- 2-Substituted 3-aryl- and 3-heteroarylindoles by the palladium-catalyzed reaction of o-trifluoroacetanilides with aryl bromides and triflates
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The palladium-catalyzed reaction of aryl and heteroaryl bromides and triflates with o-alkynyltrifluoroacetanilides affords 2-substituted 3-aryl- and heteroarylindoles usually in excellent yield. The procedure can be applied to the synthesis of 2-substituted indole-3-carboxaldehydes.
- Cacchi, Sandro,Fabrizi, Giancarlo,Lamba, Doriano,Marinelli, Fabio,Parisi, Luca M.
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- Dissecting the Electronic Contribution to the Regioselectivity of the Larock Heteroannulation Reaction in the Oxidative Addition and Carbopalladation Steps
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Substituted 2-iodoaniline derivatives were prepared and utilized as reactants, along with asymmetric diarylacetylenes, to synthesize a series of 6-substituted-2,3-diarylindole derivatives via the Larock heteroannulation reaction. Electron-donating substituents on the 2-iodoaniline derivatives retarded the reaction, while electron-withdrawing substituents provided a complete conversion to the indole products. In addition, the electronic properties of the substituted 2-iodoaniline reactants displayed no influence toward regioselectivity. On the contrary, the electronic effect from unsymmetrical diarylacetylenes significantly influenced the regiochemical outcome of the reaction. Density functional theory calculations of the oxidative addition and carbopalladation steps revealed the electronic influences of the substituted 2-iodoaniline derivatives toward the overall rate of the reaction. In contrast, the electronic properties of the asymmetric diarylacetylene remained the critical product-determining factor of regioselectivity.
- Chuawong, Pitak,Gable, Kevin P.,Yiamsawat, Kanyapat
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p. 1218 - 1229
(2022/01/27)
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- Selective Synthesis of N-Unsubstituted and N-Arylindoles by the Reaction of Arynes with Azirines
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The transition-metal-free and temperature-dependent highly selective reaction of arynes with 2H-azirines allowing the synthesis of either N-unsubstituted or N-arylindoles has been developed. At 60 °C, arynes generated from 2-(trimethylsilyl)aryl triflates smoothly insert into 2H-azirines to form 2,3-diarylindoles with high selectivity. Interestingly, when the reaction was performed at -10 °C, the selectivity was switched to the formation of 1,2,3-triarylindoles in good yields.
- Thangaraj, Manikandan,Bhojgude, Sachin Suresh,Jain, Shailja,Gonnade, Rajesh G.,Biju, Akkattu T.
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p. 8604 - 8611
(2016/09/28)
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- A synthetic 2,3-diarylindole induces cell death via apoptosis and autophagy in A549 lung cancer cells
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A series of 2,3-diarylindoles were synthesized via the Larock heteroannulation, and evaluated for their anticancer activity against A549 lung cancer cells. The most potent compound, PCNT13 with IC50 = 5.17 μM, caused the induction of two modes of programmed cell death, apoptosis and autophagy.
- Rukkijakan, Thanya,Ngiwsara, Lukana,Lirdprapamongkol, Kriengsak,Svasti, Jisnuson,Phetrak, Nared,Chuawong, Pitak
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p. 2119 - 2123
(2016/04/20)
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- Rhodium(III)-Catalyzed Redox-Neutral C-H Annulation of Arylnitrones and Alkynes for the Synthesis of Indole Derivatives
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By using a nitrone as the oxidizing directing group, a mild, practical and efficient rhodium(III)-catalyzed C-H functionalization for the synthesis of indole derivatives has been developed. This reaction obviates the need for an external oxidant and shows good functional group tolerance. The employment of a sterically hindered Mes group on the carbon center of the nitrone is crucial to produce indoles in high yield.
- Zhou, Zhi,Liu, Guixia,Chen, Yan,Lu, Xiyan
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supporting information
p. 2944 - 2950
(2015/09/28)
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- URAZOLE COMPOUNDS
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The present invention relates to a compound of formula (I) or a stereoisomer, enantiomer, racemic, or tautomer thereof, (I) wherein R1, R2, R3, R4, R5, R6, R7, L1 and Q1 have the meaning defined in the claims and the description. The present invention also relates to a process for the preparation of the compound of formula (I). The present invention also relates to the use of a compound of formula (I) as an in situ precursor of a triazolinedione reagent for the functionalization of enes, dienes, aryl and heteroaryl systems via the ene reactions, Diels-Alder reactions, and electrophilic aromatic substitution reactions of said reagent. The present invention also relates to the use of a compound of formula (I) in polymers, membranes, adhesives, foams, sealants, molded articles, films, extruded articles, fibers, elastomers, polymer based additives, pharmaceutical and biomedical products, varnishes, paints, coatings, inks, composite material, organic LEDs, organic semiconductors, conducting organic polymers, or 3D printed articles. The present invention also relates to article comprising said compound of formula (I) and to a process for reshaping and/or repairing said article.
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- Regioselectivity of Larock heteroannulation: A contribution from electronic properties of diarylacetylenes
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A series of 2,3-diarylindoles were synthesized from 2-iodoaniline and unsymmetrical diarylacetylenes using the Larock heteroannulation. Diarylacetylenes bearing electron-withdrawing substituents lead to 2,3-diarylindoles with substituted phenyl moieties at the 2-position as major products, while those with electron-donating groups preferably yield indole products with substituted phenyl moieties at the 3-position. The regioisomeric product ratios exhibit a clear correlation with Hammett σp values. DFT calculations reveal the origin of this effect, displaying smaller activation energy barriers for those pathways leading to the major regioisomer.
- Phetrak, Nared,Rukkijakan, Thanya,Sirijaraensre, Jakkapan,Prabpai, Samran,Kongsaeree, Palangpon,Klinchan, Chayada,Chuawong, Pitak
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p. 12703 - 12709
(2014/01/17)
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- 2,3-disubstituted indoles via palladium-catalyzed reaction of 2-alkynyltrifluoroacetanilides with arenediazonium tetrafluoroborates
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(Figure Presented) A novel palladium-catalyzed synthesis of free N-H 2,3-disubstituted indoles from arenediazonium tetrafluoroborates and 2-alkynyltrifluoroacetanilides is presented. The reaction tolerates a variety of useful substituents both in the starting alkyne and the arenediazonium salt, including bromo and chloro substituents, nitro, cyano, keto, ester, and ether groups, as well as ortho substituents such as methoxy and methyl groups.
- Cacchi, Sandro,Fabrizi, Giancarlo,Goggiamani, Antonella,Perboni, Alcide,Sferrazza, Alessio,Stabile, Paolo
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supporting information; experimental part
p. 3279 - 3281
(2010/10/02)
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- Perfluoro-tagged, phosphine-free palladium nanoparticles supported on silica gel: Application to alkynylation of aryl halides, Suzuki-Miyaura cross-coupling, and Heck reactions under aerobic conditions
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The utilization of perfluoro-tagged palladium nanoparticles immobilized on fluorous silica gel through fluorous-fluorous interactions (Pd np-A/FSG) or through covalent bonding to silica gel (Pd np-B) in the alkynylation of aryl halides, in the Suzuki-Miyaura cross-coupling, as well as in the Heck reaction between methyl acrylate and aryl iodides is described. The reactions are carried out under aerobic and phosphine-free conditions with excellent to quantitative product yields in each case. The catalysts are easily recovered and reused several times without significant loss of activity. The alkynylation of aryl halides (under copper-free conditions) and the Suzuki-Miyaura cross-coupling are carried out in water. The Heck reaction of methyl acrylate with aryl iodides is best performed in MeCN. The utilization of Pdnp-B in the synthesis of 2,3-disubstituted indoles from 2-(alkynyl)trifluoroacetanilides and aryl halides is also reported.
- Bernini, Roberta,Cacchi, Sandro,Fabrizi, Giancarlo,Forte, Giovanni,Petrucci, Francesco,Prastaro, Alessandro,Niembro, Sandra,Shafir, Alexandr,Vallribera, Adelina
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supporting information; experimental part
p. 150 - 158
(2010/05/18)
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- First heterogeneously palladium-catalysed fully selective C3-arylation of free NH-indoles
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A simple heterogeneously palladium-catalysed procedure for the selective C3-arylation of indoles is reported. Under relatively standard reaction conditions (Pd-catalyst, K2CO3, dioxane, reflux), using only 1 mol % [Pd(NH3)4]/NaY as the catalyst, indoles substituted or not at position 2 gave up to 92% conversion (i.e., 85% isolated yield) towards the expected C3-arylated indole.
- Cusati, Giuseppe,Djakovitch, Laurent
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p. 2499 - 2502
(2008/09/19)
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- Heterogeneous palladium catalysts applied to the synthesis of 2- and 2,3-functionalised indoles
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Heterogeneous palladium catalysts ([Pd(NH3)4] 2+/NaY and [Pd]/SBA-15) were applied to the synthesis of 2-functionalised indoles, giving generally high conversions and selectivities (>89% yield) using only 1 mol % [Pd]-catalyst under standard reaction conditions (polar solvent, 80°C). For the synthesis of 2,3-functionalised indoles by cross-coupling arylation, the [Pd]/SBA-15 catalyst was found to be particularly interesting, producing the expected compound with =35% yield after 12 days of reaction, which is comparable to the homogeneous catalyst, Pd(OAc)2 (= 48% yield). In the course of the study, the dual reactivity of the indole nucleus was demonstrated: aryl bromides gave clean C-C coupling while aryl iodides led to a clean C-N coupling.
- Djakovitch, Laurent,Dufaud, Veronique,Zaidi, Rabah
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p. 715 - 724
(2007/10/03)
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- A practical mild, one-pot, regiospecific synthesis of 2,3-disubstituted indoles via consecutive Sonogashira and Cacchi reactions
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A practical one-pot, regiospecific three-component process for the synthesis of 2,3-disubstituted indoles was developed via consecutive Pd-catalyzed Sonogashira coupling, amidopalladation, and reductive elimination.
- Lu, Bruce Z.,Zhao, Wenyi,Wei, Han-Xun,Dufour, Marine,Farina, Vittorio,Senanayake, Chris H.
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p. 3271 - 3274
(2007/10/03)
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- Preparation of indoles from o-alkynyltrifluoroacetanilides through the aminopalladation-reductive elimination process
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The functionalized pyrrole nucleus contained in the indole system has been assembled via the palladium-catalyzed reaction of o-alkynyltrifluoroacetanilides with organic halides/triflates or allyl carbonates. In the presence of carbon monoxide, a three-com
- Cacchi, Sandro,Fabrizi, Giancarlo,Parisi, Luca M.
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p. 1889 - 1894
(2007/10/03)
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