- C2-Selective silylation of pyridines by a rhodium-aluminum complex
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We have developed a C2-selective mono-silylation of a variety of pyridines using a Rh-Al complex. Both the site- and mono-selectivity are controlledviathe pyridine coordination to the Lewis-acidic Al center prior to the activation of the pyridine C(2)-H bond at the proximal Rh center. A reaction mechanism is proposed based on several mechanistic studies, including the isolation of a (2-pyridyl)silylrhodium intermediate.
- Hara, Naofumi,Uemura, Nao,Nakao, Yoshiaki
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supporting information
p. 5957 - 5960
(2021/06/18)
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- Synthesis of Bis-heteroaryls Using Grignard Reagents and Pyridylsulfonium Salts
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Herein are reported ligand-coupling reactions of Grignard reagents with pyridylsulfonium salts. The method has wide functional group tolerance and enables the formation of bis-heterocycle linkages, including 2,4′-, 2,3′-, and 2,2′-bipyridines, as well as pyridines linked to pyrimidines, pyrazines, isoxazoles, and benzothiophenes. The methodology was successfully applied to the synthesis of the natural products caerulomycin A and E.
- Horan, Alexandra M.,Duong, Vincent K.,McGarrigle, Eoghan M.
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supporting information
p. 9089 - 9093
(2021/11/30)
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- Ligand-to-metal charge transfer of a pyridine surface complex on TiO2for selective dehydrogenative cross-coupling with benzene
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Dehydrogenative cross-coupling (DCC) between pyridine and benzene proceeded selectively using a TiO2 photocatalyst under visible light irradiation at optimized concentrations of the substrates. Visible light induces ligand-to-metal charge transfer (LMCT) between pyridine and a TiO2 surface to give a pyridine radical cation, which produces a pyridyl radical by its deprotonation or oxidation of another pyridine molecule. The pyridyl radical attacks a benzene ring to form an sp2C-sp2C bond and a hydrogen atom is subsequently removed to complete DCC. Selective excitation of the pyridine LMCT complex in the presence of an excess amount of benzene would be the key for higher selectivity. This journal is
- Hishitani, Shinichiro,Naniwa, Shimpei,Yamamoto, Akira,Yoshida, Hisao
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p. 11366 - 11373
(2021/05/31)
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- Visible-light photoexcitation of pyridine surface complex, leading to selective dehydrogenative cross-coupling with cyclohexane
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Upon photoirradiation with visible light, a pyridine molecule adsorbed on a TiO2 surface can be photoexcited to give a pyridine radical cation via ligand-to-metal charge transfer (LMCT) between pyridine and titanium. This leads to dehydrogenative cross-coupling (DCC) between pyridine and cyclohexane with concomitant hydrogen evolution. Since the radical cation can selectively oxidize cyclohexane to a cyclohexyl radical, the cross-coupling between pyridine and cyclohexane proceeds with higher selectivity compared with that in photocatalysis by TiO2 under UV irradiation.
- Naniwa, Shimpei,Tyagi, Akanksha,Yamamoto, Akira,Yoshida, Hisao
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p. 28375 - 28381
(2018/11/30)
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- Copper-catalyzed cross-coupling of aryl-, primary alkyl-, and secondary alkylboranes with heteroaryl bromides
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A method for the Cu-catalyzed cross-coupling of both aryl and alkylboranes with aryl bromides is described. The method employs an inexpensive Cu-catalyst and functions for a variety of heterocyclic as well as electron deficient aryl bromides. In addition, aryl iodides of varying substitution patterns and electronic properties work well.
- Bergmann, Allison M.,Oldham, Adam M.,You, Wei,Brown, M. Kevin
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supporting information
p. 5381 - 5384
(2018/06/01)
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- Chemoselective Synthesis of Polysubstituted Pyridines from Heteroaryl Fluorosulfates
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A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib. A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib.
- Zhang, Enxuan,Tang, Jiaze,Li, Suhua,Wu, Peng,Moses, John E.,Sharpless, K. Barry
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supporting information
p. 5692 - 5697
(2016/04/20)
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- Au-complex containing phosphino and imidazolyl moieties as a bi-functional catalyst for one-pot synthesis of pyridine derivatives
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The complex of Au-L1 containing imidazolyl ring and the phosphine-ligated-Au moiety was synthesized and applied as the efficient bi-functional catalyst for the one-pot sequential condensation/annulation reaction for the synthesis of pyridine derivatives. It was found that, as for Au-L1, the involved imidazolyl group acted as a Lewis base to catalyze the condensation of carbonyl compounds with propargylamine to form the imino intermediate, and the involved Au+-complex species with alkynophilicity corresponded to the subsequent activation of imino-tailed alkynyl to afford dehydropyridine intermediate. The latter proceeded auto-oxidation reaction to afford the pyridine derivatives. The observed sequential catalysis over Au-L1 proved more efficient than that over the mechanical mixtures of the Au-complex (Au-L2) and N-methylimidazole, because the free N-methylimidazole as an N-containing donor competed with the alkyne substrate to coordinate to Au-center. Moreover, Au-L1 exhibited good generality to a wide range of the substrates for the synthesis of 2,3-fused pyridine derivatives and 2-aryl(heteroaryl)-substituted pyridines.
- Yang, Da,Liu, Huan,Wang, Dong-Liang,Lu, Yong,Zhao, Xiao-Li,Liu, Ye
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p. 323 - 330
(2016/09/23)
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- Aerobic C-N bond activation: A simple strategy to construct pyridines and quinolines
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Inspired by the autoxidation processes, a dioxygen induced C-N bond activation of primary alkyl amines was demonstrated toward the synthesis of pyridines and quinolines. The transition-metal free conditions with O2 as the sole oxidant make this transformation very attractive. Notably, the substrate applicability of different kinds of ketones is greatly broadened for this transformation.
- Wu, Kun,Huang, Zhiliang,Liu, Chao,Zhang, Heng,Lei, Aiwen
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supporting information
p. 2286 - 2289
(2015/02/05)
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- Arylation of 2-substituted pyridines via Pd-catalyzed decarboxylative cross-coupling reactions of 2-picolinic acid
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The novel palladium-catalyzed decarboxylative cross-coupling reactions of 2-picolinic acid with aryl and heteroaryl bromides including benzenes, naphthalenes, pyridines and quinolines for C-C bond formation have been successfully achieved. This journal is
- Li, Xinjian,Zou, Dapeng,Leng, Faqiang,Sun, Chunxia,Li, Jingya,Wu, Yangjie,Wu, Yusheng
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supporting information
p. 312 - 314
(2013/02/22)
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- Synthesis, crystal structures, and catalytic activities of palladium imidazole complexes formed by 2-hydroxyethyl group cleavage
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N-4,6-dimethyl-2-pyrimidinylimidazole 1 and its hydroxyethyl derivative 1-(2-hydroxyethyl)-3-(4,6-dimethyl-2-pyrimidinyl)imidazolium chloride 2 have been synthesized and characterized. The attempted synthesis of bis(N-heterocyclic carbene)palladium complexes via the direct reaction of 2 with Pd(OAc)2 results in the unexpected formation of a bis(N-arylimidazole) palladium complex 3. Additionally, the analogous bis(N-methylimidazole) palladium complex 4 has also been synthesized by the above method. Compounds 1-4 were characterized by elemental analysis, IR, and 1H NMR. Additionally, their crystal structures have been determined by X-ray diffraction. Complexes 3 and 4 were found to be efficient catalysts for the Suzuki reaction.
- Xu, Chen,Li, Zhen,Duan, Lu-Meng,Wang, Zhi-Qiang,Fu, Wei-Jun,Hao, Xin-Qi,Song, Mao-Ping
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supporting information; experimental part
p. 373 - 378
(2012/07/31)
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- Metal-free arylation of benzene and pyridine promoted by amino-linked nitrogen heterocyclic carbenes
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An amino-linked nitrogen heterocyclic carbene (amino-NHC), 1-tBu, has been shown to mediate carbon-carbon coupling through the direct C-H functionalization of benzene and pyridine in the absence of a metal catalyst. Using EPR, the first spectroscopic evidence corroborating the single electron transfer mechanism for the metal-free carbon-carbon coupling manifold, as reported by others, is introduced.
- Chen, Wen-Ching,Hsu, Yu-Chen,Shih, Wei-Chun,Lee, Ching-Yu,Chuang, Wen-Han,Tsai, Yi-Fang,Chen, Peter Ping-Yu,Ong, Tiow-Gan
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supporting information; experimental part
p. 6702 - 6704
(2012/07/14)
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- PdCl2(dppf)-catalyzed in situ coupling of 2-hydroxypyridines with aryl boronic acids mediated by PyBroP and the one-pot chemo- and regioselective construction of two distinct aryl-aryl bonds
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We present a PdCl2(dppf)-catalyzed synthesis of 2-arylated pyridine derivatives via the in situ coupling of 2-OH pyridines and boronic acids mediated by PyBroP. In addition, the highly chemo- and regioselective construction of two different aryl-aryl bonds via a one-pot operation has also been demonstrated by the orthogonal use of this method with the Ni-catalyzed Suzuki-Miyaura coupling of phenols.
- Li, Shui-Ming,Huang, Jie,Chen, Guo-Jun,Han, Fu-She
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supporting information; experimental part
p. 12840 - 12842
(2012/01/05)
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- Studies on the amino-heck reactions of unsaturated ketones o-phosphinyloximes for the preparation of substituted pyridines
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The amino-Heck cyclization process has been applied into a range of γ,δ-unsaturated ketone O-diethylphosphinyloximes 1 and δ,ε-unsaturated ketone O-diethylphosphinyloximes 7. Under the specific catalytic conditions developed by us, these substrates were found to preferentially undergo the 6-endo cyclization to give the formation of 2-substituted pyridines 3 and substituted methylpyridines 8, respectively, in moderate to good yields. Besides, several interesting aspects on the effects of phosphinyl groups, solvents, bases and molecular sieves on the regioselectivity of the cyclization of 1 have also been realized.
- Zhu, Jia-Liang,Su, Yi-Lin,Chan, Yu-Hui,Chen, I-Chia,Liao, Chuan-Chen
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experimental part
p. 369 - 387
(2009/06/08)
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- Palladium-catalyzed amino-heck reaction of γ,δ-unsaturated ketone O-diethylphosphinyloximes: A new synthesis of substituted pyrroles and indoles
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γ,δ-Unsaturated ketone O-diethylphosphinyloximes, readily prepared from the corresponding ketones, were used as starting materials for the intramolecular amino-Heck reactions. In the presence of a catalytic amount of Pd(PPh3)4 in DBU, cyclization reactions occurred preferentially via a 5-exo fashion to afford a variety of 2-substituted 5-methyl-1H-pyrroles and several indole derivatives in moderate to high yields. Georg Thieme Verlag Stuttgart.
- Zhu, Jia-Liang,Chan, Yu-Hui
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scheme or table
p. 1250 - 1254
(2009/04/06)
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- Microwave-assisted Suzuki coupling reactions with an encapsulated palladium catalyst for batch and continuous-flow transformations
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This article describes the design, optimisation and development of a Suzuki cross-coupling protocol mediated by an efficient palladium-en-capsulated catalyst (Pd EnCat) under microwave irradiation. The methodology has been used in both batch mode for classical library preparation and in continuous-flow applications furnishing multigram quantities of material. Described is a method that uses direct focused microwave heating whilst applying an external cooling source. This enables a lower than normal bulk temperature to be maintained throughout the reaction period leading to significant improvements in the overall yield and purity of the reaction products. Additional aspects of this novel heating protocol are discussed in relation to the prolonged lifetime and enhanced reactivity of the immobilised catalyst system.
- Baxendale, Ian R.,Griffiths-Jones, Charlotte M.,Ley, Steven V.,Tranmer, Geoffrey K.
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p. 4407 - 4416
(2008/02/07)
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- A versatile method for suzuki cross-coupling reactions of nitrogen heterocycles
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(Chemical Equation Presented) A wide-ranging study of Suzuki reactions which use nitrogen-containing heterocycles is described (see scheme; dba = dibenzylideneacetone, Cy = cyclohexyl). This method is highly versatile (a single procedure was used for all substrates, including boronate esters and trifluoroborates), compatible with a variety of unprotected functionalities (e.g., NH2-and OH-substituted substrates), and efficient even with unactivated aryl chlorides.
- Kudo, Noriaki,Perseghini, Mauro,Fu, Gregory C.
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p. 1282 - 1284
(2007/10/03)
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- Synthesis of 2-pyridylpyridines via aza-Diels-Alder reactions between 3-pyridyl-1,2,4-triazines and some vinyl alkanoates
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New synthetic procedure for 2,ω-bipyridines involving aza-Diels-Alder reaction between 3-(ω-pyridyl)-1,2,4-triazine and vinyl octanoate or decanoate as a dienophile is described. Copyright
- Shintou, Taichi,Ikeuchi, Fumiaki,Kuwabara, Hirokazu,Umihara, Ken,Itoh, Isamu
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p. 836 - 837
(2007/10/03)
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- Efficient preparation of 2-pyridylpyridines using β-N,N-dialkylated aminoacroleins or their equivalent as vinadinium tetrafluoroborate
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Efficient synthetic procedure for 2-pyridylpyridines using β-N,N-dialkylated aminoacroleins or their equivalent as dipiperidyl vinadinium tetrafluoroborate is described. Copyright
- Kuwabara, Hirokazu,Umihara, Ken,Furugori, Yasushi,Itoh, Isamu
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p. 834 - 835
(2007/10/03)
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- PREPARATION OF PYRIDINE DERIVATIVES USING PYRIMIDINIUM DERIVATIVES AS INTERMEDIATES
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A method in which a pyridinium derivative of formula (I) such as 1,3-dimethyl-2,3-dihydro-2-oxopyrimidinium chloride is reacted with an acetyl compound of formula (II) such as 4-acetylpyridine, and then the reaction product is reacted with ammonia or an ammonium salt to form a pyridine derivative of formula (III):Also disclosed is a method for the preparation of the compound of formula (I) from reacting a compound of formula (IV) or (V) with a compound of formula (VI):Also disclosed are two additional alternative methods for the preparation of compounds of formula (I) and related compounds. The substituents are defined in the claims.
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Page/Page column 21-22
(2008/06/13)
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- PROCESS FOR PRODUCING 2-SUBSTITUTED PYRIDINE DERIVATIVE
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The present invention provides a method of producing a pyridine derivative having a substituent at the 2-position of a heterocyclic structure conveniently and with fine selectivity. The present invention relates to a production method of a pyridine derivative having a substituent at the 2-position of a heterocyclic structure, which is represented by the formula (III), which includes reacting a 2-sulfonylpyridine derivative of the formula (I) with an organometallic compound of the formula (II) and the like, and the like: wherein each symbol is as defined in the Description.
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Page/Page column 11
(2008/06/13)
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- Rapid synthesis of CDP840 with 2-pyrimidyl vinyl sulfide as a platform
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A rapid synthesis of CDP840 (a potential therapeutic agent for asthma), using 2-pyrimidyl vinyl sulfide as a platform, has been established. This method includes a stereoselective double Mizoroki-Heck-type arylation, a Liebeskind-Srogltype cross-coupling reaction, and a Pd/C-catalyzed hydrogenation.
- Muraoka, Nobuhiro,Mineno, Masahiro,Itami, Kenichiro,Yoshida, Jun-Ichi
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p. 6933 - 6936
(2007/10/03)
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- Sequential amination/annulation/aromatization reaction of carbonyl compounds and propargylamine: A new one-pot approach to functionalized pyridines
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A general one-pot synthesis of pyridines 4a-t from the reaction of dialkyl acyclic/cyclic ketones 1a-i, methyl, aryl/heteroaryl ketones 1m-r, and aldehydes bearing α-hydrogens 1s,t with propargylamine 2 is described. Gold and copper salts are efficient catalysts for the reaction of ketones with 2. The formation of the pyridines 4 is suggested to proceed through the sequential amination of carbonyl compounds followed by regioselective 6-endo-dig cyclization of the N-propargylenamine (N-propargyldienamine) intermediate 3(5) and aromatization reaction. Whereas the preparation of linear polycyclic pyridine 4i can be carried out by reacting cholestan-3-one 1i with 2, the angular polycyclic pyridine 4j has been obtained starting from cholest-5-en-3-one 1j. Selectivity of the reaction of polycyclic dicarbonyls 1k,1 with 2 has also been investigated.
- Abbiati, Giorgio,Arcadi, Antonio,Bianchi, Gabriele,Di Giuseppe, Sabrina,Marinelli, Fabio,Rossi, Elisabetta
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p. 6959 - 6966
(2007/10/03)
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- Process for the production of 2-pyridylpyridine derivatives
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A process for producing a 2-pyridylpyridine derivative usable as an intermediate for medicines or agricultural chemicals is provided, which does not require expensive metal catalysts, which does not cause environmental problems, and which can be conducted on an industiral scale. The process comprises the step (A) of producing an amidrazone compound from a cyano group-containing heterocyclic compound in water, the step (B) of producing a 1,2,4-triazine compound from the amidrazone compound in water, and the step (C) of producing a 2-pyridylpyridine derivative from the 1,2,4-triazine compound.
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- Stereoselective association of binuclear metallacycles in coordination polymers
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A series of structurally related binuclear metallacycles Cd(NO3)2L]2, where L is an angular exobidentate ligand, have been synthesized. Each metallacycle contains two coordinatively unsaturated, chiral metal centers within a single molecule, and the assembly of these metallacycles into polymeric framework structures has been studied systematically for the first time. Stereoselective homochiral association of [Cd(NO3)2L]2 leads to the formation of helical coordination polymers, whereas meso type association results in nonhelical chain structures. The type of stereoselective aggregation depends on the conditions of self-assembly as well as on ligand functionality. Both helical and nonhelical polymeric complexes have been isolated for the metallacycle [Cd(NO3)2(2,4′-pyacph)]2 (2,4′-pyacph = 2,4′-(4-ethynylphenyl)bipyridyl). Homochiral association results in the formation of helical [Cd(NO3)]∞ chains which link the binuclear [Cd(NO3)2(2,4′-pyacph)]2 metallacycles into racemic two-dimensional sheets which contain both P and M [Cd(NO3)]∞ helices. In contrast, meso-association leads to the formation of nonhelical one-dimensional chains. It is shown that the product of homochiral association is predominately formed at room temperature and that of meso-association is generated at elevated temperatures. Thus, it may be concluded that the homochiral association appears to be energetically less favorable than the meso-association, a conclusion that has been confirmed by theoretical calculations of the crystal lattice energy. Several high-yield syntheses of bipyridyl-type ligands used for metallacyclic assembly are also reported.
- Khlobystov, Andrei N.,Brett, Matthew T.,Blake, Alexander J.,Champness, Neil R.,Gill, Peter M. W.,O'Neill, Darragh P.,Teat, Simon J.,Wilson, Claire,Schroeder, Martin
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p. 6753 - 6761
(2007/10/03)
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- Process for the production of pyridine derivatives
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Provided is a process for producing high-purity pyridine derivatives in a high yield at a low cost without causing pollution problems. Pyridine derivatives are produced by reacting 1,2,4-triazine compound with a vinyl carboxylate having a specific structure.
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- Process for the production of 2-pyridylpyridine derivatives
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A process for producing a 2-pyridylpyridine derivative usable as an intermediate for medicines or agricultural chemicals is provided, which does not require expensive special catalysts and special equipment, which does not cause environmental problems, and which can be conducted on an industiral scale. The process comprises reacting an acetyl-substituted pyridine derivative with a 3-amino acrolein, then reacting the reaction product with ammonia or an ammonium salt.
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-
- PROCESS FOR THE PRODUCTION OF 2-PYRIDYLPYRIDINE DERIVATIVES
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A process for producing a 2-pyridylpyridine derivative usable as an intermediate for medicines or agricultural chemicals is provided, which does not require expensive metal catalysts, which does not cause environmental problems, and which can be conducted on an industiral scale. The process comprises the step (A) of producing an amidrazone compound from a cyano group-containing heterocyclic compound in water, the step (B) of producing a 1,2,4-triazine compound from the amidrazone compound in water, and the step (C) of producing a 2-pyridylpyridine derivative from the 1,2,4-triazine compound.
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- Efficient synthesis of the optically active dihydropyrimidinone of a potent α1A-selective adrenoceptor antagonist
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The convergent synthesis of a potent α1A-selective adrenoceptor antagonist is described. Salient features of the synthesis include the enzymatic resolution of a racemic dihydropyrimidinone and the use of a palladium coupling reaction in the synthesis of 2,4′-dipyridyl.
- Sidler, Daniel R.,Barta, Nancy,Li, Wenjie,Hu, Essa,Matty, Louis,Ikemoto, Nori,Campbell, Jeffrey S.,Chartrain, Michel,Gbewonyo, Kozo,Boyd, Russell,Corley, Edward G.,Ball, Richard G.,Larsen, Robert D.,Reider, Paul J.
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p. 646 - 652
(2007/10/03)
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- Potassium peroxodisulfate: A convenient oxidizing agent for aromatization of 1,4-dihydropyridines
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A series of 13 different 4-substituted 2,6-dimethyl-3,5-diethoxycarbonyl)-1,4-dihydropyridines have been oxidized to pyridine derivatives by potassium peroxodisulfate in dry and wet acetonitrile solution at reflux condition. Formation of two kinds of products has been observed depending on the type of 4-substituent. Addition of water affects only the rate of oxidation.
- Memarian,Mohammadpoor-Baltork,Sadeghi,Samani
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p. 727 - 728
(2007/10/03)
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- Method of production and method of separation of 2,4'-dipyridyl derivatives and methods of production of benzoxazepine derivatives and salts thereof
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PCT No. PCT/JP98/02264 Sec. 371 Date Jan. 21, 1999 Sec. 102(e) Date Jan. 21, 1999 PCT Filed May 22, 1998 PCT Pub. No. WO98/52922 PCT Pub. Date Nov. 26, 1998A method of production of 2,4'-dipyridyl derivatives by a cross coupling reaction of a 2-halopyridine derivative and a 4-halopyridine using a nickel complex catalyst and a method of separation of a 2,4'-dipyridyl derivative from a mixture of dipyridyl isomers containing a 2,2'-dipyridyl derivative, 2,4'-dipyridyl derivative, and 4,4'-dipyridyl by using a dilute aqueous copper sulfate solution to insolubilize and remove the 2,2'-dipyridyl derivative and 4,4'-dipyridyl are disclosed.
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- Pyridine ring formation through the photoreaction of arenecarbothioamides with diene-conjugated carbonyl compounds
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Irradiation of arenecarbothioamides with hexa-2,4-dienal in benzene solution gives 2-arylpyridines in moderate yields.
- Oda, Kazuaki,Nakagami, Rikiji,Nishizono, Naozumi,Machida, Minoru
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p. 2371 - 2372
(2007/10/03)
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- SYNTHESIS OF 4,4'-DIPYRIDYL FROM PYRIDINE, INVOLVING ELECTROLYSIS
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A method has been developed for preparing 4,4'-dipyridyl, which is based on elecrochemical reduction of pyridine to 1,1',4,4'-tetrahydro-4,4'-dipyridyl, followed by its oxidation with sulfur dioxide in organic phase obtained upon electrolysis.The best yield (60-63percent) can be achieved if oxidation if performed at -25 to -30 deg C.The 2,4'- and 2,2'-dipyridyls are formed as by-products.
- Smirnov, Yu. D.,Pavlichenko, V. F.,Tomilov, A. P.
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p. 614 - 616
(2007/10/02)
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- The effect of some additives on the Stille Pd0-catalyzed cross-coupling reaction
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It has been found that the addition of cupric oxide to the cross-coupling reaction (Stille reaction) of 2-tributylstannylpyridine with various halobenzenes and heterocyclic halides leads to a much faster reaction and higher yields. This is also the case for the formation of thieno-1,6-naphthyridine from 2-(2-trimethylstannyl-3-pyridyl)-1,3-dioxolane and t-butyl-N-(2-bromo-3-thienyl)carbamate.
- Gronowitz, Salo,Bjoerk, Patrick,Malm, Johan,Hoernfeldt, Anna-Britta
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p. 127 - 130
(2007/10/02)
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- Palladium-Catalyzed Coupling of Heteroaryl Alkylstannanes with Heteroaryl Halides in the Presence of Silver(I) oxide
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The Pd-catalyzed coupling of heteroaryl trialkylstannanes with a variety of heteroaryl halides has been shown to be greatly promoted by silver(I) oxide.
- Malm, Johan,Bjoerk, Patrick,Gronowitz, Salo,Hoernfeldt, Anna-Britta
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p. 2199 - 2202
(2007/10/02)
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- Theory and Experimental Illustration of Preparative Electrochemistry Using Redox Catalysis of Electron Transfer Initiated Radical Chain Reactions. Application to the Cross-Coupling between Aryl Halides and Phenoxide Ions
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A general equation predicting the yield of electron transfer initiated radical chain reaction (SRN1 and related mechanisms) under preparative electrochemical conditions is given for situations where the electron-transfer activation of the chain is performed by means of a redox mediator.Simple tests, allowing for the choice of proper redox mediator, are given, and their origins established and discussed.The validity and application of this simple model is shown and discussed for the case of the SRN1-like reaction involving di-tert-butylphenoxide as a nucleophile, to afford biaryls of interest for their properties in nonlinear optics.
- Alam, N.,Amatore, C.,Combellas, C.,Thiebault, A.,Verpeaux, J. N.
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p. 6347 - 6356
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF 2,4'-BIPYRIDINE
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2,4'-Bipyridine 6 was synthesized starting from N-ethoxycarbonylpyridinium chloride 1 and 2-benzyloxy-6-bromopyridine 2a or 6-bromo-2-methoxypyridine 2b via 6-benzyloxy-2,4'-bipyridine 3a or 6-methoxy-2,4'-bipyridine 3b and 6-chloro-2,4'-bipyridine 5.
- Shiao, Min-Jen,Tarng, Kai-Yih
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p. 637 - 641
(2007/10/02)
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- ULTRASOUND - PROMOTED COUPLING OF HETEROARYL HALIDES IN THE PRESENCE OF LITHIUM WIRE. NOVEL FORMATION OF ISOMERIC BIPYRIDINES IN A WURTZ - TYPE REACTION
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Ultrasonic irradiation of 2-bromopyridine in THF solution in the presence of lithium wire gives 2,2'-bipyridine, 2,4'-bipyridine and 4,4'-bipyridine, a novel formation of isomers in a Wurtz-type reaction.Similar reaction with 3-bromopyridine mainly results in debromination.
- Osborne, Alan G.,Glass, Kathryn J.,Staley, Miriam L.
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p. 3567 - 3568
(2007/10/02)
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- PREPARATION OF PYRIDYL GRIGNARD REAGENTS AND CROSS COUPLING REACTIONS WITH SULFOXIDES BEARING AZAHETEROCYCLES
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Pyridyl Grignard reagents were prepared from the corresponding iodopyridine and EtMgBr.New cross coupling reactions of the Grignard reagents with azaheterocycles took place on the sulfinyl sulfur atom to afford biazaheteroaryls.
- Furukawa, Naomichi,Shibutani, Tadao,Fujihara, Hisashi
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p. 5845 - 5848
(2007/10/02)
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- General Method for Synthesis of Bipyridines: Palladium Catalyzed Cross-coupling Reaction of Trimethylstannylpyridines with Bromopyridines
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Trimethylstannylpyridines 1 were treated with bromopyridines 2 in the presence of catalytic amount of tetrakis(triphenylphosphine)palladium to give the corresponding bipyridines 3 in moderate to good yields.Nicotelline (6) was similarly synthesized from 2,4-bis(trimethylstannyl)pyridine (5) and 3-bromopyridine (2b).
- Yamamoto, Yutaka,Azuma, Yutaka,Mitoh, Hiroyuki
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p. 564 - 565
(2007/10/02)
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- PHOTOCHEMICAL ARYLATION BY OXIME ESTERS IN BENZENE AND PYRIDINE: SIMPLE SYNTHESIS OF BIARYL COMPOUNDS
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Irradiation of benzophenone O-arenecarbonyloximes in benzene and pyridine affords the corresponding arylbenzenes and arylpyridines, respectively, in high yields.
- Hasebe, Masato,Kogawa, Koichi,Tsuchiya, Takashi
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p. 3887 - 3890
(2007/10/02)
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- The Reactions of Superoxide Ion with Arylhydrazines
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Arylhydrazines react with potassium superoxide to give a variety of products, most of which are derived from interaction of aryl radicals with the solvent.Phenylhydrazine in toluene gives three isomeric metylbiphenyls, diphenylmethane and bibenzyl.In pyridine, the products identified were 2-, 3-, and 4-phenylpyridine.A more complex range of products was obtained from substituted phenylhydrazines.Products are consistent with a process in which superoxide ion abstracts hydrogen atoms from the hydrazines giving radical intermediates, including aryl radicals, which react with the solvents.
- Crank, George,Gately, Garry E.,Makin, Mohammad I. H.
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p. 2499 - 2507
(2007/10/02)
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- On the Reaction of Lithium Diisopropylamide with ?-Deficient Heteroaromatics. A Single Electron Transfer Mechanism
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Evidence is presented in support of one-electron transfer as the key step in the reaction of lithium diisopropylamide (LDA) with ?-deficient heteroaromatics.
- Newkome, George R.,Hager, David C.
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p. 599 - 601
(2007/10/02)
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