite complexes
Although photoredox catalysis employing Ru(ii) and Ir(iii) complexes as photocatalysts has emerged as a versatile tool for oxidative C-H functionalization under mild conditions, the need for additional reagents acting as electron donor/scavenger for completing the catalytic cycle undermines the practicability of this approach. Herein we demonstrate that photo-induced oxidative C-H functionalization can be catalysed with high product yields under oxygen-free and acceptorless conditions via inner-sphere atom abstraction by binuclear platinum(ii) diphosphite complexes. Both alcohols (51 examples), particularly the aliphatic ones, and saturated N-heterocycles (24 examples) can be efficiently dehydrogenated under light irradiation at room temperature. Regeneration of the photocatalyst by means of reductive elimination of dihydrogen from the in situ formed platinum(iii)-hydride species represents an alternative paradigm to the current approach in photoredox catalysis.
Zhong, Jian-Ji,To, Wai-Pong,Liu, Yungen,Lu, Wei,Che, Chi-Ming
p. 4883 - 4889
(2019/05/16)

Gold(0) catalyzed dehydrogenation of N-heterocycles
Gold nanoclusters are good catalyst precursors for the catalytic dehydrogenation of indolines, tetrahydroquinazolines, and related N-heterocycles. The catalytically active species is presumably Au(0) nanoparticles.
Kumaran, Elumalai,Leong, Weng Kee
supporting information
p. 3958 - 3960
(2018/10/02)

Acceptorless Dehydrogenation of N-Heterocycles and Secondary Alcohols by Ru(II)-NNC Complexes Bearing a Pyrazoyl-indolyl-pyridine Ligand
Ruthenium(II) hydride complexes bearing a pyrazolyl-(2-indol-1-yl)-pyridine ligand were synthesized and structurally characterized by NMR analysis and X-ray single crystal crystallographic determinations. These complexes efficiently catalyzed acceptorless dehydrogenation of N-heterocycles and secondary alcohols, respectively, exhibiting highly catalytic activity with a broad substrate scope. The present work has established a strategy to construct highly active transition metal complex catalysts and provides an atom-economical and environmentally benign protocol for the synthesis of aromatic N-heterocyclic compounds and ketones.
Wang, Qingfu,Chai, Huining,Yu, Zhengkun
p. 584 - 591
(2018/03/08)

A indole compound and its preparation method and application (by machine translation)
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; 0154; 0155

(2018/10/02)

Dehydrogenation of Nitrogen Heterocycles Using Graphene Oxide as a Versatile Metal-Free Catalyst under Air
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
supporting information
p. 2358 - 2363
(2017/07/22)

Organo-Photoredox Catalyzed Oxidative Dehydrogenation of N-Heterocycles
We report here for the first time the catalytic oxidative dehydrogenation of N-heterocycles by a visible-light organo-photoredox catalyst with low catalyst loading (0.1–1 mol %). The reaction proceeds efficiently under base- and additive-free conditions with ambient air at room temperature. The utility of this benign approach is demonstrated by the synthesis of various pharmaceutically relevant N-heteroarenes such as quinoline, quinoxaline, quinazoline, acridine, and indole.
Sahoo, Manoj K.,Jaiswal, Garima,Rana, Jagannath,Balaraman, Ekambaram
supporting information
p. 14167 - 14172
(2017/10/16)

Formation of indoles, dihydroisoquinolines, and dihydroquinolines by ruthenium-catalyzed heterocyclizations
Indoles, dihydroisoquinolines, and dihydroquinolines were efficiently prepared by ruthenium-catalyzed heterocyclizations of aromatic homo- and bis-homopropargyl amines/amides in the presence of an amine/ammonium base-acid pair. These regioselective 5-endo and 6-endo cyclizations most probably occur by nucleophilic trapping of key ruthenium-vinylidene intermediates. Georg Thieme Verlag Stuttgart · New York.
Varela-Fernández, Alejandro,Varela, Jesús A.,Saá, Carlos
p. 3285 - 3295
(2013/01/15)

Chemoselective N-acylation of indoles and oxazolidinones with carbonylazoles
Unique reactivity: In the presence of more reactive amine and alcohol functional groups and of carboxylic acids, the chemoselective N-acylation of indoles (see scheme) and oxazolidinones is achieved by taking advantage of the unique reactivity of carbonylazole acylating agents with catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Copyright
Heller, Stephen T.,Schultz, Erica E.,Sarpong, Richmond
scheme or table
p. 8304 - 8308
(2012/09/08)

Deformylation of indole and azaindole-3-carboxaldehydes using anthranilamide and solid acid heterogeneous catalyst via quinazolinone intermediate
The deformylation of indole and azaindole-3-carboxaldehydes was achieved in the presence of anthranilamide and a solid acid heterogeneous catalyst under reflux conditions in 25-90% yield. The reaction proceeds via quinazolinone intermediate, which undergoes acid catalyzed cleavage to form deformylated product.
Yadav, Rammohan R.,Battini, Narsaiah,Mudududdla, Ramesh,Bharate, Jaideep B.,Muparappu, Nagaraju,Bharate, Sandip B.,Vishwakarma, Ram A.
experimental part
p. 2222 - 2225
(2012/05/20)

Ruthenium-catalyzed cycloisomerization of aromatic homo- and bis-homopropargylic amines/amides: Formation of indoles, dihydroisoquinolines and dihydroquinolines
Ruthenium-catalyzed cycloisomerizations of aromatic homo- and bis-homopropargylic amines/amides efficiently afford indoles, dihydroisoquinolines and dihydroquinolines. These processes were regioselective (5- and 6-endo cyclizations) on using key Ru vinylidene intermediates. The presence of an amine/ammonium base-acid pair increased the rate of cyclization and facilitated the catalytic turnover. Copyright
Varela-Fernandez, Alejandro,Varela, Jesus A.,Saa, Carlos
supporting information; experimental part
p. 1933 - 1937
(2011/10/08)

Highly efficient and facile green approach for one-pot fischer indole synthesis
A simple, efficient and an environmental friendly method have been developed for the synthesis of substituted indole from aryl hydrazines and aldehydes/ ketones with HPA-phosphomolybdic acid as a heterogeneous catalyst. The catalyst is nontoxic and recyclable.
Chaskar, Atul,Deokar, Hrushikesh,Padalkar, Vikas,Phatangare, Kiran,Patil
experimental part
p. 411 - 413
(2010/10/19)

Microwave-accelerated fluorodenitrations and nitrodehalogenations: expeditious routes to labeled PET ligands and fluoropharmaceuticals
Methods for the expeditious fluorination of arenes have been investigated, using readily available fluoride sources. An optimized procedure for microwave-accelerated fluorodenitration has been developed, giving good to excellent yields in less than 10 min, rendering it practical for use in the preparation of F18 labeled ligands for PET imaging. Application of the method in the synthesis of CNS agents is demonstrated, and a practical method for the preparation of substrates is also presented.
LaBeaume, Paul,Placzek, Michael,Daniels, Mathew,Kendrick, Ian,Ng, Patrick,McNeel, Melissa,Afroze, Roushan,Alexander, Abigail,Thomas, Rhiannon,Kallmerten, Amy E.,Jones, Graham B.
experimental part
p. 1906 - 1909
(2010/09/07)

Desulfonylation of indoles and 7-azaindoles using sodium tert-butoxide
A mild method for the desulfonylation of N-indoles and N-azaindoles is described. Deprotection is carried out under basic conditions, using sodium tert-butoxide in dioxane. Several functionalized indoles and 7-azaindoles were efficiently deprotected by this method, which is mild enough to be used to deprotect compounds including functions that are known to be sensitive to acidic or basic conditions.
Chaulet, Charlotte,Croix, Cécile,Basset, Joan,Pujol, Maria-Dolores,Viaud-Massuard, Marie-Claude
experimental part
p. 1481 - 1484
(2010/08/22)

Pd-catalyzed conversion of aryl chlorides, triflates, and nonaflates to nitroaromatics
(Chemical Equation Presented) An efficient Pd catalyst for the transformation of aryl chlorides, triflates, and nonaflates to nitroaromatics has been developed. This reaction proceeds under weakly basic conditions and displays a broad scope and excellent
Fors, Brett P.,Buchwald, Stephen L.
supporting information; experimental part
p. 12898 - 12899
(2009/12/07)

Deprotection of N-BOC compounds
Organic compounds having nitrogen atoms protected with t-butoxycarbonyl are effectively deprotected by heating in a fluorinated alcohol solution.
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Page/Page column 2-3

(2009/08/18)

Deprotection of N-BOC compounds
Organic compounds having nitrogen atoms protected with t-butoxycarbonyl are effectively deprotected by heating in a fluorinated alcohol solution.
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Page/Page column 3; 4-5

(2009/07/10)

A new and efficient one-pot synthesis of indoles
The synthesis of indoles is accomplished in high yields from phenylhydrazines and pyruvic acid using microwave irradiation.
Bratulescu, George
p. 984 - 986
(2008/09/17)

A green N-detosylation of indoles and related heterocycles using phase transfer catalysis
A practical method for the N-detosylation of indoles and related heterocycles with KOH in THF and water in the presence of a phase transfer catalyst is described. Using a nonalcoholic solvent, this method prevents the formation of toxic alkyl p-toluene-sulfonate and consequently eliminates the formation of even traces of N-alkyl byproduct. This green method is particularly useful for indoles bearing electron-withdrawing groups and for azaindoles.
Liu, Yugang,Shen, Lichun,Prashad, Mahavir,Tibbatts, Jessica,Repic, Oljan,Blacklock, Thomas J.
p. 778 - 780
(2013/01/03)

Novel practical deprotection of N-Boc compounds using fluorinated alcohols
The thermolytic deprotection of N-Boc compounds was accomplished using TFE (2,2,2-trifluoroethanol) or HFIP (hexafluoroisopropanol) as solvents. Even though the cleavage of the t-butylcarbamate (Boc) group can be achieved at solvent reflux temperature, the deprotection process was significantly accelerated under microwave-assisted conditions. The practicality of this methodology was demonstrated on alkyl, aryl, and heteroaromatic N-Boc-amines. Copyright Taylor & Francis Group, LLC.
Choy, Jason,Jaime-Figueroa, Saul,Jiang, Laurence,Wagner, Paul
p. 3840 - 3853
(2008/12/23)

Rhodium-catalyzed cycloisomerization: Formation of indoles, benzofurans, and enol lactones
(Chemical Equation Presented) Internal affairs: Indoles, benzofurans, and enol lactones are formed chemoselectively from the rhodium-catalyzed cyclo-isomerization reaction of easily prepared alkynyl aniline substrates (see scheme, cod = cycloocta-1,5-diene, DMF = N,N-dimethylformamide). The reaction may proceed by nucleophilic capture of a vinylidene intermediate. Indoles are formed under mild conditions using low catalyst loadings.
Trost, Barry M.,McClory, Andrew
p. 2074 - 2077
(2008/02/14)

Efficient synthesis of substituted indoles and benzazoles by oxidative aromatization using activated carbon-Molecular oxygen system
Efficient synthesis of substituted indoles was achieved by oxidative aromatization of indolines using activated carbon-molecular oxygen (O2) system. Benzazoles (benzimidazole and benzothiazoles) were also prepared by the reaction of 1,2-phenylenediamine and 2-aminobenzenethiol with formaldehyde in the presence of activated carbon under oxygen atmosphere.
Nomura, Yukiko,Kawashita, Yuka,Hayashi, Masahiko
p. 629 - 635
(2008/09/18)

Deprotection of N-tosylated indoles and related structures using cesium carbonate
A very mild, efficient, and convenient method for deprotection of N-tosylated indoles and related structures by cesium carbonate in THF-MeOH is described.
Bajwa, Joginder S.,Chen, Guang-Pei,Prasad, Kapa,Repi?, Oljan,Blacklock, Thomas J.
p. 6425 - 6427
(2007/10/03)

Mild deprotection of tert-butyl carbamates of NH-heteroarenes under basic conditions
Aqueous methanolic potassium carbonate under reflux has been demonstrated to be a highly effective deprotective agent for the tert -butyl carbamates of indoles, indazoles, carbazole, thiazoloindole, and pyrrole. The method is a mild one and is particularly expeditious for NH-heteroarenes bearing electron-withdrawing groups. Copyright Taylor & Francis Group, LLC.
Chakrabarty, Manas,Kundu, Taraknath,Harigaya, Yoshihiro
p. 2069 - 2077
(2007/10/03)

A mild and efficient method for the mononitration of aromatic compounds by cerium (III) ammonium nitrate in acetic anhydride
A mild and efficient method for the mononitration of aromatic and olefinic compounds is described. This method is especially useful for active substrates.
Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Satsumabayashi, Koko,Horaguchi, Takaaki
p. 497 - 499
(2007/10/03)

A mild and efficient dehydrogenation of indolines
A new mild and efficient dehydrogenation of indolines to indoles has been developed. For the dehydrogenation trichloroisocyanuric acid is used in combination with DBU. After work-up with sodium hydrogen sulfite it was possible to obtain indole in an almost quantitative yield. The new method is also suitable for indolines bearing electron withdrawing or electron donating groups. Under the reaction conditions no ring chlorination was observed.
Tilstam, Ulf,Harre, Michael,Heckrodt, Thilo,Weinmann, Hilmar
p. 5385 - 5387
(2007/10/03)

Traceless linking of indoles: General methodology and application to solid phase supported Mannich and Stille reactions
Transacetalization reaction of the diethoxymethyl (DEM) protected indoles 2a,b,d,e with the polymer bound glycerol derivative 3 resulted in formation of the immobilized indoles 4a,b,d,e. Selective indole- functionalizations as well as quantitative and traceless cleavage could be demonstrated.
Kraxner, Johannes,Arlt, Michael,Gmeiner, Peter
p. 125 - 127
(2007/10/03)

Substituent Effects on the Spectral, Acid-Base, and Redox Properties of Indolyl Radicals: A Pulse Radiolysis Study
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
p. 6674 - 6679
(2007/10/02)

DEHYDROGENATION OF CERTAIN INDOLINE DERIVATIVES INTO INDOLES
The dehydrogenation was studied of certain acceptor indoline derivatives in nitrobenzene, in the presence of cadmium, sodium, and potassium carbonates.A method has been proposed for a mild dehydrogenation of certain acceptor groups containing indoline derivatives in nitrobenzene, in the presence of potassium carbonate.
Vorob'eva, S. L.,Buyanov, V. N.,Suvorov, N. N.
p. 506 - 507
(2007/10/02)

SIMPLE SYNTHESES OF 1,3,4,5-TETRAHYDROPYRROLOQUINOLINE AND 5-HYDROXY-4-NITROINDOLE (SYNTHETIC STUDY FOR INDOLES HAVING A NITROGEN CONTAINING FUNCTIONAL GROUP AT THE 4-POSITION)
A simple four (or three) step synthesis method for 1,3,4,5-tetrahydropyrroloquinoline (6) from indole-3-carboxaldehyde (9) is developed.A single step preparation of 5-hydroxy-4-nitroindole (8) by the oxidation of 4-aminoindole (16) is also reported.
Hamabuchi, Shin,Hamada, Hirokazu,Hironaka, Akiko,Somei, Masanori
p. 443 - 448
(2007/10/02)

THE OXIDATION OF AROMATIC AMINES IN THE PRESENCE OF "ELECTRON-RICH" AROMATIC SYSTEMS
The oxidation of aromatic amines to the corresponding nitro substituents is performed under mild, nonacidic conditions in the presence of highly nucleophilic aromatic systems such as indoles and furans.
Zabrowsky, Daniel L.,Moormann, Alan E.,Beck, Kenneth R.
p. 4501 - 4504
(2007/10/02)

Synthesis of Indole Derivatives from 2-Bromoanilines by a Palladium-assisted Reaction
In the presence of palladium(II) acetate, 2-bromoanilines readily react with enamines such as N-vinylpyrrolidone or α-piperidinostyrene to produce indole derivatives.
Kasahara, Akira,Izumi, Taeko,Kikuchi, Tokio,Xiao-ping Lin
p. 1555 - 1556
(2007/10/02)

HETEROGENEOUS-CATALYTIC E. FISCHER REACTION XIV. EFFECT OF ELECTRONIC FACTORS IN THE HETEROGENEOUS-CATALYTIC E. FISCHER REACTION
The effect of electronic factors on the heterogeneous-catalytic E.Fischer reaction was studied for the case of methoxy- and nitro-substituted arylhydrazones.It was shown that the presence of the methoxy groups in all probability increases the basicity of the respective hydrazone and facilitates adsorption of the active centers of the catalyst.In this case indoles are obtained with high yields.The presence of nitro groups hinder the adsorption of the hydrazone on the catalyst and as a result leads to a decrease in the yield of indole.
Suvorov, N. N.,Shkil'kova, V. N.,Podkhalyuzina, N. Ya.
p. 2117 - 2120
(2007/10/02)