- 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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- Marriage of Peroxides and Nitrogen Heterocycles: Selective Three-Component Assembly, Peroxide-Preserving Rearrangement, and Stereoelectronic Source of Unusual Stability of Bridged Azaozonides
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Stable bridged azaozonides can be selectively assembled via a catalyst-free three-component condensation of 1,5-diketones, hydrogen peroxide, and an NH-group source such as aqueous ammonia or ammonium salts. This procedure is scalable and can produce gram quantities of bicyclic stereochemically rich heterocycles. The new azaozonides are thermally stable and can be stored at room temperature for several months without decomposition and for at least 1 year at-10 °C. The chemical stability of azaozonides was explored for their subsequent selective transformations including the first example of an aminoperoxide rearrangement that preserves the peroxide group. The amino group in aminoperoxides has remarkably low nucleophilicity and does not participate in the usual amine alkylation and acylation reactions. These observations and the 15 pKa units decrease in basicity in comparison with a typical dialkyl amine are attributed to the strong hyperconjugative nN→σ*C-O interaction with the two antiperiplanar C-O bonds. Due to the weakness of the complementary nO→σ*C-N donation from the peroxide oxygens (a consequence of inverse α-effect ), this interaction depletes electron density from the NH moiety, protects it from oxidation, and makes it similar in properties to an amide.
- Alabugin, Igor V.,Belyakova, Yulia Yu.,Korlyukov, Alexander A.,Krivoshchapov, Nikolai V.,Medvedev, Michael G.,Novikov, Roman A.,Radulov, Peter S.,Terentev, Alexander O.,Yaremenko, Ivan A.
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- Synthesis of pyridines and pyrido[2,3-d]pyrimidines by the Lewis acid catalysed Bohlmann-Rahtz heteroannulation reaction
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Lewis acids catalyse the Bohlmann-Rahtz heteroannulation reaction to generate highly functionalised pyridines from enamino esters and alkynones in a single synthetic step. Of the catalysts studied, ytterbium(III) trifluoromethanesulfonate and zinc(II) bromide are the two most efficient for the synthesis of pyridines and pyrido[2,3-d]pyrimidines, from ethyl β-aminocrotonate or 2,6-di-aminopyrimidin-4-one respectively, in up to 94% yield.
- Bagley,Dale,Hughes,Ohnesorge,Phillips,Bower
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- Tailor-made synthesis of fully alkylated/arylated nicotinates by FeCl3-mediated condensation of enamino esters with enones
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A new method for synthesizing polyalkylated/arylated nicotinates is established using a condensation of enamino esters with enones in the presence of FeCl3. This method facilitates the introduction of alkyl or aryl groups at any position on demand, which has not been achieved by other procedures.
- Hirai, Sho,Horikawa, Yurie,Asahara, Haruyasu,Nishiwaki, Nagatoshi
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supporting information
p. 2390 - 2393
(2017/02/23)
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- Bohlmann-Rahtz cyclodehydration of aminodienones to pyridines using N-iodosuccinimide
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Cyclodehydration of Bohlmann-Rahtz aminodienone intermediates using N-iodosuccinimide as a Lewis acid proceeds at low temperature under very mild conditions to give the corresponding 2, 3,6-trisubstituted pyridines in high yield and with total regiocontrol.
- Bagley, Mark C.,Glover, Christian
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experimental part
p. 3211 - 3227
(2010/09/04)
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- Continuous flow processing from microreactors to mesoscale: The Bohlmann-Rahtz cyclodehydration reaction
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The cyclodehydration of a number of Bohlmann-Rahtz aminodienones exemplifies the use of continuous flow processing to transfer operations from commercial microreactors and microwave batch reactors to mesoscale production using different technology platforms, including a microwave flow reactor.
- Bagley, Mark C.,Fusillo, Vincenzo,Jenkins, Robert L.,Lubinu, M. Caterina,Mason, Christopher
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experimental part
p. 2245 - 2251
(2010/07/03)
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- Alpha-substituted arylalkyl phosphonate derivatives
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The present invention relates to novel α-substituted arylalkylphosphonate derivatives and their uses for lowering plasma levels of apo (a), Lp(a), apo B, apo B associated lipoproteins (low density lipoproteins and very low density lipoproteins) and for lo
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(2010/02/11)
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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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- Iodine-catalysed Bohlmann-Rahtz cyclodehydration reactions
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The cyclodehydration of Bohlmann-Rahtz aminodienones is catalysed by iodine in ethanol at room temperature to give 2,3,6-trisubstituted pyridines in excellent yield, with total regiocontrol and without the need for chromatographic purification.
- Bagley, Mark C.,Glover, Christian,Chevis, Duncan
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p. 649 - 651
(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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- One-pot synthesis of pyridines or pyrimidines by tandem oxidation-heteroannulation of propargylic alcohols
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Pyridines and pyrimidines are prepared in a single step from propargylic alcohols by in situ oxidation with o-iodoxybenzoic acid or manganese dioxide and reaction with enamines or amidines, respectively, under either thermal or microwave-assisted conditions in a new one-pot tandem oxidation-heteroannulation procedure. The reaction of a β-ketoester, propargylic alcohol and ammonium acetate, with in situ oxidation, constitutes a highly facile three-component reaction for the synthesis of pyridines that accomplishes four distinct synthetic operations in one-pot, good yield and with total regiocontrol.
- Bagley, Mark C.,Hughes, David D.,Sabo, Halima M.,Taylor, Paul H.,Xiong, Xin
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p. 1443 - 1446
(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 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 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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- Carbon transfer reactions of functionalized oxazolidines and their open chain enamine tautomers to enamine nucleophiles. A facile synthesis of substituted pyridines and ring annulated derivatives
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Oxazolidines substituted at C-2 with -CH2-EW(-CO-, etc.) and capable of existing as ring-chain (enamine) tautomers react with cyclic, acyclic and heterocyclic enamine derivatives in a 1:1 stoi-chiometric manner to provide a versatile synthesis of substituted pyridines and their ring annulated derivatives.
- Singh, Kamaljit,Singh, Jasbir,Singh, Harjit
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p. 935 - 942
(2007/10/03)
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- Synthesis of a new chiral copper(I) complex and its application to stereoselective photoreduction of - (H4edta = ethylenedinitrilotetraacetic acid)
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A chiral bipyridine derivative, 4,4',6,6'-tetramethyl-5,5'-bis-2,2'-bipyridine (L), was newly synthesized.Using its copper(I) complex, +, - (H4edta = ethylenedinitrilotetraacetic
- Sakaki, Shigeyoshi,Ishikura, Hiroyuki,Kuraki, Ko-ichi,Tanaka, Ko-jyoh,Satoh, Takashi,et al.
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p. 1815 - 1820
(2007/10/03)
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- NICOTINIC ACID CROWN ETHERS: SYNTHESIS, COMPLEXATION AND REDUCTION
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2,6-Bis(bromomethyl)nicotinic oxazoline (15), prepared from ethyl 2,6-dimethylnicotinate, was converted into the 1:1-macrocyclic oxazolines 19 and 22 as well as the isomeric macrocyclic dimers 20.Ethyl 2,6-bis(bromomethyl)nicotinate (23), prepared from 6b, was converted to the corresponding 1:1-dibenzo-18-crown-6 macrocyclic analog 24.NMR and mass spectral data were used to ascertain the macrocyclic structures.Reaction of 22 with EtMgBr afforded, after oxidation, the 4-substituted pyridino macrocycle 26 in high yield.However, under identical conditions, the non-oxazoline macrocycle 27 was recovered in toto.
- Newkome, George R.,Marston, Charles R.
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p. 2001 - 2008
(2007/10/02)
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