120-72-9Relevant articles and documents
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Suvorov et al.
, (1970)
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A BN Aromatic Ring Strategy for Tunable Hydroxy Content in Polystyrene
van de Wouw, Heidi L.,Lee, Jae Young,Awuyah, Elorm C.,Klausen, Rebekka S.
, p. 1673 - 1677 (2018)
BN 2-vinylnaphthalene, a BN aromatic vinyl monomer, is copolymerized with styrene under free radical conditions. Oxidation yields styrene–vinyl alcohol (SVA) statistical copolymers with tunable hydroxy group content. Comprehensive spectroscopic investigation provides proof of structure. Physical properties that vary systematically with hydroxy content include solubility and glass transition temperature. BN aromatic polymers represent a platform for the preparation of diverse functional polymeric architectures via the remarkable reaction chemistry of C?B bonds.
Origin of Stability and Inhibition of Cooperative Alkyne Hydrofunctionalization Catalysts
Chapple, Devon E.,Boyle, Paul D.,Blacquiere, Johanna M.
, p. 3789 - 3800 (2021)
New entries to the [Ru(Cp/Cp*)(PR2NR′2)(MeCN)]PF6 catalyst family were synthesized, including a Cp complex (R = Cy; R′ = Ph) and two Cp* complexes (R = Cy, Ph; R′ = Ph). These and other derivatives were used for the intramolecular hydroamination of 2-ethynylaniline to elucidate trends in catalytic lifetime and rate. The readily accessible [Ru(Cp)(PCy2NPh2)(MeCN)]PF6 derivative showed comparable lifetime to [Ru(Cp)(Pt?Bu2NPh2)(MeCN)]PF6, the previous optimal catalyst. Donor-free ‘active’ catalysts, [Ru(Cp/Cp*)(PCy2NPh2)]PF6, were prepared and their thermal stability was assessed. The relatively high stability of the Cp derivative was explained by the capacity of the PCy2NPh2 ligand to coordinate in a κ3-(P,P,Ar) mode, which protects the low-coordinate species. This coordination mode is inaccessible with the Cp* derivative. Additionally, [Ru(Cp*)(PCy2NPh2)]PF6 readily activated the C?Cl bond of the solvent dichloromethane. Variable time normalization analysis (VTNA) revealed that the indole product inhibited the catalyst [Ru(Cp)(PCy2NPh2)(MeCN)]PF6, which slowed catalytic rates.
Group VI metal-promoted endo-azacyclizations via alkyne-derived metal vinylidene carbenes
McDonald, Frank E.,Chatterjee, Arnab K.
, p. 7687 - 7690 (1997)
The molybdenum-promoted cycloisomerization of terminal alkynes tethered to nitrogen nucleophiles is described. Reaction of N-carbamoyl alkynylamines with (Et3N)Mo(CO)5 affords cyclic enecarbamates. Similarly, cyclization of 2-ethynylaniline gives the isomeric indole heterocycle, although N-3- butynylaniline affords the cyclic metal azacarbene product.
Ruthenium-catalyzed intramolecular hydroamination of aminoalkynes
Kondo, Teruyuki,Okada, Takumi,Suzuki, Toshiaki,Mitsudo, Take-Aki
, p. 149 - 154 (2001)
Low-valent ruthenium complexes with a π-acidic ligand, such as Ru(η6-cot)(dmfm)2 [cot=1,3,5-cyclooctatriene, dmfm=dimethyl fumarate] and Ru3(CO)12, showed high catalytic activity for the intramolecular hydroamination of aminoalkynes. The reaction is highly regioselective, in which a nitrogen atom is selectively attached to an internal carbon of alkynes to give five-, six-, and seven-membered nitrogen heterocycles as well as indoles in good to high yields.
Protonated carbonic acid and reactive intermediates in the acidic decarboxylation of indolecarboxylic acids
Vandersteen, Adelle A.,Mundle, Scott O.C.,Kluger, Ronald
, p. 6505 - 6509 (2012)
Elucidation of the mechanism for decarboxylation of indolecarboxylic acids over a wide range of solution acidity reveals the importance of protonated carbonic acid (PCA) as a reaction intermediate. In concentrated acid, the initial addition of water to the carboxyl group of the indolecarboxylic acid leads to a hydrated species that is capable of releasing PCA upon rate-determining carbon-carbon bond cleavage. The overall process is catalytic in water and acid, implicating PCA as a potential carboxylating reagent in the microscopic reverse reaction.
DDQ as an electrocatalyst for amine dehydrogenation, a model system for virtual hydrogen storage
Luca, Oana R.,Wang, Ting,Konezny, Steven J.,Batista, Victor S.,Crabtree, Robert H.
, p. 998 - 999 (2011)
2,3-Dichloro-5,6-dicyanobenzoquinone (DDQ) is an electrochemical oxidation catalyst for a secondary amine, a model system for virtual hydrogen storage by removal of a hydrogen equivalent from an amine; a computational study provides mechanistic information. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011.
Thermodynamics and kinetics of indole oligomerization: Preliminary results in aqueous sulfuric acid
Quartarone,Ronchin,Tortato,Vavasori
, p. 107 - 112 (2009)
Reaction rates and equilibrium constants of indole dimerization and trimerization in aqueous sulfuric acid at 298 K are reported. The equilibrium of oligomerization is attained in about 4-5 h, and formation of oligomers with more than three monomeric unit
Nucleophilic dimerization of indoline under oxidative conditions
Kovalev, Igor S.,Kopchuk, Dmitry S.,Zyryanov, Grigory V.,Rusinov, Vladimir L.,Chupakhin, Oleg N.
, p. 40 - 41 (2014)
Oxidation of indoline with 30% hydrogen peroxide in methanol in the presence of sodium tungstate affords the dimeric 3-oxo-1'H,3H- 2,3'-biindole-1-oxide.
Simultaneous chemosensing of tryptophan and the bacterial signal molecule indole by boron doped diamond electrode
Buzid, Alyah,Reen, F. Jerry,O'Gara, Fergal,McGlacken, Gerard P.,Glennon, Jeremy D.,Luong, John H.T.
, p. 845 - 852 (2018)
A simple and robust chemosensing approach using a boron-doped diamond (BDD) electrode has been developed and applied to analyze tryptophan (TRP) and indole during the growth of Escherichia coli in a complex growth medium. The bacterial enzyme tryptophanase catalyzes TRP to indole, an emerging signaling molecule. The process can now be monitored using electrochemistry, in a method far beyond the traditional identification protocols. Electroanalysis in a non-aqueous medium comprising acetonitrile (ACN) and tetrabutylammonium hexafluorophosphate (TBAH) is capable of separating the oxidation peak of TRP from that of indole. Mechanisms are postulated for the electrochemical oxidation of indole and TRP in ACN chosen because of its wider potential range, proton acceptor property, and solubilization of analytes. The electrochemical oxidation of TRP involves the elimination of two electrons. With a detection limit of 0.5 μM for both indole and TRP, this chemosensing approach is sufficient to monitor the level of these two biomolecules during the bacterial growth period.
Evolution of the indole alkaloid biosynthesis in the genus Hordeum: Distribution of gramine and DIBOA and isolation of the benzoxazinoid biosynthesis genes from Hordeum lechleri
Gruen, Sebastian,Frey, Monika,Gierl, Alfons
, p. 1264 - 1272 (2005)
Two indole alkaloids with defense related functions are synthesized in the genus Hordeum of the Triticeae. Gramine (3(dimethyl-amino-methyl)-indole) is found in H. spontaneum and in some varieties of H. vulgare, the benzoxazinoid 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) is detected in H. roshevitzii, H. brachyantherum, H. flexuosum, H. lechleri. Biosynthesis of DIBOA and of gramine was found to be mutually exclusive in wild Hordeum species, indicating that there was selection against simultaneous expression of both pathways during evolution. The full set of genes required for DIBOA biosynthesis in H.lechleri was isolated and the respective enzyme functions were analyzed by heterologous expression. The cytochrome P450 genes Bx2-Bx5 demonstrate a monophyletic origin for H. lechleri, Triticum aestivum and Zea mays. HlBx2-HlBx5 share highest homology to the orthologous genes of T. aestivum. In contrast, the branch point enzyme of the DIBOA pathway, the indole-3-glycerol phosphate lyase BX1, might have evolved independently in H. lechleri. In all Hordeum species that synthesize DIBOA, DNA sequences homologous to Bx genes are found. In contrast, these sequences are not detectable in the genomes of H. vulgare and H. spontaneum that do not synthesize benzoxazinoids.
Reaction pathway in the vapour-phase synthesis of indole and alkylindoles
Campanati,Franceschini,Piccolo,Vaccari
, p. 1 - 9 (2005)
The vapour-phase synthesis of indole and its derivatives from aniline or alkylanilines and ethylene glycol or other diols was investigated with the use of a novel ZrO2/SiO2 (5:95 w/w) catalyst to check the applicability of this synthesis to a wide number of alkylindoles. During feeding with alkylaniline, the above catalyst showed catalytic results better than those reported in the literature, and a very good regenerability. In particular, with ethylene glycol, the best yields in the corresponding indoles were obtained when a C2-C3 alkyl chain was located in the ortho position to the amino group. The differences in reactivity between aniline and alkylaniline were significantly reduced when the length of the diol chain was increased and eliminated with 2,3-butanediol. On the basis of the above data and those collected sharing the synthesis in single steps, a possible overall reaction pathway was proposed to design a better tailor-made catalyst. It was also indicated that the formation of heavy compounds, which are able to deactivate the catalyst, were not derived from the reagents or the following reactions on the indole formed, but might be mainly attributed to the polycondensation of an aldehyde intermediate.
Radicals and radical ions derived from indole, indole-3-carbinol and diindolylmethane
Bloch-Mechkour, Anna,Bally, Thomas,Sikora, Adam,Michalski, Radoslaw,Marcinek, Andrzej,Gebicki, Jerzy
, p. 6787 - 6794 (2010)
The primary products, i.e., the radical cations and radicals obtained on oxidation of the glucobrassicin metabolites (and dietary supplements), indole-3-carbinol (I3C) and diindolylmethane (DIM), and those from parent indole (I) are characterized in an ionic liquid and in Ar matrices. The radical cations of I and I3C are stable toward (photo)deprotonation under these conditions, but the resulting radicals can be generated by UV-photolysis of the neutral precursors. Two types of radicals, obtained by loss of hydrogen from N- and C-atoms, respectively, are found for I3C and DIM.
Transition metal-free regioselective C-3 amidation of indoles with N-fluorobenzenesulfonimide
Liu, Hai-Hong,Wang, Yi,Deng, Guojun,Yang, Luo
, p. 3369 - 3374 (2013)
A direct transition metal-free regioselective C-3 amidation of indoles has been developed with the commercially available N-fluorobenzenesulfonimide (NFSI) as the amino source under external oxidant-free conditions. This amidation requires only a catalytic amount of base and exhibits excellent functional group tolerance and regioselectivity. The C-3 regioselectivity was proposed to realize by a free radical mechanism. Copyright
Striking effects of a titania support on the low-temperature activities of Ir catalysts for the dehydrogenative synthesis of benzimidazole and indole
Fukutake, Tatsuhiro,Wada, Kenji,Liu, Gang Chuan,Hosokawa, Saburo,Feng, Qi
, p. 235 - 240 (2018)
The crystalline structure of titania supports for iridium catalysts markedly affected their low-temperature activity for the dehydrogenative synthesis of N-containing heteroaromatics, namely benzimidazole and indole. While solid iridium catalysts supported on anatase showed moderate to poor activity for the synthesis of 2-phenylbenzimidazole (3) from o-phenylenediamine (1) and benzyl alcohol (2) at 100 °C, the reaction in the presence of rutile-supported catalysts proceeded smoothly to give 3 in high yields of up to 88%. Similar results were observed for the dehydrogenative conversion of 2-(2-aminophenyl)-ethanol (4) to indole (5). The reaction at 100 °C for 18 h in the presence of 1.0 mol% iridium on rutile gave 5 in a yield of 73%, while the use of anatase-supported catalysts resulted in significantly lower yields. TEM analysis showed the formation of small (ca. 2 nm in diameter), homogeneously-dispersed iridium nanoparticles on rutiles, while the inhomogeneous loading of iridium species was observed on anatase supports. CO pulse experiments revealed that there is a strong correlation between CO uptake by iridium nanoparticles and the activities at 100 °C. These results suggest that the predominant formation of small, well-reduced iridium nanoparticles is one major reason for the excellent activities of rutile-supported catalysts at low temperatures.
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Ermolenko et al.
, (1978)
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OXIDATIVE DECARBOXYLATION OF CYCLIC AMINO ACIDS AND DEHYDROGENATION OF CYCLIC SECONDARY AMINES WITH IODOSOBENZENE
Ochiai, Masahito,Inenaga, Minako,Nagao, Yoshimitsu,Moriarty, Robert M.,Vaid, Radhe K.,Duncan, Michael P.
, p. 6917 - 6920 (1988)
Cyclic amino acids L-proline, pipecolinic acid and L-2-pyrrolidinone-5-carboxylic acid undergo oxidative decarboxylation with iodosobenzene in various solvents (including water) to yield the lactam and imide in the latter case.The reaction proceeds via initial imine formation.
SUBSTITUTION NUCLEOPHILE RADICALAIRE (SRN1) INDUITE PAR VOIE ELECTROCHIMIQUE
Boujlel, K.,Simonet, J.,Roussi, G.,Beugelmans, R.
, p. 173 - 176 (1982)
The electrochemical method is used for initiate a radical nucleophilic substitution leading to the synthesis of indoles.
Pyrylenes: A New Class of Tunable, Redox-Switchable, Photoexcitable Pyrylium-Carbene Hybrids with Three Stable Redox-States
Antoni, Patrick W.,Hansmann, Max M.
, p. 14823 - 14835 (2018)
A new synthetic and modular access to a large family of redox-switchable molecules based upon the combination of pyrylium salts and carbenes is presented. The redox-properties of this new molecule class correlate very well with the π-accepting properties of the corresponding carbenes. While the pyrylium moiety acts as a chromophore, the carbene moiety can tune the redox-properties and stabilize the corresponding radicals. This leads to the isolation of the first monomeric pyranyl-radical in the solid-state. The three stable oxidation states could be cleanly accessed by chemical oxidation, characterized by NMR, EPR, UV-vis, and X-ray diffraction and supported by (TD)-DFT-calculations. The new hybrid class can be utilized as an electrochemically triggered switch and as a powerful photoexcited reductant. Importantly, the pyrylenes can be used as novel photocatalysts for the reductive activation of aryl halides and sulfonamides by consecutive visible light induced electron transfer processes.
A NEW DEHYDROGENATION REACTION OF INDOLINES TO INDOLES VIA AZASULFONIUM SALTS
Kikugawa, Yasuo,Kawase, Masami
, p. 445 - 446 (1981)
Indolines (1) have been converted to the corresponding azasulfonium salts (2) and the subsequent intramolecular base catalyzed abstraction of the hydrogen at C-2 gave indoles (4) in good yields.
Kinetics and mechanism of the basic hydrolysis of indomethacin and related compounds: A reevaluation
Cipiciani,Ebert,Linda,Rubessa,Savelli
, p. 1075 - 1076 (1983)
The kinetics of the hydrolysis of indomethacin and related compounds were studied in an alkaline medium at 25°. The pseudo-first-order rate constants were evaluated from log absorbance versus time plots in the ultraviolet. These compounds showed a second-order rate constant at low concentrations of hydroxide ion and a first-order rate constant at higher concentrations of hydroxide ion.
Improved indole syntheses from anilines and vicinal diols by cooperative catalysis of ruthenium complex and acid
Zhang, Min,Xie, Feng,Wang, Xiaoting,Yan, Fengxia,Wang, Ting,Chen, Mengmeng,Ding, Yuqiang
, p. 6022 - 6029 (2013)
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.
Efficient nickel-mediated intramolecular amination of aryl chlorides
Omar-Amrani, Rafik,Thomas, Antoine,Brenner, Eric,Schneider, Raphael,Fort, Yves
, p. 2311 - 2314 (2003)
(Matrix presented) The use of an in situ generated Ni(0) catalyst associated with 2,2′-bipyridine or N,N′ -bis(2,6-diisopropylphenyl)dihydroimidazol-2-ylidene (SIPr) as a ligand and NaO-t-Bu as the base for the intramolecular coupling of aryl chlorides with amines is described. The procedure has been applied to the formation of five-, six-, and seven-membered rings.
A preparative synthesis of indole by dehydrogenation of 4,5,6,7-tetrahydroindole over catalysts with a low palladium content
Ryashentseva, M. A.
, p. 1756 - 1757 (1993)
Catalysts containing 0.15 - 0.5 percent of Pd are highly active and selective in the dehydrogenation of 4,5,6,7-tetrahydroindole to indole when γ-Al2O3 or Sibunite are used as supports. - Keywords: Pd-containing catalysts, tetrahydroindole, indole, dehydrogenation.
Ordered Porous Nitrogen-Doped Carbon Matrix with Atomically Dispersed Cobalt Sites as an Efficient Catalyst for Dehydrogenation and Transfer Hydrogenation of N-Heterocycles
Han, Yunhu,Wang, Ziyun,Xu, Ruirui,Zhang, Wei,Chen, Wenxing,Zheng, Lirong,Zhang, Jian,Luo, Jun,Wu, Konglin,Zhu, Youqi,Chen, Chen,Peng, Qing,Liu, Qiang,Hu,Wang, Dingsheng,Li, Yadong
, p. 11262 - 11266 (2018)
Single-atom catalysts (SACs) have been explored widely as potential substitutes for homogeneous catalysts. Isolated cobalt single-atom sites were stabilized on an ordered porous nitrogen-doped carbon matrix (ISAS-Co/OPNC). ISAS-Co/OPNC is a highly efficient catalyst for acceptorless dehydrogenation of N-heterocycles to release H2. ISAS-Co/OPNC also exhibits excellent catalytic activity for the reverse transfer hydrogenation (or hydrogenation) of N-heterocycles to store H2, using formic acid or external hydrogen as a hydrogen source. The catalytic performance of ISAS-Co/OPNC in both reactions surpasses previously reported homogeneous and heterogeneous precious-metal catalysts. The reaction mechanisms are systematically investigated using first-principles calculations and it is suggested that the Eley–Rideal mechanism is dominant.
A biomass-derived N-doped porous carbon catalyst for the aerobic dehydrogenation of nitrogen heterocycles
Cui, Fu-Jun,Guo, Fu-Hu,Liu, Jing-Jiang,Liu, Xiao-Yu,Quan, Zheng-Jun,Ullah, Arif,Wang, Xi-Cun,Zhu, Ji-Hua
supporting information, p. 1791 - 1799 (2022/01/31)
N-doped porous carbon (NC) was synthesized from sugar cane bagasse, which is a sustainable and widely available biomass waste. The preferred NC sample had a well-developed porous structure, a graphene-like surface morphology and different N species. More
Chemoselective hydrosilylation of carboxylic acids using a phosphine-free ruthenium complex and phenylsilane
Abhilash, Vishwanathan,Gadakh, Amol V.,Ganesh, Sambasivam,Hegde, Shivaprasad N.,Jacob, Anand,Karthik, C. S.,Lamees, Thundianandi,Mathivanan, Namachivayam,Sathiyanarayanan, Arumugam Murugan
supporting information, (2022/03/01)
A highly chemoselective hydrosilylation of carboxylic acids was achieved using a bench-stable, phosphine-free Ru-complex tethered with hemi-labile thiophene ligands as the catalyst, employing phenylsilane as the reducing agent. The methodology was further elaborated towards the one-pot synthesis of indole and benzoxazine via tandem reduction/cyclization of acid and nitro group.
Synthesis of Non-Terminal Alkenyl Ethers, Alkenyl Sulfides, and N-Vinylazoles from Arylaldehydes or Diarylketones, DMSO and O, S, N-Nucleophiles
Nie, Zhiwen,Lv, Huifang,Yang, Tonglin,Su, Miaodong,Luo, Weiping,Liu, Qiang,Guo, Cancheng
supporting information, p. 1473 - 1480 (2022/04/03)
A transition-metal-free protocol for the synthesis of non-terminal alkenyl ethers, alkenyl sulfides, and N-vinylazoles from arylaldehydes or diarylketones, DMSO and O, S, N-nucleophiles has been reported. In this protocol, 24 examples of non-terminal alkenyl ethers and 28 examples of non-terminal alkenyl sulfides in 72–95% yields have been synthesized within 5 min. Moreover, 27 examples of non-terminal N-vinylazoles with 57–88% yields have also been synthesized within 2 hours. The preliminary mechanism investigations revealed that arylaldehydes or diarylketones offered a carbon atom, DMSO provided a methine and O, S, N-nucleophiles contributed one X atom for constructing C=C?X structure. (Figure presented.).
