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Masaru Kimura - One of the best experts on this subject based on the ideXlab platform.
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Formation of 4H‐Azepine by the Electrophilic Reaction of a 2‐Methoxyazepinium Ion and Analysis of the Sigmatropic Isomerization
European Journal of Organic Chemistry, 2006Co-Authors: Christopher E. J. Cordonier, Kyosuke Satake, Hideki Okamoto, Masaru KimuraAbstract:2-Aryl-2H-, 3-aryl-3H-, and 4-aryl-4H-Azepine were formed by the novel, electrophilic, πLUMO-controlled reaction of the 2-methoxyazepinium ion, generated in situ by the reaction of TiCl4 with 2,7-dialkoxy-2H-Azepine and an aryl compound, for which the kinetic parameters of the sigmatropic hydrogen rearrangement of the 4H-Azepine was measured. The substitution and hydrogen shift of the azepinium ion were analyzed with DFT studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
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Reaction of 2-methoxy-3H-Azepine with NBS: efficient synthesis of 2-substituted 2H-Azepines.
The Journal of organic chemistry, 2005Co-Authors: Christopher E. J. Cordonier, Kyosuke Satake, Mikihiko Atarashi, Yousuke Kawamoto, Hideki Okamoto, Masaru KimuraAbstract:[reaction: see text] The reaction of 2-methoxy-3H-Azepines, in the presence or absence of a nucleophile, with N-bromosuccinimide (NBS) gave a regioselective 1,4-adduct from which the corresponding 2H-Azepine derivatives were formed via base-promoted hydrogen bromide elimination, generally in moderate to quantitative yield. Competitive formation of 4-bromo-2-methoxy-3H-Azepine by electrophilic substitutuion or 3H-azepin-2-yl 2H-azepin-2-yl ether by transetherification was minimized at lower reaction temperatures. Quantitative substitution of 2-(2',4',6'-trichlorophenoxy)-2H-Azepine derivatives, formed in moderate yield from the respective 3H-Azepine and NBS in the presence of 2,4,6-trichlorophenol (TCP), by various nucleophiles gave the corresponding 2-substituted 2H-Azepine. Among these nucleophiles were alkanethiol and alkylamine that are not tolerated in the reaction of 3H-Azepine and NBS.
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Nucleophilic reactions of 5-tert-butyl-2-methoxy-3H-Azepine with alkoxides and alkyllithium reagents
Bulletin of the Chemical Society of Japan, 2003Co-Authors: Yasuhiro Kubota, Kyosuke Satake, Hideki Okamoto, Ryusuke Ikui, Masaru KimuraAbstract:The reaction of 5-tert-butyl-2-methoxy-3H-Azepine (2a) with sodium alkoxides gave 2-alkoxy-3H-Azepine derivatives 3–6 by nucleophilic transetherification. The treatment of 2a with tert-butyllithium also yielded 2,5-di-tert-butyl-3H-Azepine (7); however, the reaction of 2a and methyllithium gave the expected 5-tert-butyl-2-methyl-3H-Azepine (8) along with unexpected 5-tert-butyl-2,2-dimethyl-2,3-dihydro-1H-Azepine (9), but also 5,5′-di(tert-butyl)-2,2′-methylenedi(3H-Azepine) (11), the structure of which was found to be tautomerized 5-tert-butyl-2-(5-tert-butyl-2,3-dihydro-1H-azepin-2-ylidenemethyl)-3H-Azepine (12). The energy profile for the observed tautomerization is discussed based on ab initio DFT calculations and kinetic measurements.
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Plausible mechanism for the formation of 2-methoxy-2h-Azepine derivatives from 3H-Azepines using bromine and NBS
HETEROCYCLES, 2003Co-Authors: Kyosuke Satake, Christopher E. J. Cordonier, Yasuhiro Kubota, Yuexian Jin, Masaru KimuraAbstract:Formation of 2-bromo-4-t-butyl-7-methoxy-2H-Azepine and 4-t-butyl-7-methoxy-2-succinimidyl-2H-Azepine by the respective reactions of 5-t-butyl-2-methoxy-3H-Azepine with bromine and NBS suggests a plausible mechanism for the conversion of 3H-Azepine to 2H-Azepine as 1,4-addition of an electrophile and a consequent 1,2-dehydrobromination. Different from the case of cycloheptatriene, reaction of 3H-Azepine with bromine did not give any delocalized ionic species.
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selenium dioxide oxidations of dialkyl 3h Azepines the first synthesis of 2 azatropone from oxidation of 2 5 di tert butyl 3h Azepine
Journal of Organic Chemistry, 2000Co-Authors: Shizuka Takami, Kyosuke Satake, Yuko Tawada, Akihide Oshida, Setsuo Kashino, Masaru KimuraAbstract:Oxidation reactions of 2,5- and 3,6-di-tert-butyl-3H-Azepines (1 and 2) with selenium dioxide (SeO2) were performed. The oxidation of 1 with SeO2 gave 3-tert-butyl-7,7-dimethyl-4-oxo-octa-2,5-dienal 3 in 36% yield, 4-tert-butyl-5-(3,3-dimethyl-2-oxo-butylidene)-1,5-dihydro-pyrrol-2-one 4 in 13% yield, 2,6-di-tert-butyl-2-pyridinecarbaldehyde 5 in 12% yield, and 4,7-di-tert-butyl-2H-azepin-2-one (2-azatropone) 6 in 6% yield, respectively. Oxidation of 2 with SeO2 gave 2,2-dimethyl-1-[2-(5-tert-butyl)-pyridyl]propanol 7 in 55% yield, and 3,6-di-tert-butyl-2H-Azepine 8 in 5% yield, respectively. We found that selenium dioxide oxidation of 1 affords 4-oxo-octa-2,5-dienal 3 by a new ring cleavage reaction of 1, and we described the first synthesis of 2-azatropone 6 from this oxidation of 1. In the case of 2, pyridylpropanol 7 was obtained as the major product. We now report in detail result of these oxidation reactions, which have led to the synthesis of a novel azatropone derivative.
Young Kee Kang - One of the best experts on this subject based on the ideXlab platform.
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Altering the Cyclization Modes: Temperature-Dependent Intramolecular 7-Endo-Dig vs 6-Endo-Dig Electrophilic Ring Closures
Organic Letters, 2017Co-Authors: Maloy Nayak, Young Kee KangAbstract:In an attempt to construct 10-acyl-5H-benzo[e]pyrrolo[1,2-a]Azepines via acid-catalyzed intramolecular alkyne carbonyl metathesis, two distinctive modes of cyclization were revealed to depend on the reaction temperatures. 5H-Benzo[e]pyrrolo[1,2-a]Azepine-1-carbaldehydes with a substituent at the C11 position were obtained as major products at 90 °C as a result of intramolecular 7-endo-dig cyclization, while 6-endo-dig ring closure by electrophilic addition of nitrogen of the pyrrole to a vinyl cation generated under acidic medium followed by an unprecedented domino rearrangement process was observed at 40 °C in some cases, resulting in 5-aryl-11H-benzo[d]pyrrolo[1,2-a]Azepine-1-carbaldehydes along with the former products.
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Altering the Cyclization Modes: Temperature-Dependent Intramolecular 7-Endo-Dig vs 6-Endo-Dig Electrophilic Ring Closures
2017Co-Authors: Maloy Nayak, Young Kee Kang, Ikyon KimAbstract:In an attempt to construct 10-acyl-5H-benzo[e]pyrrolo[1,2-a]Azepines via acid-catalyzed intramolecular alkyne carbonyl metathesis, two distinctive modes of cyclization were revealed to depend on the reaction temperatures. 5H-Benzo[e]pyrrolo[1,2-a]Azepine-1-carbaldehydes with a substituent at the C11 position were obtained as major products at 90 °C as a result of intramolecular 7-endo-dig cyclization, while 6-endo-dig ring closure by electrophilic addition of nitrogen of the pyrrole to a vinyl cation generated under acidic medium followed by an unprecedented domino rearrangement process was observed at 40 °C in some cases, resulting in 5-aryl-11H-benzo[d]pyrrolo[1,2-a]Azepine-1-carbaldehydes along with the former products
Maloy Nayak - One of the best experts on this subject based on the ideXlab platform.
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Altering the Cyclization Modes: Temperature-Dependent Intramolecular 7-Endo-Dig vs 6-Endo-Dig Electrophilic Ring Closures
Organic Letters, 2017Co-Authors: Maloy Nayak, Young Kee KangAbstract:In an attempt to construct 10-acyl-5H-benzo[e]pyrrolo[1,2-a]Azepines via acid-catalyzed intramolecular alkyne carbonyl metathesis, two distinctive modes of cyclization were revealed to depend on the reaction temperatures. 5H-Benzo[e]pyrrolo[1,2-a]Azepine-1-carbaldehydes with a substituent at the C11 position were obtained as major products at 90 °C as a result of intramolecular 7-endo-dig cyclization, while 6-endo-dig ring closure by electrophilic addition of nitrogen of the pyrrole to a vinyl cation generated under acidic medium followed by an unprecedented domino rearrangement process was observed at 40 °C in some cases, resulting in 5-aryl-11H-benzo[d]pyrrolo[1,2-a]Azepine-1-carbaldehydes along with the former products.
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Altering the Cyclization Modes: Temperature-Dependent Intramolecular 7-Endo-Dig vs 6-Endo-Dig Electrophilic Ring Closures
2017Co-Authors: Maloy Nayak, Young Kee Kang, Ikyon KimAbstract:In an attempt to construct 10-acyl-5H-benzo[e]pyrrolo[1,2-a]Azepines via acid-catalyzed intramolecular alkyne carbonyl metathesis, two distinctive modes of cyclization were revealed to depend on the reaction temperatures. 5H-Benzo[e]pyrrolo[1,2-a]Azepine-1-carbaldehydes with a substituent at the C11 position were obtained as major products at 90 °C as a result of intramolecular 7-endo-dig cyclization, while 6-endo-dig ring closure by electrophilic addition of nitrogen of the pyrrole to a vinyl cation generated under acidic medium followed by an unprecedented domino rearrangement process was observed at 40 °C in some cases, resulting in 5-aryl-11H-benzo[d]pyrrolo[1,2-a]Azepine-1-carbaldehydes along with the former products
Kyosuke Satake - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of 2-Methoxy-3H-Azepine Derived Compounds Through the Thermal Reaction between Alkylnitrobenzene and Tributylphosphine
2015Co-Authors: Siti Mariyah Ulfa, Hideki Okamoto, Kyosuke SatakeAbstract:Although photolysis of phenyazide has been widely reported to give 3 H -Azepine, the thermal deoxygenation reaction of alkylnitrobenzene derived similar products hitherto unexplored. Novel synthesis of 2-methoxy-3 H -Azepine derivatives was carried out using alkylnitrobenzene with tributylphosphine (Bu 3 P) reacted at 150°C for 24 hours in the presence of methanol. Reaction of m -nitrobenzene with the above methods gave two isomers of 3 H -Azepine, namely, 2-methoxy-6-methyl-3 H -Azepine and 2-methoxy-4-methyl-3 H -Azepine in 61%. Reaction of 2,3-dimethylnitrobenzene with Bu 3 P afforded the three isomers, that is, 2-methoxy-6,7-dimethyl-3 H -Azepine; 2-methoxy-3,4-dimethyl-3 H -Azepine and 7-methoxy-5,6-dimethyl-4 H -Azepine. Reaction of 3,5-dimethylnitrobenzene gave the sole product of 2-methoxy-4,6-dimethyl-3 H -Azepine in 42%. In contrast, reaction of 2,6-dimethylnitrobenzene didn’t give any product because the steric effect of methyl groups attached on C2 and C6. Structure elucidation of all novel products have confirmed by HETCOR.
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Formation of 4H‐Azepine by the Electrophilic Reaction of a 2‐Methoxyazepinium Ion and Analysis of the Sigmatropic Isomerization
European Journal of Organic Chemistry, 2006Co-Authors: Christopher E. J. Cordonier, Kyosuke Satake, Hideki Okamoto, Masaru KimuraAbstract:2-Aryl-2H-, 3-aryl-3H-, and 4-aryl-4H-Azepine were formed by the novel, electrophilic, πLUMO-controlled reaction of the 2-methoxyazepinium ion, generated in situ by the reaction of TiCl4 with 2,7-dialkoxy-2H-Azepine and an aryl compound, for which the kinetic parameters of the sigmatropic hydrogen rearrangement of the 4H-Azepine was measured. The substitution and hydrogen shift of the azepinium ion were analyzed with DFT studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
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Reaction of 2-methoxy-3H-Azepine with NBS: efficient synthesis of 2-substituted 2H-Azepines.
The Journal of organic chemistry, 2005Co-Authors: Christopher E. J. Cordonier, Kyosuke Satake, Mikihiko Atarashi, Yousuke Kawamoto, Hideki Okamoto, Masaru KimuraAbstract:[reaction: see text] The reaction of 2-methoxy-3H-Azepines, in the presence or absence of a nucleophile, with N-bromosuccinimide (NBS) gave a regioselective 1,4-adduct from which the corresponding 2H-Azepine derivatives were formed via base-promoted hydrogen bromide elimination, generally in moderate to quantitative yield. Competitive formation of 4-bromo-2-methoxy-3H-Azepine by electrophilic substitutuion or 3H-azepin-2-yl 2H-azepin-2-yl ether by transetherification was minimized at lower reaction temperatures. Quantitative substitution of 2-(2',4',6'-trichlorophenoxy)-2H-Azepine derivatives, formed in moderate yield from the respective 3H-Azepine and NBS in the presence of 2,4,6-trichlorophenol (TCP), by various nucleophiles gave the corresponding 2-substituted 2H-Azepine. Among these nucleophiles were alkanethiol and alkylamine that are not tolerated in the reaction of 3H-Azepine and NBS.
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Nucleophilic reactions of 5-tert-butyl-2-methoxy-3H-Azepine with alkoxides and alkyllithium reagents
Bulletin of the Chemical Society of Japan, 2003Co-Authors: Yasuhiro Kubota, Kyosuke Satake, Hideki Okamoto, Ryusuke Ikui, Masaru KimuraAbstract:The reaction of 5-tert-butyl-2-methoxy-3H-Azepine (2a) with sodium alkoxides gave 2-alkoxy-3H-Azepine derivatives 3–6 by nucleophilic transetherification. The treatment of 2a with tert-butyllithium also yielded 2,5-di-tert-butyl-3H-Azepine (7); however, the reaction of 2a and methyllithium gave the expected 5-tert-butyl-2-methyl-3H-Azepine (8) along with unexpected 5-tert-butyl-2,2-dimethyl-2,3-dihydro-1H-Azepine (9), but also 5,5′-di(tert-butyl)-2,2′-methylenedi(3H-Azepine) (11), the structure of which was found to be tautomerized 5-tert-butyl-2-(5-tert-butyl-2,3-dihydro-1H-azepin-2-ylidenemethyl)-3H-Azepine (12). The energy profile for the observed tautomerization is discussed based on ab initio DFT calculations and kinetic measurements.
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Plausible mechanism for the formation of 2-methoxy-2h-Azepine derivatives from 3H-Azepines using bromine and NBS
HETEROCYCLES, 2003Co-Authors: Kyosuke Satake, Christopher E. J. Cordonier, Yasuhiro Kubota, Yuexian Jin, Masaru KimuraAbstract:Formation of 2-bromo-4-t-butyl-7-methoxy-2H-Azepine and 4-t-butyl-7-methoxy-2-succinimidyl-2H-Azepine by the respective reactions of 5-t-butyl-2-methoxy-3H-Azepine with bromine and NBS suggests a plausible mechanism for the conversion of 3H-Azepine to 2H-Azepine as 1,4-addition of an electrophile and a consequent 1,2-dehydrobromination. Different from the case of cycloheptatriene, reaction of 3H-Azepine with bromine did not give any delocalized ionic species.
Varlamov A.v. - One of the best experts on this subject based on the ideXlab platform.
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Conversion of 2-ethyl- 3, 3, 5, 5-tetramethyl- and 2-ethyl- 1, 3, 3, 5, 5-pentamethyl-1, 2, 4, 5-tetra- hydro-3H-benz-2-Azepines by the action of ethyl propiolate
'Springer Science and Business Media LLC', 2020Co-Authors: Voskressensky L.g., Borisova T.n., Kulikova L.n., Sorokina E.a., Kleimenov A.v., Tolkunov S.v., Varlamov A.v.Abstract:It has been shown that, on interacting 2-ethyl-3, 3, 5, 5-tetramethyl- and 2-ethyl-1, 3, 3, 5, 5-pentamethyl-1, 2, 4, 5-tetrahydro-3H-benz-2-Azepines with ethyl propiolate in methanol, fission of the Azepine ring occurs at the C(1)-N(2) bond involving a molecule of solvent. The indicated Azepines do not react with acetylenedicarboxylic acid ester under these conditions. © 2009 Springer Science+Business Media, Inc
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Synthesis and conversions of substituted 4,5-dihydro-3H-spiro[benz-2-Azepine-3,1′-cyclohexanes]
'Springer Science and Business Media LLC', 2020Co-Authors: Varlamov A.v., Zubkov F.i., Lazareva E.v., Chernyshev A.i., Grudinin D.g.Abstract:On oxidizing substituted 1,2,4,5-tetrahydro-3H-spiro[benz-2-Azepine-3,1′-cyclohexanes]with potassium permanganate under phase-transfer catalysis conditions the corresponding 4,5-dihydro derivatives are formed in quantitative yield. By the action of allyl- and benzylmagnesium halides 5-methyl-4,5-dihydro-3H-spiro[benz-2-Azepine-3,1′-cyclohexane] is converted into 5-methyl-1,2,4,5- tetrahydro-1-allyl(benzyl)-3H-spiro[benz-2-Azepine-3,1′-cyclohexane], and by reaction with phenoxyketene and dichlorocarbene into the corresponding 2-oxoazetidino[4,1-a]- and 1,1-dichloroaziridino[3,1-a]benz-2-Azepines
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Reactions of 4,5-dihydro-5-methyl-3H-spiro[benz-2-Azepine-3-cyclohexane] N-oxide with some nucleophilic reagents
Латвийский институт органического синтеза Латвийской академии наук Springer New York Consultants Bureau, 2020Co-Authors: Varlamov A.v., Chernyshev A.i., Grudinin D.g., Levov A.n., Golovtsov N.i., Borisov R.s.Abstract:4,5-Dihydro-5-methyl-3H-spiro[benz-2-Azepine-3-cyclohexane] N-oxide reacted with cyanide ion and isopropyl magnesium bromide to give the corresponding 1-cyano- and 1-isopropyl-4,5-dihydro-5-methyl- 3H-spiro[benz-2-Azepine-3-cyclohexane], but reaction with phenyl magnesium bromide, benzyl magnesium chloride, and nitromethane gave cyclic hydroxylamines: 1-substituted N-hydroxy-1,2,4,5-tetrahydro-5- methyl-3H-spiro[benz-2-Azepine-3-cyclohexanes] which were oxidized to the corresponding nitrones
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[3+2] Cycloaddition of dimethyl acetylenedicarboxylate, methyl acrylate, and ethyl acrylate to 4,5-dihydro-5-methyl-3h-spiro[benz-2-Azepine-3,1′- cyclohexane] N-oxide
Латвийский институт органического синтеза Латвийской академии наук Springer New York Consultants Bureau, 2020Co-Authors: Varlamov A.v., Zubkov F.i., Chernyshev A.i., Turchin K.f., Levov A.n.Abstract:The cycloaddition of methyl acrylate and ethyl acrylate to 4,5-dihydro-5-methyl-3H-spiro[benz-2-Azepine-3,1′-cyclohexane] N-oxide proceeds without either regiospecificity or stereospecificity. Eight geometrical isomers of spiro[isoxazolidino[3,2-a]benz-2-Azepine-5,1′-cyclohexane] were formed, of which several were isolated as pure samples. The cycloaddition of dimethyl acetylenedicarboxylate proceeds stereoselectively, leading to spiro[isoxazolino[3,2-a]benz-2-Azepine-5,1′-cyclohexane] with cis arrangement of the protons at C(7) and C(11b)
