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Alexander V. Butin - One of the best experts on this subject based on the ideXlab platform.
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furan ring opening indole ring closure Recyclization of 2 2 aminophenyl furans into 2 2 oxoalkyl indoles
Tetrahedron, 2012Co-Authors: Arkady S Pilipenko, Alexander V. Butin, Igor V. Trushkov, Vladimir V Melchin, Dmitry A CheshkovAbstract:The acid-catalyzed rearrangement of 5-alkyl-2-[2-(sulfonylamino)phenyl]furans into 2-(2-oxoalkyl)indoles is described. When the N-sulfonyl group in the starting compounds was displaced by an N-acyl group, the corresponding indoles were not formed under the same reaction conditions due to the in situ indole deacylation and decomposition. The presence of an alkyl group at the C5 position of the furan ring is also crucial for the efficiency of the process. The discussed rearrangement provides a simple and efficient approach to 2-(2-oxoalkyl)indoles.
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Recyclization of furan in the synthesis of pyrrolo 1 2 d 1 4 diazepinone
Chemistry of Heterocyclic Compounds, 2011Co-Authors: Vitaly A Shcherbinin, Tatyana A Nevolina, Alexander V. ButinAbstract:Pyrrolodiazepines are an important class of heterocyclic compounds due to their broad spectrum of pharmacological activity [1-4]. Additionally, the pyrrolodiazepinone framework is the basic structural fragment of natural anthramycin alkaloids which show antitumor activity [5]. All of this is responsible for the high interest in developing synthetic methods for these compounds. However, the Paal-Knorr reaction has been virtually unused in the preparation of pyrrolodiazepinones. Only two examples of its use have been reported. The first involves successive closing of the pyrrole and diazepinone rings [6] and the second a simultaneous formation of both rings [7]. This is likely associated with the fact that the synthesis of suitable 1,4-dicarbonyl compounds as precursors of the pyrrolodiazepinones is a multistage and laborious process [7]. It is well known that furan derivatives in the presence of acids can serve as precursors of 1,4-diketones [8]. This property of furan compounds allowed us to develop a simple and efficient method for preparing pyrrolo[1,2-a][1,4]diazepinones based on the Recyclization of N-(furfuryl)anthranilamides [9]. This process is a one-pot domino reaction in which opening of the furan ring and the formation of the diazepinone and pyrroles ring occur. We now report the use of this methodology for preparing pyrrolo[1,2-d][1,4]diazepinones. Acylation of the furylethylamine 1 by the 2-phthalimidoacetyl chloride 2 in benzene gave amide 3, treatment of which with hydrazine hydrate in ethanol led to the removal of the phthalimido protection and formation of the amine 4. Holding compound 4 in a mixture of acetic and hydrochloric acids for 1 day at room temperature and subsequent work up of the reaction mixture with an aqueous solution of NaHCO3 gave the target compound 6. Evidently the reaction takes place via intermediate formation of the diketone 5. The yield of the pyrrolodiazepinone 6 is 21% which compares with the results in the study [6]. However, bearing in mind the simplicity of these procedures in our proposed method, it can be used in the preparation of other pyrrolo[1,2-d][1,4]diazepinones and in further work we intend to carry out an optimization of the method. H and C NMR spectra were recorded on a Bruker DPX-300 spectrometer (300 and 75 MHz respectively) using CDCl3 as solvent. The standards used were the residual protons of the deuterated solvent CDCl3 (7.25 ppm for H and 77.0 ppm for C). Mass spectra were obtained on a Kratos MS-30 spectrometer by EI with ionizing energy 70 eV and ionization chamber temperature 200oC.
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Recyclization of (2-Aminophenyl)bis(5-tert-butyl-2-furyl)methanes into Indole Derivatives:Unusual Dependence on Substituent at Nitrogen Atom
Synthesis, 2008Co-Authors: Alexander V. Butin, Sergey K. Smirnov, Fatima A. Tsiunchik, Maxim G. Uchuskin, Igor V. TrushkovAbstract:The Recyclization of (2-aminophenyl)bis(5-tert-butyl-2-furyl)methanes under acidic conditions was studied. It was found that the extent of reaction of these substrates depends on the substituent at the nitrogen atom of the aniline moiety. N-Tosyl derivatives were converted into the corresponding 3-(5-tert-butyl-2-furyl)-2-(4,4-dimethyl-3-oxopentyl)-l-tosyl- 1H -indoles. Indole formation was followed by furan ring opening in the case of N-unsubstituted substrates leading to 3-(5,5-dimethyl-1,4-dioxohexyl)-2-(4,4-dimethyl-3-oxopentyl)- 1H-indoles. The same products were obtained from N-acetyl derivatives. However, the behavior of the N-benzoyl analogues depends on the reaction conditions: at room temperature 1-benzoyl-3-(5-tert-butyl-2-furyl)-1H-indoles were formed, but debenzoylation and furan ring opening proceed with heating. These data and results of control experiments showed that the reaction mechanism consists of three successive steps: Recyclization itself, deacylation of the resulting N-acylindole, and furan ring opening in N-unsubstituted 3-(2-furyl)indoles. The last step can be realized for N-unsubstituted indoles only, but the furan ring is stable for N-acylindoles. This was explained by transformation of N-unsubstituted 1H-indoles under the reaction conditions into 3H-indole tautomers. These tautomers can be considered as 2,5-dialkylfurans, which have much lower stability against acids than 2-aryl-5-alkylfurans. This tautomerization is impossible for N-acylindoles. The high acidic stability of 2-(5-tert-butyl-2-furyl)indoles supports this conclusion.
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a furan Recyclization reaction as a new approach to isochromenes
Synthesis, 2008Co-Authors: Alexander V. Butin, Artem S Dmitriev, Vladimir T Abaev, Vladimir V Melchin, Arkady S Pilipenko, Alexander S ShashkovAbstract:As part of our ongoing interest in the synthesis of benz-annelated heterocycles from O-substituted benzylfurans, Recyclization of [ O-(hydroxymethyl)aryl]difurylmethanes was studied. It was shown that, under acidic conditions, the O-hydroxymethyl group in these compounds acts as a nucleophile and tetracyclic isochromene derivatives are formed via a Recyclization-cyclization tandem sequence. Alternatively, these compounds can be synthesized by reduction of the corresponding isochromone derivatives with lithium aluminum hydride. The potent biologically active analogues of cannabinoids were also obtained by interaction of isochromone derivatives with excess of methylmagnesium iodide.
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the effect of an n substituent on the Recyclization of 2 aminoaryl bis 5 tert butyl 2 furyl methanes synthesis of 3 furylindoles and triketoindoles
Tetrahedron Letters, 2008Co-Authors: Alexander V. Butin, Sergey K. Smirnov, Igor V. TrushkovAbstract:Abstract The Recyclization of (2-aminophenyl)bis(5- tert -butyl-2-furyl)methane derivatives has been studied. It was shown that the acid-catalyzed Recyclization of N -tosylamides leads to the formation of 2-(3-oxoalkyl)-3-(2-furyl)indoles. In contrast, under the same reaction conditions, acetamides are transformed into indoles containing three keto groups. The acid-catalyzed removal of the acetyl group from these substrates facilitated protolytic furan ring opening. The same triketones can be directly obtained from (2-aminoaryl)bis(5- tert -butyl-2-furyl)methanes.
Igor V. Trushkov - One of the best experts on this subject based on the ideXlab platform.
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furan ring opening indole ring closure Recyclization of 2 2 aminophenyl furans into 2 2 oxoalkyl indoles
Tetrahedron, 2012Co-Authors: Arkady S Pilipenko, Alexander V. Butin, Igor V. Trushkov, Vladimir V Melchin, Dmitry A CheshkovAbstract:The acid-catalyzed rearrangement of 5-alkyl-2-[2-(sulfonylamino)phenyl]furans into 2-(2-oxoalkyl)indoles is described. When the N-sulfonyl group in the starting compounds was displaced by an N-acyl group, the corresponding indoles were not formed under the same reaction conditions due to the in situ indole deacylation and decomposition. The presence of an alkyl group at the C5 position of the furan ring is also crucial for the efficiency of the process. The discussed rearrangement provides a simple and efficient approach to 2-(2-oxoalkyl)indoles.
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Recyclization of (2-Aminophenyl)bis(5-tert-butyl-2-furyl)methanes into Indole Derivatives:Unusual Dependence on Substituent at Nitrogen Atom
Synthesis, 2008Co-Authors: Alexander V. Butin, Sergey K. Smirnov, Fatima A. Tsiunchik, Maxim G. Uchuskin, Igor V. TrushkovAbstract:The Recyclization of (2-aminophenyl)bis(5-tert-butyl-2-furyl)methanes under acidic conditions was studied. It was found that the extent of reaction of these substrates depends on the substituent at the nitrogen atom of the aniline moiety. N-Tosyl derivatives were converted into the corresponding 3-(5-tert-butyl-2-furyl)-2-(4,4-dimethyl-3-oxopentyl)-l-tosyl- 1H -indoles. Indole formation was followed by furan ring opening in the case of N-unsubstituted substrates leading to 3-(5,5-dimethyl-1,4-dioxohexyl)-2-(4,4-dimethyl-3-oxopentyl)- 1H-indoles. The same products were obtained from N-acetyl derivatives. However, the behavior of the N-benzoyl analogues depends on the reaction conditions: at room temperature 1-benzoyl-3-(5-tert-butyl-2-furyl)-1H-indoles were formed, but debenzoylation and furan ring opening proceed with heating. These data and results of control experiments showed that the reaction mechanism consists of three successive steps: Recyclization itself, deacylation of the resulting N-acylindole, and furan ring opening in N-unsubstituted 3-(2-furyl)indoles. The last step can be realized for N-unsubstituted indoles only, but the furan ring is stable for N-acylindoles. This was explained by transformation of N-unsubstituted 1H-indoles under the reaction conditions into 3H-indole tautomers. These tautomers can be considered as 2,5-dialkylfurans, which have much lower stability against acids than 2-aryl-5-alkylfurans. This tautomerization is impossible for N-acylindoles. The high acidic stability of 2-(5-tert-butyl-2-furyl)indoles supports this conclusion.
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the effect of an n substituent on the Recyclization of 2 aminoaryl bis 5 tert butyl 2 furyl methanes synthesis of 3 furylindoles and triketoindoles
Tetrahedron Letters, 2008Co-Authors: Alexander V. Butin, Sergey K. Smirnov, Igor V. TrushkovAbstract:Abstract The Recyclization of (2-aminophenyl)bis(5- tert -butyl-2-furyl)methane derivatives has been studied. It was shown that the acid-catalyzed Recyclization of N -tosylamides leads to the formation of 2-(3-oxoalkyl)-3-(2-furyl)indoles. In contrast, under the same reaction conditions, acetamides are transformed into indoles containing three keto groups. The acid-catalyzed removal of the acetyl group from these substrates facilitated protolytic furan ring opening. The same triketones can be directly obtained from (2-aminoaryl)bis(5- tert -butyl-2-furyl)methanes.
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synthesis of the 4 10 dihydro 3h pyridazino 1 6 b isoquinolin 10 one system by a furan Recyclization reaction
Synthesis, 2007Co-Authors: Alexander V. Butin, Artem S Dmitriev, Olga N Kostyukova, Vladimir T Abaev, Igor V. TrushkovAbstract:The novel 4,10-dihydro-3 H-pyridazino[1,6- B]isoquinolin-10-one heterocyclic system was synthesized by acid-catalyzed Recyclization of 2-(difurylmethyl)benzohydrazides as well as by Recyclization of (2-carboxyaryl)difurylmethanes to isocoumarins followed by the reaction with hydrazine hydrate.
Dewen Dong - One of the best experts on this subject based on the ideXlab platform.
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synthesis of multi substituted 4 aminopyridines via ring opening and Recyclization reactions of 2 iminopyridines
RSC Advances, 2014Co-Authors: Fenguo Zhou, Ning Zhang, Xun Zhang, Yongjiu Liang, Rui Zhang, Dewen DongAbstract:A novel synthesis of multi-substituted 4-aminopyridines from 2-iminopyridines by a two-step procedure is described. During this transformation, 4-amino-2-iminopyridines undergo a regioselective ring-opening reaction in the presence of KOH in t-butanol to afford 5-oxo-pent-3-enimidamides, which are then converted into 4-aminopyridines in toluene under reflux following a 6π-azaelectrocyclization and N-to-N 1,3-sulfonyl group migration mechanism.
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regiospecific β lactam ring opening Recyclization reactions of n aryl 3 spirocyclic β lactams catalyzed by a lewis bronsted acids combined superacid catalyst system a new entry to 3 spirocyclicquinolin 4 1h ones
Chemical Communications, 2012Co-Authors: Yinqiao Hu, Xiaolan Fu, Badrudeen Barry, Xihe Bi, Dewen DongAbstract:The regiospecific β-lactam ring-opening/Recyclization reaction of N-aryl-3-spirocyclic-β-lactams, made by the one-pot cyclization reaction of acetoacetanilides, has been achieved for the first time using a Lewis–Bronsted acids combined superacid catalyst system, thus providing an efficient entry to 3-spirocyclicquinolin-4(1H)-ones. A mechanism involving superacid-catalysis was proposed.
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ring opening Recyclization reactions of dimethylamino propenoyl substituted cyclopropanes facile synthesis of halogenated pyridin 2 1h ones
Synthesis, 2009Co-Authors: Rui Zhang, Yongjiu Liang, Yang Zhou, Zijiang Jiang, Dewen DongAbstract:A facile and efficient synthesis Of Substituted pyridin-2(1H)-ones has been developed by the reaction of readily available 1-carbamoyl-]-[3-(dimethylamino)propenoyl]cyclopropanes with phosphoryl chloride or phosphorus tribromide in dichloromethane at room temperature.
Qun Liu - One of the best experts on this subject based on the ideXlab platform.
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DABCO-catalyzed ring opening of activated cyclopropanes and Recyclization leading to γ-lactams with an all-carbon quaternary center
Chemical Communications, 2014Co-Authors: Shaoxia Lin, Fushun Liang, Ling Li, Qun LiuAbstract:A novel and efficient method for the construction of γ-lactams with an all-carbon quaternary center is developed via a DABCO-catalyzed reaction of EWG-activated cyclopropanecarboxamides and electron-deficient alkenes. The process involves sequential ring-opening of activated cyclopropanes, intermolecular Michael addition and intramolecular aza-cyclization.
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Domino ring-opening/Recyclization reactions of doubly activated cyclopropanes as a strategy for the synthesis of furoquinoline derivatives
Angewandte Chemie - International Edition, 2007Co-Authors: Zhiguo Zhang, Shao Guang Sun, Tao Xiong, Qian Zhang, Qun LiuAbstract:In one easy step, doubly activated cyclopropanes 1 can be transformed into furoquinoline derivatives 2 through a tandem ring-opening/Recyclization reaction mediated by SnCl4⋅5 H2O. A variety of substrates 1 derived from cheap starting materials were converted into the corresponding furoquinolines in good to excellent yields with high chemo- and regioselectivity. R=H, Me, OMe, Cl, or aromatic group is naphthyl
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A new efficient synthesis of pyranoquinolines from 1-acetyl N-aryl cyclopentanecarboxamides
Organic Letters, 2007Co-Authors: Qian Zhang, Zihong Yan, Qun Liu, Zhiguo Zhang, Tunyu WangAbstract:A new efficient synthesis of pyrano[2,3-b]quinoline derivatives is developed via the H2SO4-mediated tandem cyclization/ring-opening/Recyclization reaction of readily available 1-acetyl N-aryl cyclopentanecarboxamides, during which a novel ring-cleavage fashion of the cyclopentane unit is involved and possible mechanisms are discussed.
Fushun Liang - One of the best experts on this subject based on the ideXlab platform.
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dabco catalyzed ring opening of activated cyclopropanes and Recyclization leading to γ lactams with an all carbon quaternary center
ChemInform, 2015Co-Authors: Ling Li, Fushun LiangAbstract:A new and efficient organocatalyzed strategy for the synthesis of γ-lactams with an all-carbon quaternary center is developed.
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dabco catalyzed ring opening of activated cyclopropanes and Recyclization leading to γ lactams with an all carbon quaternary center
Chemical Communications, 2014Co-Authors: Ling Li, Fushun LiangAbstract:A novel and efficient method for the construction of γ-lactams with an all-carbon quaternary center is developed via a DABCO-catalyzed reaction of EWG-activated cyclopropanecarboxamides and electron-deficient alkenes. The process involves sequential ring-opening of activated cyclopropanes, intermolecular Michael addition and intramolecular aza-cyclization.
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DABCO-catalyzed ring opening of activated cyclopropanes and Recyclization leading to γ-lactams with an all-carbon quaternary center
Chemical Communications, 2014Co-Authors: Shaoxia Lin, Fushun Liang, Ling Li, Qun LiuAbstract:A novel and efficient method for the construction of γ-lactams with an all-carbon quaternary center is developed via a DABCO-catalyzed reaction of EWG-activated cyclopropanecarboxamides and electron-deficient alkenes. The process involves sequential ring-opening of activated cyclopropanes, intermolecular Michael addition and intramolecular aza-cyclization.
