- Direct Synthesis of Benzoylpyridines from Chloropyridines via a Palladium-Carbene Catalyzed Carbonylative Suzuki Cross-Coupling Reaction
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The use of N-heterocyclic carbene-type ligands with palladium catalysts allows the activation of chloropyridines and chloroquinoline towards carbonylative cross-coupling with phenylboronic acid for the synthesis of unsymmetrical biaryl ketones.
- Maerten, Eddy,Hassouna, Fatima,Couve-Bonnaire, Samuel,Mortreux, André,Carpentier, Jean-Fran?ois,Castanet, Yves
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- Selective ortho C-H Activation of Pyridines Directed by Lewis Acidic Boron of PBP Pincer Iridium Complexes
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Transition-metal mediated C-H functionalization has emerged as a powerful method in the chemistry relevant to the synthesis of pharmaceuticals, agrochemicals, and advanced materials. Because organic molecules typically contain multiple types of C-H bonds, selective C-H functionalization is a major ongoing challenge. C-H activation of heteroatom-containing organics has often been approached via the use of the directing effect, whereby the coordination to the basic heteroatom directs the reactive metal center to a specific C-H bond. We now report a different approach where the nitrogen donor in pyridine derivatives coordinates to an ancillary Lewis acidic boryl ligand directly attached to the metal (iridium) center, as opposed to the metal itself. This topology directs the iridium center to activate a different C-H bond than in the cases of directing donor coordination to the metal. Using this strategy, we demonstrate ortho-regiospecific C-H activation of pyridines and an example of the subsequent functionalization via C-C bond formation.
- Shih, Wei-Chun,Ozerov, Oleg V.
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Read Online
- Micelle-Enabled Suzuki-Miyaura Cross-Coupling of Heteroaryl Boronate Esters
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We report a micellar protocol for Suzuki-Miyaura cross-coupling of heteroaryl boronic esters with aryl or heteroaryl halides. The micellar catalysis enables this coupling reaction to run under mild conditions, which avoids the decomposition of heteroaryl boronate esters and allows for high chemoselectivity for cross-coupling reaction with 6-chloropridine-2-boronic ester. The micellar protocol expands the scope of the cross-coupling reaction with challenging heteroaryl boronic esters and complements the existing cross-coupling methods for construction of heterobiaryl building blocks.
- Guo, Pengfei,Zhang, Hao,Zhou, Jianguang,Gallou, Fabrice,Parmentier, Michael,Wang, Hui
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p. 7523 - 7527
(2018/06/04)
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- A new aromatic amine compound and its preparation and use (by machine translation)
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The invention discloses a novel aromatic amine compound, and the compound molecule of the general formula: Wherein R1 , R2 , R3 Are hydrogen atom or the carbon atom number 1 - 30 alkyl or the carbon atom number 6 - 50 car
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Paragraph 0083-0085
(2017/08/14)
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- Cross-coupling study of iodo/chloropyridines and 2-chloroquinoline with atom-economic triarylbismuth reagents under Pd-catalysis
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This study describes the palladium-catalyzed couplings of iodopyridines, chloropyridines, and chloroquinoline with atom-economic BiAr3 reagents in sub-stoichiometric loadings. Mono-arylations of iodo and chloropyridines produced arylpyridines i
- Rao, Maddali L.N.,Dhanorkar, Ritesh J.
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p. 338 - 349
(2015/03/04)
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- Synthesis and characterization of hydrophilic theophylline base compounds and their use as ligands in the microwave assisted Suzuki-Miyaura couplings of halopyridines in water Dedicated to the memory of Prof. Dr. Armando Cabrera Ortiz pioneer of Catalysis in Mexico. Great Researcher but above all a Great Human Being
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Xanthine derivatives, caffeine (L1), theobromine (L2), theophylline (L3), 7-(β-hydroxyethyltheophylline) (L4), (7-(2,3-dihydroxypropyl)theophylline) (L5), and theophylline 7-acetic acid (L6) and the acetylated derivatives of the later three (L7-L9) were employed as ligands for the in situ palladium catalyzed Suzuki-Miyaura cross couplings of a series of halogenated pyridines. Optimized conditions were found where the diacetylated ligand (L8) was determined to be the best for this process, producing good to excellent yields in the couplings of halogenated anilines with phenylboronic acid under mild reaction conditions in water using microwave irradiation.
- Conelly-Espinosa, Patricia,Toscano, Ruben A.,Morales-Morales, David
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p. 5841 - 5845
(2015/01/09)
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- Discovery of amide replacements that improve activity and metabolic stability of a bis-amide smoothened antagonist hit
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A bis-amide antagonist of Smoothened, a seven-transmembrane receptor in the Hedgehog signaling pathway, was discovered via high throughput screening. In vitro and in vivo experiments demonstrated that the bis-amide was susceptible to N-acyl transferase mediated amide scission. Several bioisosteric replacements of the labile amide that maintained in vitro potency were identified and shown to be metabolically stable in vitro and in vivo.
- Brown, Matthew L.,Aaron, Wade,Austin, Richard J.,Chong, Angela,Huang, Tom,Jiang, Ben,Kaizerman, Jacob A.,Lee, Gary,Lucas, Brian S.,McMinn, Dustin L.,Orf, Jessica,Rong, Minqing,Toteva, Maria M.,Xu, Guifen,Ye, Qiuping,Zhong, Wendy,Degraffenreid, Michael R.,Wickramasinghe, Dineli,Powers, Jay P.,Hungate, Randall,Johnson, Michael G.
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scheme or table
p. 5206 - 5209
(2011/10/09)
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- The AZARYPHOS family of ligands for ambifunctional catalysis: Syntheses and use in ruthenium-catalyzed anti-markovnikov hydration of terminal alkynes
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The family of AZARYPHOS (aza-aryl-phosphane) phosphane ligands, containing a phosphine unit and sterically shielded nitrogen lone pairs in the ligand periphery, is introduced as a tool for developing ambifunctional catalysis by the metal center and nitrogen lone pairs in the ligand sphere. General synthetic strategies have been developed to synthesize over 25 examples of structurally diverse (6-aryl-2pyridyl)phosphanes (ARPYPHOS), (6alkyl-2-pyridyl)phosphanes (ALPY-PHOS), 4,6-disubsituted l,3-diazin-2ylphosphanes or l,3,5-triazin-2- ylphosphanes, quinazolinylphosphanes, quinolinylphosphanes, and others. The scalable syntheses proceed in a few steps. The incorporation of AZARYPHOS ligands (L) into complexes [RuCp(L)2(MeCN)][PF6] (Cp = cyclopentadieny1)gives catalysts for the anti-Markovnikov hydration of terminal alkynes of the highest known activities. Electronic and steric ligand effects modulate the reaction kinetics over a range of two orders of magnitude. These results highlight the importance of using structurally diverse ligand families in the process of developing cooperative ambifunctional catalysis by a metal and its ligand.
- Hintermann, Lukas,Dang, Tuan Thanh,Labonne, Aurelie.,Kribber, Thomas,Xiao, Li,Naumov, Pance
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supporting information; experimental part
p. 7167 - 7179
(2010/02/28)
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- Practical routes to 2,6-disubstituted pyridine derivatives
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We report the synthesis of a series of 2,6-disubstituted pyridines in a straightforward manner starting from readily available 2-substituted pyridines. The main sequence involves a selective ?-lithiation reaction with halogen functionalization followed by
- Vandromme, Lucie,Reissig, Hans-Ulrich,Groeper, Susie,Rabe, Juergen P.
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experimental part
p. 2049 - 2055
(2009/04/04)
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- Palladium-N-heterocyclic carbene an efficient catalytic system for the carbonylative cross-coupling of pyridine halides with boronic acids
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Carbonylative cross-coupling of different pyridyl halides with various boronic acids was studied using catalytic systems constituted of N-heterocyclic carbene type ligands and palladium. These systems easily obtained in situ from the corresponding imidazolium salt and palladium acetate appear more efficient toward bromopyridines than catalysts based on hindered and basic alkylphosphines such as tricyclohexylphosphine. Their higher efficiency was also evidenced by coupling using chloro- or dichloropyridines and chloroquinolines, which practically do not react with catalytic systems based on phosphines.
- Maerten, Eddy,Sauthier, Mathieu,Mortreux, André,Castanet, Yves
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p. 682 - 689
(2007/10/03)
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- Reaction of N-fluoropyridinium fluoride with isonitriles: A convenient route to picolinamides
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Reaction of N-fluoropyridinium fluoride generated in situ with a series of isonitriles led to the formation of the corresponding picolinamides in good yields. A similar reaction sequence for quinoline yielded the respective derivatives of 2-quinoline carboxylic acid. The proposed reaction mechanism involves the intermediate formation of a highly reactive carbene species.
- Kiselyov, Alexander S.
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p. 2279 - 2282
(2007/10/03)
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- Aminoalkoxide-mediated formation and stabilization of phenylpyridyllithium: Straightforward access to phenylpyridine derivatives
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It is shown that lithium aggregates promoted the efficient metalation of phenylpyridines and stabilization of phenylpyridyllithium. The BuLi-LiDMAE superbase prevented dimerization or nucleophilic addition encountered with t-BuLi or n-BuLi. The reported s
- Gros, Philippe,Fort, Yves
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p. 2028 - 2029
(2007/10/03)
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- HEPATITIS C VIRUS INHIBITORS
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Hepatitis C virus inhibitors are disclosed having the general formula:(I) wherein R1, R2, R3, R', B, Y and X are described in the description. Compositions comprising the compounds and methods for using the compounds toinhibit HCV are also disclosed.
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Page 547-548
(2008/06/13)
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- Palladium-catalyzed carbonylative coupling of pyridine halides with aryl boronic acids
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The carbonylative Suzuki cross-coupling of a variety of mono-iodopyridines and bromopyridines (1a,b, 3a-c, 5) catalyzed by palladium-phosphane systems has been studied to prepare benzoylpyridine derivatives (2, 4, 6). The selectivity and the rate of the reaction are highly dependent on the reaction conditions, i.e. nature of the palladium catalyst precursor, solvent, temperature and CO pressure. The main side-products arise from direct, non-carbonylative cross-coupling. Under optimized conditions, benzoylpyridines are recovered in high yields (80-95%). The order of reactivity decreases from iodo- to bromopyridines and from 2-, 4- to 3-substituted halopyridines. The reactivity of dihalopyridines has been investigated; 2,6-dibromopyridine (7) and 3,5-dibromopyridine (11) are selectively transformed into either the corresponding benzoyl-phenylpyridine (8, 12) or the corresponding dibenzoylpyridine (9, 13). Dissymmetric 2,5-dihalopyridines (15a,b) are transformed into 2-benzoyl-5-bromopyridine (16) or 2,5-dibenzoylpyridine (17) in high yields.
- Couve-Bonnaire, Samuel,Carpentier, Jean-Fran?ois,Mortreux, André,Castanet, Yves
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p. 2793 - 2799
(2007/10/03)
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- Unusual C-6 lithiation of 2-chloropyridine-mediated by BuLi-Me2N(CH2)2OLi. New access to 6-functional-2-chloropyridines and chloro-bis-heterocycles
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Formula Presented The reaction of 2-chloropyridine with alkylithium generally results in nucleophilic addition leading to the loss of chlorine atom while exclusive directed ortho metalation is obtained using LDA. Herein it is shown that the BuLi-Me2
- Choppin, Sabine,Gros, Philippe,Fort, Yves
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p. 803 - 805
(2007/10/03)
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- New synthetic routes to 3-, 5-, and 6-aryl-2-chloropyridines
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The efficient synthesis of 3-, 5-, and 6-aryl-2-chloropyridines via the facile preparation of 5-(dimethylamino)aryl-substituted pentadienyl nitriles and cyclization with hydrochloric acid is described. This approach allows for the introduction of other electron-withdrawing substituents on the pyridine ring as well as the preparation of the desired unsubstituted arylpyridines. Some differences in the rates of cyclization of the pentadienyl nitriles as well as the yields of chloropyridines were observed that depended on the position and degree of substitution in the aryl substituent. The arylpentadienyl nitriles 5 and 6 could also be converted directly into the corresponding 2-aminopyridines.
- Church,Trust,Albright,Powell
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p. 3750 - 3758
(2007/10/02)
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- SELECTIVE REDUCTION OF THE N-O BOND IN HETEROAROMATIC N-OXIDES BY TiCl4/SnCl2.
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Heteroaromatic N-oxides bearing various functionalities are readily and selectively converted under mild conditions into the corresponding bases using TiCl4/SnCl2.
- Balicki, Roman,Kaczmarek, Lukasz,Malinowski, Marek
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p. 897 - 900
(2007/10/02)
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- Titanium(0) Reagents; 2. A Selective and Efficient Deoxygenation of Halogen Containing Heteroaromatic N-Oxides
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Following successful reductions of unfunctionalized heteroaromatic N-oxides by titanium(0), we applied this method to halogenated aromatic N-oxides to give the deoxygenated halogeno derivatives in 90-95percent yield.
- Malinowski, Marek,Kaczmarek, Lukasz
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p. 1013 - 1015
(2007/10/02)
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- IPSO-SUBSTITUTION REACTIONS OF 2- AND 4-SULFONYLPYRIDINES WITH GRIGNARD REAGENTS
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The reactions of 2-sulfonylpyridines with Grignard reagents proceeded via an ionic path to give only the corresponding ipso-substitution products, while 4-sulfonylpyridines afforded mainly a mixture of both the substitution and coupling products on treatment with Grignard reagents.
- Furukawa, Naomichi,Tsuruoka, Masayuki,Fujihara, Hisashi
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p. 3337 - 3340
(2007/10/02)
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