18377-65-6Relevant articles and documents
Synthesis of Indoles by Reductive Cyclization of Nitro Compounds Using Formate Esters as CO Surrogates
Ahmed Fouad, Manar,Ferretti, Francesco,Formenti, Dario,Milani, Fabio,Ragaini, Fabio
, p. 4876 - 4894 (2021/09/20)
Alkyl and aryl formate esters were evaluated as CO sources in the Pd- and Pd/Ru-catalyzed reductive cyclization of 2-nitrostyrenes to give indoles. Whereas the use of alkyl formates requires the presence of a ruthenium catalyst such as Ru3(CO)12, the reaction with phenyl formate can be performed by using a Pd/phenanthroline complex alone. Phenyl formate was found to be the most effective CO source and the desired products were obtained in excellent yields, often higher than those previously reported using pressurized CO. The reaction tolerates many functional groups, including sensitive ones like a free aldehydic group or a pendant pyrrole. Detailed experiments and kinetic studies allow to conclude that the activation of phenyl formate is base-catalyzed and that the metal doesn't play a role in the decarbonylation step. The reactions can be performed in a single thick-walled glass tube with as little as 0.2 mol-% palladium catalyst and even on a 2 g scale. The same protocol can be extended to other nitro compounds, affording different heterocycles.
Synthesis of N-Heterocycles by Reductive Cyclization of Nitro Compounds using Formate Esters as Carbon Monoxide Surrogates
Formenti, Dario,Ferretti, Francesco,Ragaini, Fabio
, p. 148 - 152 (2017/12/04)
A series of alkyl and aryl formate esters were evaluated as CO sources in the Pd- and Pd/Ru-catalyzed reductive cyclization of substituted nitro compounds to afford heterocycles, especially indoles. Phenyl formate was found to be the most effective, and it allowed the desired products to be obtained in excellent yields, often higher than those previously reported with pressurized CO. Through detailed experiments and kinetic studies, we were able to discern between metal-catalyzed and base-mediated activation of phenyl formate and confirmed that just the base was effective in catalyzing its decarbonylation.
A porous metal-organic cage constructed from dirhodium paddle-wheels: Synthesis, structure and catalysis
Chen, Lianfen,Yang, Tao,Cui, Hao,Cai, Tao,Zhang, Li,Su, Cheng-Yong
, p. 20201 - 20209 (2015/10/19)
Self-assembly of dirhodium(ii) tetraacetate (Rh2(OAc)4) with a dicarboxylic acid 3,3′-(1,3-phenylenebis(ethyne-2,1-diyl))dibenzoic acid (H2pbeddb) gives rise to a metal-organic cage (MOC) containing Rh-Rh bonds with the formula of [Rh4(pbeddb)4(H2O)2(DMAC)2] (MOC-Rh-1). Single-crystal X-ray diffraction analysis reveals that MOC-Rh-1 shows a lantern-type cage structure, in which a pair of Rh2(CO2)4 paddlewheels is linked by four diacid ligands. The dimensions of the inner cavity of MOC-Rh-1 are 9.5 × 14.8 ?2 (atom-to-atom distances across opposite metal and phenyl groups of pbeddb2-). In the solid phase, the cages are aligned by π-π stacking to form one-dimensional channels (9.5 × 11.1 ?2) through cage windows. Therefore, the crystalline samples of MOC-Rh-1 are porous with the inner and outer cavities of the cages accessible under the heterogeneous condition. MOC-Rh-1 has been fully characterized by EA, TGA, PXRD, IR, UV-vis and XPS measurements. The catalytic tests disclose that activated MOC-Rh-1 is effective in the intramolecular C-H amination of vinyl, dienyl and biaryl azides, leading to the formation of indoles, pyrroles and carbazoles, respectively, and the porous catalyst can be recycled easily and used for at least nine runs without significant loss of activity. In the nine runs, the conversions were in the range of 93-99%, whereas in the tenth run, the conversion was reduced to 78%.
Ligand-free copper-catalyzed one-pot synthesis of indole-2-carboxylic esters
Zhu, Zhiqiang,Yuan, Jiangjun,Zhou, Yirong,Qin, Yang,Xu, Jingshi,Peng, Yiyuan
supporting information, p. 511 - 514 (2014/02/14)
A simple, efficient, and facile synthetic route for the preparation of indole-2-carboxylic esters was described. The cascade reactions of 2-bromobenzaldehyde and glycine ester hydrochloride were promoted by Cu 2O and a base to provide the corresponding products in good yields. Commercially available, inexpensive substrates and reagents were employed under mild reaction conditions in this one-pot operation, which is complementary to existing methods for access to 2-substituted indoles. A simple, efficient, and facile synthetic route to indole-2-carboxylic esters through copper-catalyzed one-pot cascade reactions of commercially available, inexpensive 2-bromobenzaldehyde and glycine ester hydrochloride without the use of any external ligand under mild conditions is reported. Copyright
Ligand-Free Copper-Catalyzed One-Pot Synthesis of Indole-2-carboxylic Esters
Zhu, Zhiqiang,Yuan, Jiangjun,Zhou, Yirong,Qin, Yang,Xu, Jingshi,Peng, Yiyuan
supporting information, p. 511 - 514 (2015/10/05)
A simple, efficient, and facile synthetic route for the preparation of indole-2-carboxylic esters was described. The cascade reactions of 2-bromobenzaldehyde and glycine ester hydrochloride were promoted by Cu2O and a base to provide the corresponding products in good yields. Commercially available, inexpensive substrates and reagents were employed under mild reaction conditions in this one-pot operation, which is complementary to existing methods for access to 2-substituted indoles.
Synthesis of chromeno[3,4-b]indoles as Lamellarin D analogues: A novel DYRK1A inhibitor class
Neagoie, Cleopatra,Vedrenne, Emeline,Buron, Frédéric,Mérour, Jean-Yves,Rosca, Sorin,Bourg, Stéphane,Lozach, Olivier,Meijer, Laurent,Baldeyrou, Brigitte,Lansiaux, Amelie,Routier, Sylvain
, p. 379 - 396 (2012/04/10)
A library of substituted chromeno[3,4-b]indoles was developed as Lamellarin isosters. Synthesis was achieved from indoles after a four-step pathway sequence involving C-3 iodination, a Suzuki cross-coupling reaction, and a one pot deprotection/lactonisation step. Twenty final compounds were tested in order to determine their activity against topoisomerase I and kinases, the two major biological activities of Lamellarins. One newly synthesized derivative exhibited a strong topoisomerase activity comparable to reference compounds such as campthotecin and Lamellarin with only a weak kinase inhibition. Two other lead compounds were identified as new nanomolar DYRK1A inhibitors and several other drugs affected the kinases in the sub-micromolar range. These results will enable us to use the chromeno[3,4-b]indole as a pharmacophore to develop potent treatments for neurological or oncological disorders in which DYRK1A is fully involved.
Iron(II) triflate as a catalyst for the synthesis of indoles by intramolecular C-H amination
Bonnamour, Julien,Bolm, Carsten
, p. 2012 - 2014 (2011/06/28)
A practical iron-catalyzed intramolecular C-H amination reaction and its application in the synthesis of indole derivatives are presented. As a catalyst, commercially available iron(II) triflate is used.
[Fe(F20TPP)Cl] catalyzed intramolecular C-N bond formation for alkaloid synthesis using aryl azides as nitrogen source
Liu, Yungen,Wei, Jinhu,Che, Chi-Ming
supporting information; experimental part, p. 6926 - 6928 (2010/11/16)
The syntheses of alkaloids including indoles, indolines, tetrahydroquinolines, dihydroquinazolinones and quinazolinones have been accomplished in moderate to excellent yields via [Fe(F20TPP)Cl] catalyzed intramolecular C-N bond formation using aryl azides as nitrogen source.
Intramolecular C-H amination reactions: Exploitation of the Rh 2(II)-catalyzed decomposition of azidoacrylates
Stokes, Benjamin J.,Dong, Huijun,Leslie, Brooke E.,Pumphrey, Ashley L.,Driver, Tom G.
, p. 7500 - 7501 (2008/02/09)
Rhodium(II) perfluorobutyrate-mediated decomposition of vinyl azides provides a new, mild entry into Rh2(II) nitrenoid chemistry. This methodology allows rapid access to a variety of complex, functionalized N-heterocycles in two steps from commercially available starting materials. Copyright
Regioselective and versatile synthesis of indoles via intramolecular Friedel-Crafts heteroannulation of enaminones
Cruz, María Del Carmen,Jiménez, Fabiola,Delgado, Francisco,Tamariz, Joaquín
, p. 749 - 755 (2007/10/03)
A new approach is described for the synthesis of substituted indoles 5, through an intramolecular and regioselective Friedel-Crafts cyclization of enaminones 6a-h catalyzed by Lewis acids. Compounds 6 were prepared from the 2-anilinocarbonyl compounds 7, by treatment with DMFDMA under thermal or microwave (MW) irradiation conditions. An alternative and shorter one-pot two-step synthesis of indoles 5 was achieved starting from compounds 7 and promoted by MW radiation, including the elusive 2-acetylindoles 5i-m. Georg Thieme Verlag Stuttgart.
