- Synthesis of NN palladium complexes and six-membered CN palladacycles from 1-N- and 2-N-benzylindazoles
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The reaction of 1-N-benzylindazole (1) and 2-N-benzylindazole (1a) with Na2PdCl4 in MeOH afforded the NN coordinated complexes Pd(1)2Cl2 (2) as the only trans-isomer and Pd(1a)2Cl2 (2a) as the 1:1 mixture of cis and trans isomers. Direct palladation of 1 and 1a using Pd(OAc)2 in AcOH led to the corresponding μ-acetato-dimeric complexes (3 and 3a) with six-membered palladacycles as the mixtures of syn and anti isomers. The reaction of 3 and 3a with LiCl in aqueous acetone gave the μ-Cl-dimeric complexes 5 and 5a where the acetate groups were replaced by Cl. The following addition of PPh3 to the solution of 5 and 5a in CH2Cl2 generated the mononuclear adducts 7 and 7a. NMR spectroscopy data supported the proposed structures of all complexes. The solid-state structure of 7 and 7a was determined by the single-crystal X-ray diffraction methods and indicated a boat conformation of both 6-membered palladacycles.
- Bulygina, Ludmila A.,Khrushcheva, Natalya S.,Klemenkova, Zinaida S.,Lyssenko, Konstantin A.,Peregudov, Aleksander S.,Sokolov, Viacheslav I.
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- Pd-Catalyzed C-H Annulation of Five-Membered Heteroaryl Halides with Norbornene Derivatives
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Complementary to Catellani-type reactions and 1:1 coupling of six-membered halo(hetero)arenes and norbornene (NBE) derivatives, Pd-catalyzed 1:2 coupling of five-membered haloheteroarenes with NBEs was achieved to afford rigid nonplanar heterocycles. Pyra
- Padhi, Birakishore,Kang, Geunhee,Kim, Eunmin,Ha, Jeongmin,Kim, Hyun Tae,Lim, Jeewoo,Joo, Jung Min
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p. 1792 - 1798
(2020/02/04)
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- A VERSATILE LIGAND FOR PALLADIUM-CATALYZED META-C-H FUNCTIONALIZATIONS
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A class of mono-protected 3-amino-2- hydroxypyridine (MPAHP) ligands that enable the meta- C-H arylation of anilines, phenols, phenylacetic acids, and biologically relevant heterocyclic compounds using norbornene as a transient mediator is disclosed. The applicability of this meta-arylation methodology in the pharmaceutical industry is illustrated for heteroaryl substrates and heteroaryl iodide coupling partners, a feat made possible by using the MPAHP ligand. The enabling nature of MPAHP ligands to achieve other meta-C-H functionalization processes is also illustrated by the development of a meta-C-H amination reaction and a meta-C-H alkynylation reaction.
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Page/Page column 96; 97
(2017/11/15)
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- Ligand-Promoted Meta-C-H Arylation of Anilines, Phenols, and Heterocycles
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Here we report the development of a versatile 3-acetylamino-2-hydroxypyridine class of ligands that promote meta-C-H arylation of anilines, heterocyclic aromatic amines, phenols, and 2-benzyl heterocycles using norbornene as a transient mediator. More than 120 examples are presented, demonstrating this ligand scaffold enables a wide substrate and coupling partner scope. Meta-C-H arylation with heterocyclic aryl iodides as coupling partners is also realized for the first time using this ligand. The utility for this transformation for drug discovery is showcased by allowing the meta-C-H arylation of a lenalidomide derivative. The first steps toward a silver-free protocol for this reaction are also demonstrated.
- Wang, Peng,Farmer, Marcus E.,Huo, Xing,Jain, Pankaj,Shen, Peng-Xiang,Ishoey, Mette,Bradner, James E.,Wisniewski, Steven R.,Eastgate, Martin D.,Yu, Jin-Quan
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supporting information
p. 9269 - 9276
(2016/08/05)
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- Indazolium halides as efficient ligands for Pd-catalyzed Suzuki–Miyaura cross-coupling of aryl bromides with arylboronic acids
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The indazolium halides containing various N-substituents have been conveniently prepared and applied in the palladium-catalyzed Suzuki–Miyaura cross-coupling reactions of aryl bromides with arylboronic acids at mild reaction conditions. The cross-coupling reaction provides the desired products in good to high yields. The ease of synthesis and the modularity, and the broad range of aryl bromides and arylboronic acids make this type of ligand attractive and promising for transition metal catalysis.
- Chen, Qian,Mao, Zhuqing,Guo, Fang,Liu, Xiaoshuang
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supporting information
p. 3735 - 3738
(2016/07/26)
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- A general synthesis of diversely substituted indazoles and hetero-aromatic derivatives from o-halo-(het)arylaldehydes or -phenones
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A set of variously substituted indazoles and hetero-aromatic derivatives were synthesized from o-halo-(het)arylaldehydes using a palladium catalyzed amination followed by cyclization. Starting from phenones, this process was extended to give 3-substituted indazoles. Moreover, N-1-substituted-indazoles can be reached by this strategy using an optional selective N-1-alkylation step during the process. This methodology offers a general and easy route for the synthesis of regioselectively substituted indazoles.
- Dubost, Emmanuelle,Stiebing, Silvia,Ferrary, Thibault,Cailly, Thomas,Fabis, Frédéric,Collot, Valérie
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p. 8413 - 8418
(2015/03/04)
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- Pd- and Cu-catalyzed C-H arylation of indazoles
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The palladium- and copper-catalyzed C-H arylation reactions of 1H- and 2H-indazoles with haloarenes are described. A PdCl2/phen/Ag 2CO3/K3PO4 catalytic system is effective for the C-H arylation of 1H- and 2H-indazoles with haloarenes, whereas a less expensive CuI/phen/LiOt-Bu catalytic system is applicable to the C-H coupling of substituted 2H-indazoles and iodoarenes. The utility of newly developed catalyst was demonstrated in the rapid synthesis of YC-1 (an antitumor agent) and YD-3 (platelet anti-aggregating agent). These new reactions represent important direct functionalization tools of indazoles, well-known bioisosteres of pharmaceutically important indole core.
- Hattori, Keika,Yamaguchi, Kazuya,Yamaguchi, Junichiro,Itami, Kenichiro
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experimental part
p. 7605 - 7612
(2012/09/07)
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- N-Alkylation of anilines, carboxamides and several nitrogen heterocycles using CsF-Celite/alkyl halides/CH3CN combination
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It has been found that the N-alkylation of aniline, carboxamides and heterocyclic compounds bearing an acidic hydrogen atom attached to nitrogen can be accomplished with alkyl halides in acetonitrile and cesium fluoride-celite employed as a solid base. In this manner, pyrrole, indole, pyrazole, imidazole, benzimidazole, carbazole, phthalimide, indazole, indoline, 2-pyrrolidinone, piperidine and 1,2,4-triazole can be successfully alkylated. The procedure is convenient, efficient and generally gives rise to the N-alkylated product exclusively.
- Hayat, Safdar,Atta-Ur-Rahman,Iqbal Choudhary,Khan, Khalid Mohammed,Schumann, Wilhelm,Bayer, Ernst
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p. 9951 - 9957
(2007/10/03)
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- SYNTHESIS BY PHASE TRANSFER CATALYSIS OF N-BENZYL, N-DIPHENYLMETHYL AND N-TRIPHENYLMETHYL AZOLES AND BENZAZOLES: PROTON NMR AND CHROMATOGRAPHIC DATA AS A TOOL FOR IDENTIFICATION
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Pyrazole, imidazole, 1,2,4-triazole, indazole and benzotriazole were alkylated under phase transfer catalysis (PTC) with benzyl-, diphenylmethyl- and trityl chloride.Alkylation occured only at the ring nitrogen atoms of the heterocycle, except for indazole in which substitution took also place at position 3.A systematic study of the N- and C-substituted derivatives by proton NMR and chromatographic techniques has been done.
- Claramunt, Rosa M.,Elguero, Jose,Garceran, Rafael
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p. 2895 - 2906
(2007/10/02)
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