- Merging Visible Light Photocatalysis and l-/d-Proline Catalysis: Direct Asymmetric Oxidative Dearomatization of 2-Arylindoles to Access C2-Quaternary Indolin-3-ones
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A mild and effective method for asymmetric synthesis of C2-quaternary indolin-3-ones directly from 2-arylindoles by combining visible light photocatalysis and organocatalysis is described. In this reaction, 2-substituted indoles undergo photocatalyzed oxidative dearomatization, followed by an organocatalyzed asymmetric Mannich reaction with ketones or aldehydes. Products with opposite configurations are easily obtained in satisfactory yields with excellent enantio- A nd diastereoselectivity by employing readily available l- A nd d-proline as chiral organocatalysts.
- Dong, Chun-Lin,Ding, Xuan,Huang, Lan-Qian,He, Yan-Hong,Guan, Zhi
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supporting information
p. 1076 - 1080
(2020/02/15)
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- Highly enantioselective electrosynthesis of C2-quaternary indolin-3-ones
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A highly enantioselective and direct synthesis of C2-quaternary indolin-3-ones from 2-arylindoles by combining electrochemistry and organocatalysis is described. Excellent enantioselectivities (up to 99% ee) and diastereoselectivities (>20 : 1) can be obtained through anodic oxidation in combination with asymmetric proline-catalyzed alkylation in an undivided cell under constant-current conditions.
- Chen, Yu-Jue,Chen, Yuan,Ding, Xuan,Guan, Zhi,He, Yan-Hong,Lu, Fo-Yun
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supporting information
p. 623 - 626
(2020/01/28)
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- Palladium-catalyzed direct C2-arylation of free (N–H) indoles via norbornene-mediated regioselective C–H activation
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A palladium-catalyzed direct C2-arylation reaction of free (N–H) indoles has been developed. This reaction relies on a norbornene-mediated C–H activation process on the indole ring, which features high regioselectivity and excellent functional group tolerance.
- Gao, Yadong,Zhu, Wangying,Yin, Long,Dong, Bo,Fu, Jingjing,Ye, Zhiwen,Xue, Fengtian,Jiang, Chao
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supporting information
p. 2213 - 2216
(2017/05/16)
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- Access to 2-Arylindoles via Decarboxylative C?C Coupling in Aqueous Medium and to Heteroaryl Carboxylates under Base-Free Conditions using Diaryliodonium Salts
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Easily accessible heteroaromatic carboxylic acids and diaryliodonium salts were successfully employed to construct valuable 2-arylindoles and heteroaryl carboxylates in a regioselective fashion. C2-arylated indoles were produced using a Pd-catalyzed decarboxylative strategy in water without any base, oxidant, or ligand. Heteroaryl carboxylates were prepared under metal and base-free conditions. This protocol was successfully utilized to synthesize Paullone, a cyclin-dependent kinase (CDK) inhibitor.
- Arun, Velladurai,Pilania, Meenakshi,Kumar, Dalip
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supporting information
p. 3345 - 3349
(2016/12/14)
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- Deepening the Topology of the Translocator Protein Binding Site by Novel N,N-Dialkyl-2-arylindol-3-ylglyoxylamides
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As a continuation of our studies on 2-phenylindol-3-ylglyoxylamides as potent and selective translocator protein (TSPO) ligands, two subsets of novel derivatives, featuring hydrophilic group (OH, NH2, COOH) at the para-position of the pendent 2
- Barresi, Elisabetta,Bruno, Agostino,Taliani, Sabrina,Cosconati, Sandro,Da Pozzo, Eleonora,Salerno, Silvia,Simorini, Francesca,Daniele, Simona,Giacomelli, Chiara,Marini, Anna Maria,La Motta, Concettina,Marinelli, Luciana,Cosimelli, Barbara,Novellino, Ettore,Greco, Giovanni,Da Settimo, Federico,Martini, Claudia
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p. 6081 - 6092
(2015/08/24)
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- On the mechanism of berberine-INF55 (5-Nitro-2-phenylindole) hybrid antibacterials
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Berberine-INF55 hybrids are a promising class of antibacterials that combine berberine and the NorA multidrug resistance pump inhibitor INF55 (5-nitro-2-phenylindole) together in one molecule via a chemically stable linkage. Previous studies demonstrated the potential of these compounds for countering efflux-mediated antibacterial drug resistance but they didn't establish whether the compounds function as originally intended, i.e. with the berberine moiety providing antibacterial activity and the attached INF55 component independently blocking multidrug resistance pumps, thereby enhancing the activity of berberine by reducing its efflux. We hypothesised that if the proposed mechanism is correct, then hybrids carrying more potent INF55 pump inhibitor structures should show enhanced antibacterial effects relative to those bearing weaker inhibitors. Two INF55 analogues showing graded reductions in NorA inhibitory activity compared with INF55 were identified and their corresponding berberine-INF55 hybrids carrying equivalent INF55 inhibitor structures synthesised. Multiple assays comparing the antibacterial effects of the hybrids and their corresponding berberine-INF55 analogue combinations showed that the three hybrids all show very similar activities, leading us to conclude that the antibacterial mechanism(s) of berberine-INF55 hybrids is different from berberine-INF55 combinations.
- Dolla, Naveen K.,Chen, Chao,Larkins-Ford, Jonah,Rajamuthiah, Rajmohan,Jagadeesan, Sakthimala,Conery, Annie L.,Ausubel, Frederick M.,Mylonakis, Eleftherios,Bremner, John B.,Lewis, Kim,Kelso, Michael J.
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p. 1471 - 1480
(2014/12/11)
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- Cycloisomerization of 2-alkynylanilines to indoles catalyzed by carbon-supported gold nanoparticles and subsequent homocoupling to 3,3′-biindoles
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Elevated by the support: 2-Alkynyl aniline cycloisomerization to indole is catalyzed by cationic Au NPs on a carbon support. Electroneutral and rich 2-aryl indoles are further converted into 3,3′-biindoles by oxidative homocoupling that is readily catalyzed by the Au NPs on carbon, and exclusively but also somewhat sluggishly by the carbon support. Copyright
- Perea-Buceta, Jesus E.,Wirtanen, Tom,Laukkanen, Otto-Ville,Maekelae, Mikko K.,Nieger, Martin,Melchionna, Michele,Huittinen, Nina,Lopez-Sanchez, Jose A.,Helaja, Juho
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supporting information
p. 11835 - 11839
(2013/11/19)
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- Copper catalysed domino decarboxylative cross coupling-cyclisation reactions: Synthesis of 2-arylindoles
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The efficient synthesis of 2-arylindoles and 6H-isoindolo[2,1-a]indol-6-one through copper catalysed domino sp-sp2 decarboxylative cross-coupling and subsequent cyclisation reactions of arylpropiolic acids with 2-iodotrifluoroacetanilide has been described. This methodology also demonstrates that indolo[1,2-c]quinazolin-6(5H)-one can be obtained with the elimination of trifluoromethyl anion.
- Ponpandian, Thanasekaran,Muthusubramanian, Shanmugam
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p. 4248 - 4252
(2012/08/28)
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- Efficient indoles and anilines syntheses employing tert-butyl sulfinamide as ammonia surrogate
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tert-Butyl sulfinamide is an ammonia equivalent for the palladium-catalyzed amination of aryl bromides and aryl chlorides. Using these amine derivatives, it has been observed that indoles and anilines with sensitive functional groups can be readily prepared. This surrogate has also been used for the synthesis of indoles from 2-halophenols using palladium catalyzed cross coupling reaction as the key step.
- Prakash, Anjanappa,Dibakar, Mullick,Selvakumar, Kumaravel,Ruckmani, Kandasamy,Sivakumar, Manickam
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supporting information; experimental part
p. 5625 - 5628
(2011/11/06)
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- Synthesis of berberineefflux pump inhibitor hybrid antibacterials
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This article describes the compact synthesis of two isomeric dual-action hybrid antimicrobials where the 13-position of the antibacterial berberine has been linked via 3′-and 4′-methylene bridges to INF55 (5-nitro-2-phenylindole), an inhibitor of the bacterial NorA multidrug-resistance pump. Copyright Taylor & Francis Group, LLC.
- Bremner, John B.,Kelso, Michael J.
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experimental part
p. 3561 - 3568
(2011/03/17)
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- Radical arylation of phenols, phenyl ethers, and furans
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Radical arylations of parasubstituted phenols and phenyl ethers proceeded with good regioselectivity at the ortho position with respect to the hydroxy or alkoxy group. The reactions were conducted with arenediazonium salts as the aryl radical source, titaniumACHTUNGTRENUNG(III) chloride as the reductant, and diluted hydrochloric acid as the solvent. Substituted biaryls were obtained from hydroxy- and alkoxy-substituted benzylamines, phenethylamines, and aromatic amino acids. The methodology described offers a fast, efficient, and cost-effective new access todiversely functionalized biphenyl alcohols and ethers. Free phenolic hydroxyl groups, aromatic and aliphatic amines, as well as amino acid substructures, are well tolerated. Two examples for the applicability of the methodology are the partial synthesis of a b-secretase inhibitor and the synthesis of a calciumchannel modulator
- Wetzel, Alexander,Pratsch, Gerald,Kolb, Roman,Heinrich, Markus R.
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experimental part
p. 2547 - 2556
(2010/06/17)
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- Copper-catalyzed N-arylation/hydroamin(d)ation domino synthesis of indoles and its application to the preparation of a Chekl/KDR kinase inhibitor pharmacophore
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Inexpensive copper catalysts allow for efficient syntheses of N-aryl-, N-acyl-, or N-H-(aza)in-doles starting from ortho-alkynylbromoarenes. The broad scope of this domino N-arylation/hydro-amin(d)ation process is highlighted by the synthesis of highly fu
- Ackermann, Lutz,Barfuesser, Sebastian,Potukuchi, Harish K.
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supporting information; experimental part
p. 1064 - 1072
(2010/03/03)
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- Palladium-catalyzed cross-couplings of lithium arylzincates with aromatic halides: Synthesis of analogues of isomeridianin G and evaluation as GSK-3β inhibitors
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Several analogues of isomeridianin G have been synthesized using palladium-catalyzed cross-coupling reactions of lithium triorganozincates as a key step. The latter have been prepared by deprotonative lithiation followed by transmetalation using ZnCl
- Seggio, Anne,Priem, Ghislaine,Chevallier, Floris,Mongin, Florence
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experimental part
p. 3617 - 3632
(2010/03/05)
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- Structure-activity relationships of 2-aryl-1H-indole inhibitors of the NorA efflux pump in Staphylococcus aureus
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The synthesis of 22 2-aryl-1H-indoles, including 12 new compounds, has been achieved via Pd- or Rh-mediated methodologies, or selective electrophilic substitution. All three methods were based on elaborations from simple indole precursors. SAR studies on
- Ambrus, Joseph I.,Kelso, Michael J.,Bremner, John B.,Ball, Anthony R.,Casadei, Gabriele,Lewis, Kim
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scheme or table
p. 4294 - 4297
(2009/04/06)
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- Assembly of conjugated enynes and substituted indoles via CuI/amino acid-catalyzed coupling of 1-alkynes with vinyl iodides and 2- bromotrifluoroacetanilides
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(Chemical Equation Presented) Cross-coupling of 1-alkynes with vinyl iodides occurs at 80°C in dioxane catalyzed by CuI/N,N-dimethylglycine to afford conjugated enynes in good to excellent yields. Heating a mixture of 2-bromotrifluoroacetanilide, 1-alkyne, 2 mol % of CuI, 6 mol % of L-proline, and K2CO3 in DMF at 80 °C leads to the formation of the corresponding indole. This conversion involves a CuI/L-proline-catalyzed coupling between aryl bromide and the 1-alkyne followed by a CuI-mediated cyclization process. An ortho-substituent effect directed by NHCOCF3 enables me reaction to proceed under these mild conditions. Both aryl acetylenes and O-protected propargyl alcohol can be applied, leading to 5-, 6-, or 7-substituted 2-aryl and protected 2-hydroxymethyl indoles in good yields. With simple aliphatic alkynes, however, lower yields were observed.
- Liu, Feng,Ma, Dawei
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p. 4844 - 4850
(2008/02/05)
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- 2-Aryl and 2-Heteroaryl Indoles from 1-Alkynes and o- lodotrifluoroacetanilide through a Domino Copper-Catalyzed Coupling-Cyclization Process
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(Matrix presented) A general method for the synthesis of 2-aryl and 2-heteroaryl indoles from aryl iodides and 1-alkynes through a domino copper-catalyzed process is reported. The best results have been obtained with [Cu(phen)(PPh3)2]NO3 in the presence of K 3PO4 in toluene or dioxane at 110°C. 2-Aryl and 2-heteroaryl indoles can also be isolated in good yields by using catalysts derived from Cul and PPh3 in dioxane at 110°C.
- Cacchi, Sandro,Fabrizi, Giancarlo,Parisi, Luca M.
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p. 3843 - 3846
(2007/10/03)
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- Convenient indole synthesis from ethynylanilines with a polymer-supported fluoride
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The cyclization reaction of ethynylanilines having phenyl, alkyl, methoxy, cyano, chloro, and ethoxycarbonyl groups with (polystyrylmethyl)trimethylammonium fluoride in dry MeCN under an argon atmosphere at 100°C proceeded in good yields to give the corresponding indoles without affecting these functional groups. Moreover, the polymer-supported fluoride could be reused for the cyclization reaction when the deprotection reaction of the N-substituted indole with the fluoride ion on resin did not occur under the cyclization conditions.
- Yasuhara, Akito,Suzuki, Naoyuki,Yoshino, Takashi,Takeda, Yousuke,Sakamoto, Takao
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p. 6579 - 6582
(2007/10/03)
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