- Pincerlike manganese complex and preparation method thereof, related ligand and preparation method thereof, catalyst composition and application
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The invention discloses a pincerlike manganese complex, a preparation method thereof, a ligand for preparation, a preparation method of the ligand, a catalyst composition taking the complex as an active component and application of the catalyst composition. According to the pincerlike manganese complex, a cycloalkyl ring is introduced into a ligand framework, and by regulating and controlling the cyclic tension, flexibility and steric hindrance of the cycloalkyl ring, the reactivity and stability of the manganese metal center can be effectively adjusted, and the catalytic activity and substrate applicability of a manganese metal system are remarkably improved. The catalyst composition taking the pincerlike manganese complex as an active component has the advantages of high catalyst activity, wide substrate application range, mild reaction conditions and the like in the process of preparing quinoline or pyridine derivatives by catalyzing dehydrogenation coupling reaction of o-amino aromatic alcohol or gamma-amino alcohol, ketone or secondary alcohol; and the synthesis advantages of low cost and stable performance are embodied, the operation is simple, and the yield is high.
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Paragraph 0159-0165
(2021/07/31)
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- Direct synthesis of ring-fused quinolines and pyridines catalyzed byNNHY-ligated manganese complexes (Y = NR2or SR)
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Four cationic manganese(i) complexes, [(fac-NNHN)Mn(CO)3]Br (Mn-1-Mn-3) and [(fac-NNHS)Mn(CO)3]Br (Mn-4) (whereNNHis a 5,6,7,8-tetrahydro-8-quinolinamine moiety), have been synthesized and evaluated as catalysts for the direct synthesis of quinolines and pyridines by the reaction of a γ-amino alcohol with a ketone or secondary alcohol;NNHS-ligatedMn-4proved the most effective of the four catalysts. The reactions proceeded well in the presence of catalyst loadings in the range 0.5-5.0 mol% and tolerated diverse functional groups such as alkyl, cycloalkyl, alkoxy, chloride and hetero-aryl. A mechanism involving acceptorless dehydrogenation coupling (ADC) has been proposed on the basis of DFT calculations and experimental evidence. Significantly, this manganese-based catalytic protocol provides a promising green and environmentally friendly route to a wide range of synthetically important substituted monocyclic, bicyclic as well as tricyclicN-heterocycles (including 50 quinoline and 26 pyridine examples) with isolated yields of up to 93%.
- Han, Mingyang,Lin, Qing,Liu, Qingbin,Liu, Song,Ma, Ning,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Yan, Xiuli
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p. 8026 - 8036
(2021/12/27)
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- Direct C-H Arylation and Alkylation of Electron-Deficient Heteroaromatic Compounds with Organozinc Reagents
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A direct and convenient method for the C-H arylation and alkylation of electron-deficient N-heteroarenes with readily available organozinc reagents has been developed. This transformation could be readily performed in the absence of a transition-metal catalyst and external oxidants, affording a wide range of substituted heteroarenes with good functional group tolerance in good to excellent yields. The developed simple protocol is scalable to the gram level and suitable for late-stage modification of bioactive molecules and drugs.
- Peng, Zhihua,Yu, Chuanman,Wang, Yilei,Wei, Dongyue,Jiang, Cuiyu
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p. 3678 - 3688
(2021/11/16)
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- Formate-Mediated Cross-Electrophile Reductive Coupling of Aryl Iodides and Bromopyridines
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Two catalytic systems for the formate-mediated cross-electrophile reductive coupling of aryl iodides with 6-bromopyridines are described. Using homogenous rhodium or heterogeneous palladium catalysts, the products of reductive biaryl cross-coupling could
- Schwartz, Leyah A.,Spielmann, Kim,Swyka, Robert A.,Xiang, Ming,Krische, Michael J.
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p. 298 - 301
(2020/10/19)
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- Palladium-Catalyzed Cascade Reactions of I-Ketonitriles with Arylboronic Acids: Synthesis of Pyridines
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This study presents the first example of the Pd-catalyzed cascade reactions of 5-oxohexanenitrile with arylboronic acids, affording important synthon 2-methylpyridines that can be further translated through C(sp3)-H functionalization to construct pyridine derivatives. Furthermore, this chemistry allows 5-oxo-5-Arylpentanenitrile to react with arylboronic acids to provide unsymmetrical 2,6-diarylpyridines. This protocol paves the way for the practical and atom economical syntheses of valuable pyridines with broad functional groups in moderate to excellent yields under mild conditions.
- Chen, Jiuxi,Hu, Maolin,Li, Renhao,Liu, Jichao,Qi, Linjun,Shao, Yinlin,Yao, Xinrong,Zhao, Zhiwei,Zhen, Qianqian
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p. 114 - 119
(2020/03/25)
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- Synthesis of Asymmetrical 2,6-Diarylpyridines from Linear α,β,γ,δ-Unsaturated Ketones by Addition of Ammonium Formate Followed by Annulation
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A simple and efficient method has been established for the synthesis of asymmetrical 2,6-diarylpyridines by cyclization of α,β,γ,δ-unsaturated ketones with ammonium formate under air atmosphere. The reaction is metal-free and operationally convenient from readily available starting materials. Thirty-three examples have been presented, most of which show good yields.
- Chen, Rener,Gao, Yejun,Ma, Yongmin
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p. 3875 - 3882
(2019/10/11)
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- 4-HO-TEMPO-Catalyzed Redox Annulation of Cyclopropanols with Oxime Acetates toward Pyridine Derivatives
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A 4-HO-TEMPO-catalyzed redox strategy for the synthesis of pyridines through the annulation of cyclopropanols and oxime acetates has been developed. This protocol features good functional group tolerance and high chemoselectivity and also promises to be efficient for the late-stage functionalization of skeletons of drugs and natural products. Mechanism studies indicate that the reaction involves the in situ generated α,β-unsaturated ketones and imines as the key intermediates, which are derived from cyclopropanols and oxime acetates via a TEMPO/TEMPOH redox cycle, respectively. The pyridine products are formed as a result of annulation of enones with imines followed by TEMPO-catalyzed oxidative aromatization by excess oxime acetates. This method not only realizes the TEMPO-catalyzed redox reaction but also broadens the frontiers for TEMPO in catalysis.
- Zhan, Jun-Long,Wu, Meng-Wei,Wei, Dian,Wei, Bang-Yi,Jiang, Yu,Yu, Wei,Han, Bing
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p. 4179 - 4188
(2019/05/01)
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- Phosphine Ligand-Free Ruthenium Complexes as Efficient Catalysts for the Synthesis of Quinolines and Pyridines by Acceptorless Dehydrogenative Coupling Reactions
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A series of phosphine-free Ru(III)/Ru(II) complexes of NH functionalized N?N?N pincer ligands exhibit excellent activity for acceptorless dehydrogenative coupling (ADC) of secondary alcohols with 2-aminobenzyl or γ-amino alcohols to quinolines and pyridines. Ru(III) complexes [LRuCl3] (L=6-(3-R1,5-R2-1H-pyrazol-1-yl)-N-(pyridin-2-yl)pyridin-2-amine; 1 a: R1=R2=H (L1); 1 b: R1=R2=Me (L2); 1 c: R1=H, R2=CF3 (L3); 1 d: R1=H, R2=Ph (L4); 1bMe: L=6-(3,5-dimethyl-1H-pyrazol-1-yl)-N-methyl-N-(pyridin-2-yl)pyridin-2-amine (L2Me)) were obtained by refluxing RuCl3 ? xH2O with the corresponding ligand in EtOH. Five Ru(II) complexes [LRu(DMSO-κS)Cl2] (2 a: L=L1; 2 b: L=L2; 2 c: L=L3; 2 d: L=L4; 2bMe: L=L2Me) were formed by reducing the corresponding Ru(III) complex in refluxing EtOH. The latter complexes could also be prepared directly by refluxing Ru(DMSO)4Cl2 with the corresponding ligand in EtOH. These Ru(III) and Ru(II) complexes, especially 1 b/2 b, exhibited high catalytic efficiency and broad functional group tolerance in ADC reactions of secondary alcohols with 2-aminobenzyl or γ-amino alcohols to quinolines and pyridines. A detail mechanistic study indicated the Ru(III) complex was reduced into the Ru(II) species, which is the active catalytic center for ADC via a Ru?H/N?H bifunctional outer-sphere mechanism. This protocol provides a reliable, atom-economical and environmentally benign procedure for C?N and C?C bond formation.
- Guo, Bin,Yu, Tian-Qi,Li, Hong-Xi,Zhang, Shi-Qi,Braunstein, Pierre,Young, David J.,Li, Hai-Yan,Lang, Jian-Ping
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p. 2500 - 2510
(2019/05/10)
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- Intermolecular Oxidative Radical Addition to Aromatic Aldehydes: Direct Access to 1,4- and 1,5-Diketones via Silver-Catalyzed Ring-Opening Acylation of Cyclopropanols and Cyclobutanols
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A novel silver-catalyzed ring-opening acylation of cyclopropanols and cyclobutanols is described. The reaction proceeds under mild and neutral conditions and provides a facile access to nonsymmetric 1,4- and 1,5-diketones in promising yields with broad substrate scope. Mechanistic studies including DFT calculations suggest the involvement of an uncommon water-assisted 1,2-HAT process, which is strongly exothermic and thus promotes addition of carbon radicals to aldehydes. In contrast to traditional reductive radical addition protocols, this work represents the first example of the intermolecular oxidative radical addition to aldehydes, thus offering a novel strategy for the direct synthesis of acyclic ketones from readily accessible aldehydes.
- Che, Chao,Qian, Zhaosheng,Wu, Mingchang,Zhao, Ying,Zhu, Gangguo
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p. 5665 - 5673
(2018/05/14)
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- Preparation method for 1,5-dikenotic compound
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The invention discloses a preparation method for a 1,5-dikenotic compound. The method comprises the steps that naphthenic alcohol in II structure, aromatic aldehyde in III structure, catalyzer, oxidizer, and solvent are added and mixed to from a reaction
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Paragraph 0099-0102
(2018/07/30)
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- Preparation method of 1,4-diketone compound
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The invention discloses a preparation method of a 1,4-diketone compound. The preparation method comprises the following steps: adding and mixing naphthenic alcohol of a structure shown in a formula II, aromatic aldehyde of a structure shown in a formula I
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Paragraph 0099-0102
(2020/04/29)
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- C6-Selective Direct Arylation of 2-Phenylpyridine via an Activated N-methylpyridinium Salt: A Combined Experimental and Theoretical Study
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An elegant pre-activation strategy, based on the formation of N-methylpyridinium iodide salts for C6-selective direct arylation of 2-phenylpyridines using Pd/Cu cooperative catalysis, has been developed. By this methodology, a wide range of unsymmetrical 2, 6-diarylpyridines were synthesized with high reactivity and regioselectivity as well as good functional group tolerance. In particular, challenging substrates bearing electron donating groups (EDGs), such as OMe, NMe2, were also successfully employed in this reaction. Deuterium incorporation studies revealed that the C?H bond acidity is improved significantly in N-methylpyridinium salts compared with their N-Oxide and N-iminopyridinium ylide counterparts, thus solving the long-standing problem associated with previous strategies for the synthesis of diaryl pyridines. Finally, the control experiments and DFT calculations supported a Pd-catalyzed and Cu-mediated mechanism in which a carbenoid copper species that is formed in-situ from N-methylpyridinium salts, participates in a Pd-catalyzed arylation followed by an iodide-promoted N-demethylation process. (Figure presented.).
- Yin, Changzhen,Zhong, Kangbao,Li, Wenjing,Yang, Xiao,Sun, Rui,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Lan, Yu,Fu, Haiyan,Chen, Hua
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p. 3990 - 3998
(2018/09/12)
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- NNN-Ruthenium Catalysts for the Synthesis of Pyridines, Quinolines, and Pyrroles by Acceptorless Dehydrogenative Condensation
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The bidentate ruthenium complex (HO-C5H3N-CO-C5H3N-C5H4N)Ru(CO)2Cl2 (2) could transform to a tridentate product (HO-C5H3N-CO-C5H3N-C5H4N)Ru(CO)Cl2 (3), which further reacted with CH3ONa in the presence of PPh3 to convert to two complexes [(OC5H3N-CO-C5H3N-C5H4N)Ru(PPh3)2(CO)]Cl- (4) and [(OC5H3N-CO-C5H3N-C5H4N)Ru(PPh3)(CO)Cl] (5), via -OH deprotonation. The catalytic coupling cyclizations of secondary alcohols with amino alcohols were investigated, and complex 3 exhibited the highest activity. The coupling reactions proceeded in air with only 0.2 mol % catalyst loading and had a broad scope for the synthesis of pyridines, quinolones, and pyrroles.
- Deng, Danfeng,Hu, Bowen,Yang, Min,Chen, Dafa
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p. 2386 - 2394
(2018/07/31)
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- Copper-catalyzed direct C-H arylation of pyridine N-oxides with arylboronic esters: One-pot synthesis of 2-arylpyridines
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The first example of the copper-catalyzed direct C-H arylation of pyridine N-oxides with arylboronic esters has been developed, leading to a wide range of 2-arylpyridines in a one-pot synthesis with moderate to good yields without an additional reductant. This transformation allows for rapid access to a variety of 2-arylpyridines using an inexpensive catalytic system that would be more difficult to access with traditional methods. Thus, this method represents a simple and practical procedure to access 2-arylpyridines.
- Shen, Yan,Chen, Jiuxi,Liu, Miaochang,Ding, Jinchang,Gao, Wenxia,Huang, Xiaobo,Wu, Huayue
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supporting information
p. 4292 - 4295
(2014/04/17)
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- Highly regioselective assembly of Di- or trisubstituted pyridines from arynes, isocyanides, and 3-bromo- or 3-acetoxypropynes
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A facile synthetic method for the preparation of di- and trisubstituted pyridines with high regioselectivity through an intramolecular pericyclization strategy is disclosed. The multicomponent reaction of isocyanides, arynes, and 3-bromopropyne affords disubstituted pyridines in good yields. In contrast, the use of 3-acetoxypropyne results in the formation of trisubstituted pyridines through intramolecular pericyclization of an in situ formed azatriene. In this way, desirable pyridines can be constructed in a one-pot manner. The preparation of di- or trisubstituted pyridines with high regioselectivity through the multicomponent reaction of isocyanides, arynes, and 3-bromo or 3-acetoxypropyne is described. The pyridine ring is constructed through intramolecular pericyclization of an in situ generated azatriene intermediate. The pyridine products are assembled effectively in a one-pot manner under mild conditions. Copyright
- Sha, Feng,Shen, Hui,Wu, Xin-Yan
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supporting information
p. 2537 - 2540
(2013/06/05)
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- Mn(III)-mediated formal [3+3]-annulation of vinyl azides and cyclopropanols: A divergent synthesis of azaheterocycles
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Mn(III)-mediated formal [3+3]-annulation has been developed using readily available vinyl azides and cyclopropanols with a wide range of substituents. Vinyl azides were successfully applied as a three-atom unit including one nitrogen to prepare pyridines and σ-lactams by the reactions with monocyclic cyclopropanols as well as to construct 2-azabicyclo[3.3.1] and 2-azabicyclo[4.3.1] frameworks with bicyclic cyclopropanols, bicyclo[3.1.0]hexan-1-ols, and bicyclo[4.1.0]heptan-1-ols. These reactions were initiated by a radical addition of β-carbonyl radicals, generated by the one-electron oxidation of cyclopropanols with Mn(III), to vinyl azides to give iminyl radicals, which cyclized with the intramolecular carbonyl groups. In addition, application of the present methodology to a synthesis of the quaternary indole alkaloid, melinonine-E, was accomplished.
- Wang, Yi-Feng,Toh, Kah Kah,Ng, Eileen Pei Jian,Chiba, Shunsuke
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supporting information; experimental part
p. 6411 - 6421
(2011/06/19)
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- Efficient, mild and completely regioselective synthesis of substituted pyridines
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Addition of Grignard reagents to pyridine N-oxides in THF at low temperature (-78 to -20 °C) and treatment with TFAA provides an efficient general procedure for synthesis of substituted pyridines. The method is compatible with a range of functional groups such as esters, halogens and nitriles.
- Andersson, Hans,Sainte-Luce Banchelin, Thomas,Das, Sajal,Olsson, Roger,Almqvist, Fredrik
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supporting information; experimental part
p. 3384 - 3386
(2010/07/06)
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- Mn(III)-mediated reactions of cyclopropanols with vinyl azides: Synthesis of pyridine and 2-azabicyclo[3.3.1]non-2-en-1-ol derivatives
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(Chemical Equation Presented) A Mn(III)-mediated divergent synthesis of substituted pyridines and 2-azabicyclo[3.3.1]non-2-en-1-ol derivatives was exploited using readily available vinyl azides and cyclopropanols with a wide range of substituents. In short, the reactions of vinyl azides with monocyclic cyclopropanol provided pyridines in the presence of Mn(acac)3 (1.7 equiv), whereas those with bicyclic cyclopropanols led to the formation of 2-azabicyclo[3.3.1]non-2-en-1-ol derivatives using a catalytic amount of Mn(acac)3. These reactions may be initiated by a radical addition of β-keto radicals, generated by the one-electron oxidation of cyclopropanols, to vinyl azides to give iminyl radicals, which would cyclize with the intramolecular carbonyl groups. In addition, versatile transformations of 2-azabicyclo[3.3.1] non-2-en-1-ol to 2-azabicyclo[3.3.1]nonane or -non-2-nen frameworks were developed.
- Wang, Yi-Feng,Chiba, Shunsuke
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supporting information; experimental part
p. 12570 - 12572
(2010/01/30)
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- One-pot double suzuki- miyaura couplings: Rapid access to nonsymmetrical tri(hetero)aryl derivatives
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We describe a one-pot, simultaneous Suzuki- Miyaura cross-coupling of two different aryl boronic acids with symmetrical dibromo aryl and heterocyclic substrates to give as major products the unsymmetrical disubstituted tri(hetero)aryl derivatives. Yields
- Beaumard, Floriane,Dauban, Philippe,Dodd, Robert H.
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supporting information; experimental part
p. 1801 - 1804
(2009/08/15)
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- An expedient, flexible and convergent access to selectively protected 1,5-dicarbonyl compounds. Applications to the synthesis of 2,6-disubstituted pyridines and thiopyridines
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Intermolecular addition of 2-oxoalkyl radicals generated from the corresponding S-alkyl-O-ethyl dithiocarbonates on vinyl ketals afforded selectively protected 1,5-dicarbonyl compounds in good yields. These key-intermediates can be converted into a plethora of useful substances. Transformations to pyridines and thiopyridines were given as examples. Georg Thieme Verlag Stuttgart.
- Boivin, Jean,Carpentier, Floriane,Jrad, Rafik
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p. 1664 - 1672
(2007/10/03)
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- Selectivities in the formation of pyridines and pyrimidines by ammonia-induced cyclocondensations of vinamidiniums
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Arylvinamidines (2-, 3- or 4-aryl-4-(N,N-dimethyl)amino-1-azabuta-1,3-dienes), generated from 1,1,5,5-tetramethyl-2- or 3-phenyl-1,5-diazapentadienium salts, cyclocondense orientation-specifically under two regioselections forming 1-4'+4-3' and 1-2'+4-1' bonds on exposure to ammonia. The initial cyclates aromatise eliminatively to give mixtures of diarylpyridines and arylpyrimidines. The 2-arylvinamidines do not participate as 2-centre reactants and their 4-aryl isomers not as 4-centre reactants in the cyclocondensations which appear to be stepwise and not concerned. Reasons for the selective participation appear to be that the required eliminations from the initial cyclates are disfavoured in the first case and that a geometric factor prevents cyclate-formation in the second.
- Natarajan Balasubrahmanyam,Jeyashri, Bommuswamy,Narayanan Namboothiri, Irishi N.
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p. 8127 - 8142
(2007/10/02)
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