- Four-Selective Pyridine Alkylation via Wittig Olefination of Dearomatized Pyridylphosphonium Ylides
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Methods to synthesize alkylated pyridines are valuable because these structures are prevalent in pharmaceuticals and agrochemicals. We have developed a distinct approach to construct 4-alkylpyridines using dearomatized pyridylphosphonium ylide intermediates in a Wittig olefination-rearomatization sequence. Pyridine N-activation is key to this strategy, and N-triazinylpyridinium salts enable coupling between a wide variety of substituted pyridines and aldehydes. The alkylation protocol is viable for late-stage functionalization, including methylation of pyridine-containing drugs. This approach represents an alternative to metal-catalyzed sp2-sp3 cross-coupling reactions and Minisci-type processes.
- Dolewski, Ryan D.,Fricke, Patrick J.,McNally, Andrew
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supporting information
p. 21283 - 21288
(2021/08/25)
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- Synthesis of Enaminone-Pd(II) Complexes and Their Application in Catalysing Aqueous Suzuki-Miyaura Cross Coupling Reaction
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A series of Pd(II)-enaminone complexes, termed Pd(eao)2, have been synthesized and characterized. The investigation on the catalytic activities of these new Pd(II)-reagents has proved that the Pd(eao)2-1 possesses excellent catalytic activity for the Suzuki- Miyaura cross coupling reactions of aryl bromides/chlorides with aryl/vinyl boronic acids in the environmentally benign media of aqueous PEG400 at low loading (5 mol‰). The superiority of this Pd(II)-reagent to those commercial Pd(II) and Pd(0) catalysts in catalyzing the reactions has been confirmed by parallel experiments. What's more, Pd(eao)2-2 has been found as a practical catalyst for the homo-coupling reactions of aryl boronic acids.
- Fu, Leiqing,Cao, Xiaoji,Wan, Jie-Ping,Liu, Yunyun
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p. 254 - 258
(2020/01/25)
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- NON-PEPTIDE OPIOID RECEPTOR MODULATORS
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Non-peptide MOR opioid receptor modulators are provided. The compounds exhibit predominantly central activity and are used to treat e.g. opioid addiction. The compounds described herein are generally delivered (administered) in a pharmaceutical compositio
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Page/Page column 16
(2020/03/15)
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- Design, Synthesis, and Biological Evaluation of the Third Generation 17-Cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-[(4′-pyridyl)carboxamido]morphinan (NAP) Derivatives as μ/κ Opioid Receptor Dual Selective Ligands
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μ opioid receptor (MOR) agonists have been widely applied for treating moderate to severe pain. However, numerous adverse effects have been associated with their application, including opioid-induced constipation (OIC), respiratory depression, and addicti
- Zheng, Yi,Obeng, Samuel,Wang, Huiqun,Jali, Abdulmajeed M.,Peddibhotla, Bharath,Williams, Dwight A.,Zou, Chuanchun,Stevens, David L.,Dewey, William L.,Akbarali, Hamid I.,Selley, Dana E.,Zhang, Yan
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supporting information
p. 561 - 574
(2019/01/30)
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- Scope of regioselective Suzuki reactions in the synthesis of arylpyridines and benzylpyridines and subsequent intramolecular cyclizations to azafluorenes and azafluorenones
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The current investigation on regioselective Suzuki reactions of 2,3-dihalopyridines and 2-halo-3-halomethylpyridines yielded the unexplored synthesis of arylpyridines and benzylpyridines bearing synthetic handles for further functionalization. Indeed, the scope of intramolecular cyclizations of arylpyridines and benzylpyridines prepared in this study for the synthesis of azafluorenes and azafluorenones has been investigated.
- Laha, Joydev K.,Patel, Ketul V.,Saima,Pandey, Surabhi,Solanke, Ganesh,Vashisht, Vanya
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supporting information
p. 16069 - 16074
(2018/10/04)
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- Silver-Catalyzed Minisci Reactions Using Selectfluor as a Mild Oxidant
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A new method for silver-catalyzed Minisci reactions using Selectfluor as a mild oxidant is reported. Heteroarenes and quinones both participate in radical C-H alkylation and arylation from a variety of carboxylic and boronic acid radical precursors. Several oxidatively sensitive and highly reactive radical species are successful, providing structures that are challenging to access by other means.
- Galloway, Jordan D.,Mai, Duy N.,Baxter, Ryan D.
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supporting information
p. 5772 - 5775
(2017/11/10)
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- Synthesis of 4-benzylpyridines via Pd-catalyzed CH3-arylation of 4-picoline
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A highly efficient synthesis of 4-benzylpyridines was developed via Pd-catalyzed C(sp3)-H arylation between 4-picoline and aryl halides. It was found that the best yields were achieved with a simple Pd(PPh3)4 catalyst and Cs2CO3 as the base. Compared with the known methods, our reaction does not require the use of a strong organometallic reagent as the base.
- Wu, Jing,Wang, Dadian,Chen, Xiang,Gui, Qingwen,Li, Hua,Tan, Ze,Huang, Genping,Wang, Guangwei
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supporting information
p. 7509 - 7512
(2017/09/27)
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- Newly-generated Al(OH)3-supported Pd nanoparticles-catalyzed Stille and Kumada coupling reactions of diazonium salts, (Het)aryl chlorides
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A ligand-free Pd/Al(OH)3 nano-catalyst which is prepared by one-pot three-component method using Pd(PPh3)4, tetra (ethylene glycol), and aluminum tri-sec-butoxide exhibits excellent catalytic activity in Stille cross-couplings of (Het)aryl chlorides, arenediazonium tetrafluoroborate salts with phenyltributylstannane, respectively, and Kumada couplings of (Het)aryl chlorides with various Grignard reagents. More importantly, these two processes show excellent functional group compatibility with moderate to good yields and they are also versatile with respect to not only (Het)aryl chlorides, but also diazonium salts, and heteroaryl Grignard reagents. The nano-catalyst could also be recycled and reused 5 times without loss of activity and decrease of yield.
- Li, Xing,Zhu, Tingting,Shao, Zhongqi,Li, Yingjun,Chang, Honghong,Gao, Wenchao,Zhang, Yongli,Wei, Wenlong
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supporting information
p. 69 - 75
(2015/12/23)
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- Ether-imidazolium carbenes for Suzuki-Miyaura cross-coupling of heteroaryl chlorides with Aryl/heteroarylboron reagents
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Easily accessible and handled ether-imidazolium chlorides were developed as ligand precursors. The coupling reactions of heteroaryl chlorides with aryl/heteroarylboronic acids and esters were catalyzed by the palladium/ether-imidazolium chloride system with high substrate tolerance to give various heterobiaryls in good to excellent yields.
- Kuriyama, Masami,Matsuo, Seira,Shinozawa, Mina,Onomura, Osamu
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supporting information
p. 2716 - 2719
(2013/07/19)
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- Synthesis of pinacol arylboronates from aromatic amines: A metal-free transformation
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A metal-free borylation process based on Sandmeyer-type transformation using arylamines derivatives as the substrates has been developed. Through optimization of the reaction conditions, this novel conversion can be successfully applied to a wide range of aromatic amines, affording borylation products in moderate to good yields. Various functionalized arylboronates, which are difficult to access by other methods, can be easily obtained with this metal-free transformation. Moreover, this transformation can be followed by Suzuki-Miyaura cross-coupling without purification of the borylation products, which enhances the practical usefulness of this method. A possible reaction mechanism involving radical species has been proposed.
- Qiu, Di,Jin, Liang,Zheng, Zhitong,Meng, He,Mo, Fanyang,Wang, Xi,Zhang, Yan,Wang, Jianbo
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p. 1923 - 1933
(2013/03/29)
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- Intramolecular carbolithiation of N-allyl-ynamides: An efficient entry to 1,4-dihydropyridines and pyridines - Application to a formal synthesis of sarizotan
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We have developed a general synthesis of polysubstituted 1,4-dihydropyridines and pyridines based on a highly regioselective lithiation/6-endo-dig intramolecular carbolithiation from readily available N-allyl-ynamides. This reaction, which has been successfully applied to the formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions.
- Gati, Wafa,Rammah, Mohamed M.,Rammah, Mohamed B.,Evano, Gwilherm
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p. 2214 - 2222
(2013/02/23)
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- De novo synthesis of 1,4-dihydropyridines and pyridines
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An efficient and general method for the synthesis of 1,4-dihydropyridines and pyridines based on a lithiation/isomerization/intramolecular carbolithiation sequence is reported. This procedure provides an efficient, divergent, and straightforward entry to a wide range of polysubstituted dihydropyridines and pyridines starting from readily available N-allyl-ynamides.
- Gati, Wafa,Rammah, Mohamed M.,Rammah, Mohamed B.,Couty, Francois,Evano, Gwilherm
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supporting information; experimental part
p. 9078 - 9081
(2012/07/13)
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- Synthesis of biaryls through a one-pot tandem borylation/Suzuki-Miyaura cross-coupling reaction catalyzed by a palladacycle
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The tricyclohexylphosphane adduct of cyclopalladated ferrocenylimine I exhibited high catalytic activity in the one-pot borylation/Suzuki-Miyaura coupling (BSC) reaction with low catalyst loading (2 mol-%). Various biaryls were obtained in good to excellent yields for 37 examples. This process was applied to aryl and heteroaryl halides (Br and Cl) containing a variety of functional groups and did not require an excess amount of phosphane ligand and the addition of the palladium catalyst in the second step. Cyclopalladated ferrocenylimine I exhibited high catalytic activity in the borylation/Suzuki- Miyaura coupling (BSC) reaction with low catalyst loading. Various unsymmetrical biaryls were obtained ingood to excellent yields in one pot. This protocol was applied to aryl and heteroaryl halides (Br and Cl) containing a variety of functional groups without adding catalyst in the second step. Copyright
- Wang, Lianhui,Cui, Xiuling,Li, Jingya,Wu, Yusheng,Zhu, Zhiwu,Wu, Yangjie
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p. 595 - 603
(2012/03/09)
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- Phosphine-free cross-coupling reaction of halopyridines with arylboronic acids in an ionic liquid: Water mixture
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Palladium acetate-catalysed Suzuki reaction of halopyridines and arylboronic acids has been investigated in roomtemperature ionic liquids in the absence of the phosphine ligand. A significant effect of water on the efficiency of the Suzuki reaction in ionic liquids was observed. The mixture of ionic liquid and water significantly enhanced the rate of the coupling reaction. The separation of the product was easily performed by extraction with diethyl ether and the Pd(OAc)2-[bmim][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate) can be reused six times with only a small loss of reactivity.
- Xin, Bingwei
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experimental part
p. 412 - 415
(2009/06/30)
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- Intermolecular 'oxidative' aromatic substitution reactions of the imidazol-5-yl radical mediated by the 'reductant' Bu3SnH
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The reactivity of the imidazol-5-yl in comparison to the imidazol-2-yl and phenyl radical under the reductive conditions of Bu3SnH, in intermolecular substitution reactions onto various aromatic substrates is reported. The directing effect of the hetero atom or methyl substituent in aromatic substrates was found to be more important than the polarity of the attacking σ-radical in determining the major product isomer. Graphical Abstract
- McLoughlin, Padraig T.F.,Clyne, Mairéad A.,Aldabbagh, Fawaz
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p. 8065 - 8071
(2007/10/03)
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- DECOMPOSITION DU PEROXYDE DE BENZOYLE DANS LES MELANGES BENZENE/X-4 PYRIDINES (X=CH3, H, CN). ETUDE CINETIQUE ET INFLUENCE DES SUBSTITUANTS SUR LA REACTIVITE NUCLEOPHILE ET RADICALAIRE DE L'ATOME D'AZOTE
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Effect of a 4-substituent in the pyridine ring upon the decomposition kinetics of benzoyl peroxide in 4-X pyridine/benzene binary mixtures (X=CH3,H,CN) has been studied.The second-order rate constant for the pyridine-induced decomposition was 2x10-6 lmol-1s-1 and in 4-methylpyridine it was 10-5 lmol-1s-1, a five-fold increase, whereas there was no nucleophilic attack on the peroxide oxygen atoms of benzoyl peroxide by 4-cyanopyridine.The surprisingly high increase of the radical-induced decomposition in 4-cyanopyridine might result from the attack at the nitrogen atom of the pyridine ring by the phenyl radical, the 1-phenylpyridinyl radical being stabilized by the cyano group.
- Vidal, S.,Court, J.,Bonnier, J.M.
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p. 4911 - 4920
(2007/10/02)
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- SYNTHESIS OF 3-AZAFLUORENE AND 2H-2-METHYLINDENOPYRIDINE
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4-Methyl-3-phenylpyridine was isolated from the mixture of four isomeric methylphenylpyridines formed in the condensation of crotonaldehyde with phenylacetaldehyde (β-phenylethanol or phenylacetylene) with ammonia in the presence of a cadmium-calcium phosphate catalyst. 4-Methyl-3-phenylpyridine was converted to 3-azafluorene by catalytic dehydrocyclization.A representative of a new series of pseudoazulenes, viz., 2H-2-methylindeno-pyridine, was obtained by treatment of 3-azafluorene methiodide with sodium hydroxide solution; the product was a crystalline black substance that remained unchanged during storage in air for 1 month.
- Prostakov, N. S.,Radzhan, P. K.,Soldatenkov, A. T.
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p. 1153 - 1156
(2007/10/02)
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