- Michael addition of ethyl acetoacetate to α,β-unsaturated oximes in the presence of FeCl3: A novel synthetic route to substituted nicotinic acid derivatives
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The FeCl3-catalyzed reaction of α,β-unsaturated oximes with ethyl acetoacetate resulted in Michael addition followed by ring closure to produce substituted nicotinic acid derivatives in a very efficient way. (C) 2000 Elsevier Science Ltd.
- Chibiryaev,De Kimpe,Tkachev
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- Rhenium-catalyzed regioselective synthesis of multisubstituted pyridines from β-enamino ketones and alkynes via C-C bond cleavage
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A new method is described for the regioselective synthesis of multisubstituted pyridine derivatives. Treatment of N-acetyl β-enamino ketones with alkynes in the presence of the rhenium catalyst, Re 2(CO)10, gives multisubstituted pyridines regioselectively. In this reaction, the N-acetyl moieties are important for the selective formation of the multisubstituted pyridines. This reaction proceeds via insertion of alkynes into a carbon-carbon single bond of β-enamino ketones, intramolecular nucleophilic cyclization, and elimination of acetic acid.
- Yamamoto, Shun-Ichi,Okamoto, Kana,Murakoso, Makiko,Kuninobu, Yoichiro,Takai, Kazuhiko
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supporting information; experimental part
p. 3182 - 3185
(2012/07/28)
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- Non-peptide NK1 receptor ligands based on the 4-phenylpyridine moiety
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The quinoline nucleus of the previously described 4-phenylquinoline-3- carboxamides NK1 receptor ligands 7 has been transformed into either substituted or azole - (i.e., triazole or tetrazole) fused pyridine moieties of compounds 9 and 10, resp
- Giuliani, Germano,Cappelli, Andrea,Matarrese, Mario,Masiello, Valeria,Turolla, Elia Anna,Monterisi, Cristina,Fazio, Ferruccio,Anzini, Maurizio,Pericot Mohr, Gal.La,Riitano, Daniela,Finetti, Federica,Morbidelli, Lucia,Ziche, Marina,Giorgi, Gianluca,Vomero, Salvatore
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experimental part
p. 2242 - 2251
(2011/05/06)
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- Cerium catalysed Michael addition to α,β-unsaturated oximes: A facile and efficient synthesis of substituted pyridines
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CeCl3.7H2O-Nal is found to be an effective catalyst for the synthesis of various tetra-substituted pyridine derivatives via Michael addition of β-dicarbonyl compounds to α,β-unsaturated oximes and subsequent ring closure by cyclo-deh
- Kumar, Sanjay,Saini, Anil,Sandhu, Jagir S.
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p. 429 - 432
(2007/10/03)
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- One-pot multistep Bohlmann-Rahtz heteroannulation reactions: Synthesis of dimethyl sulfomycinamate
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(Chemical Equation Presented) The synthesis of dimethyl sulfomycinamate, the acidic methanolysis product of the sulfomycin family of thiopeptide antibiotics, from methyl 2-oxo-4-(trimethylsilyl)but-3-ynoate is achieved in a 2,3,6-trisubstituted pyridine synthesis that proceeds with total regiocontrol in 13 steps by the Bohlmann-Rahtz heteroannulation of a 1-(oxazol-4-yl)enamine or in 12 steps and 9% yield by three-component cyclocondensation with N-[3-oxo-3-(oxazol-4-yl)propanoyl]serine and ammonia in ethanol.
- Bagley, Mark C.,Chapaneri, Krishna,Dale, James W.,Xiong, Xin,Bower, Justin
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p. 1389 - 1399
(2007/10/03)
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- Ionic liquid promoted simple and efficient synthesis of β-enamino esters and β-enaminones from 1,3-dicarbonyl compounds - One-pot, three-component reaction for the synthesis of substituted pyridines
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A facile enamination of 1,3-dicarbonyl compounds with amines has been developed that affords good to excellent yields of β-enamino esters and β-enaminones using Bronsted acidic ionic liquid 1-methylimidazolium trifluoroacetate ([Hmim]+Tfa-) at room temperature. This methodology has been extended for the synthesis of substituted pyridines in excellent yield by a one-pot, three-component reaction of 1,3-dicarbonyl compounds, ammonium acetate, and alkynone in the presence of [Hmim] +Tfa-.
- Karthikeyan, Ganesan,Perumal, Paramasivan T.
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p. 1746 - 1751
(2007/10/03)
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- A new mild method for the one-pot synthesis of pyridines
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Polysubstituted pyridines are prepared in good yield and with total regiocontrol by the one-pot reaction of an alkynone, 1,3-dicarbonyl compound and ammonium acetate in alcoholic solvents. This new three-component heteroannulation reaction proceeds under mild conditions in the absence of an additional acid catalyst and has been used in the synthesis of dimethyl sulfomycinamate, the acidic methanolysis degradation product of the sulfomycin family of thiopeptide antibiotics.
- Xiong, Xin,Bagley, Mark C.,Chapaneri, Krishna
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p. 6121 - 6124
(2007/10/03)
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- New N-halosuccinimide-mediated reactions for the synthesis of pyridines
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5-Bromo-2,6-dialkylpyridine-4-carboxylates are generated in excellent yield by the Michael addition of enaminoesters and ethynyl ketones followed by bromocyclization using N-bromosuccinimide within 1 hour at 0°C. Treatment of the same aminopentadienone intermediates with N-iodosuccinimide facilitates a low temperature cyclodehydration under very mild conditions to give 2,3,6-trisubstituted pyridines with total regiocontrol.
- Bagley, Mark C.,Glover, Christian,Merritt, Eleanor A.,Xiong, Xin
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p. 811 - 814
(2007/10/03)
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- A novel indium-catalysed synthesis of tetra-substituted pyridine derivatives
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Indium trichloride was found to be an effective catalyst for the synthesis of various tetra-substituted pyridine derivatives via Michael addition of β-dicarbonyl compounds to α,β-unsaturated oximes and subsequent ring closure.
- Saikia, Promod,Prajapati, Dipak,Sandhu, Jagir S.
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p. 8725 - 8727
(2007/10/03)
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- A new one-step synthesis of pyridines under microwave-assisted conditions
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Tri- or tetrasubstituted pyridines are prepared by microwave irradiation of ethyl β-aminocrotonate and various alkynones in a single synthetic step and with total control of regiochemistry. This new one-pot Bohlmann-Rahtz procedure conducted at 170°C in a
- Bagley, Mark C,Lunn, Rebecca,Xiong, Xin
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p. 8331 - 8334
(2007/10/03)
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- A new one-pot three-component condensation reaction for the synthesis of 2,3,4,6-tetrasubstituted pyridines
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The one-pot three-component condensation of a β-ketoester, ammonia and an alkynone in the presence of a Bronsted or Lewis acid or Amberlyst 15 ion exchange resin provided 2,3,6-trisubstituted or 2,3,4,6-tetrasubstituted pyridines directly in good yield and with total regiocontrol.
- Bagley, Mark C.,Dale, James W.,Bower, Justin
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p. 1682 - 1683
(2007/10/03)
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- Synthesis of tetrasubstituted pyridines by the acid-catalysed Bohlmann-Rahtz reaction
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New facile experimental procedures for the preparation of 2,3,4,6-tetrasubstituted pyridines in a single synthetic step have been developed. Thus, an enamino ester and alkynone react by Michael addition-cyclodehydration in a heterocyclisation process that is catalysed by acetic acid, Amberlyst 15 ion exchange resin, zinc(II) bromide or ytterbium(III) triflate. The new one-step Bronsted or Lewis acid-catalysed Bohlmann-Rahtz reaction is a simple, direct and highly expedient method for the synthesis of pyridines that proceeds at a lower reaction temperature and avoids the need to isolate reaction intermediates.
- Bagley, Mark C.,Brace, Christian,Dale, James W.,Ohnesorge, Maren,Phillips, Nathan G.,Xiong, Xin,Bower, Justin
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p. 1663 - 1671
(2007/10/03)
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- A new modification of the Bohlmann-Rahtz pyridine synthesis
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A range of highly functionalised pyridines is prepared from enamino esters and alkynones in a single synthetic step by the use of acetic acid or amberlyst 15 ion exchange resin at 50°C.
- Bagley,Dale,Bower
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p. 1149 - 1151
(2007/10/03)
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- Preparation of ?-Deficient Heteroarylzinc Halides by Oxidative Addition of Active Zinc and Its Palladium-Catalyzed Reaction
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The oxidative addition of active zinc to iodo- and bromo-substituted ?-deficient heteroarenes such as pyridine, pyrimidine, and quinoline gave the corresponding heteroarylzinc halides which were transformed to the arylated and benzoylated derivatives by palladium-catalyzed reaction.
- Sakamoto, Takao,Kondo, Yoshinori,Murata, Naoko,Yamanaka, Hiroshi
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p. 9713 - 9720
(2007/10/02)
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