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Vyacheslav Ya. Sosnovskikh - One of the best experts on this subject based on the ideXlab platform.
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highly regio and stereoselective addition of aminoenones to 2 substituted 3 nitro 2h Chromenes unexpected synthesis of 5 trifluoromethyl 5h chromeno 3 4 b pyridines
Tetrahedron, 2015Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Igor B Kutyashev, Ivan V Kotovich, Marina A Ezhikova, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 2-R-3-nitro-2H-Chromenes (R=CF3, CCl3, Ph) with aminoenones derived from acetylacetone and cyclic amines (morpholine, piperidine) proceed diastereoselectively to give mainly cis–trans-2,3,4-trisubstituted chromanes as a result of nucleophilic addition of the vinylogous β-methyl group at the C-4 atom of the chromene system. From these compounds, under acidic conditions, 4-acetoacetonyl-3-nitrochromanes and 5H-chromeno[3,4-b]pyridines, depending on the substituent at the 2-position, were obtained in moderate to good yields. Similar results, except for the synthesis of 5H-chromeno[3,4-b]pyridines, were obtained by replacing acetylacetone with benzoylacetone. The stereochemistry of the products was established by X-ray diffraction analysis.
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synthesis of chromeno 3 4 c 1 2 oxazine n oxides via formal 4 2 cycloaddition of 3 nitro 2 trihalomethyl 2h Chromenes with cyclohexanone and pinacolone enamines
Tetrahedron, 2014Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Evgeniya G Matochkina, Vyacheslav Ya. SosnovskikhAbstract:Abstract 3-Nitro-2-trichloro(trifluoro)methyl-2H-Chromenes undergo a formal [4+2] cycloaddition reaction to cyclohexanone and pinacolone enamines, producing chromeno[3,4-c][1,2]benzoxazin-6-oxides with high diastereoselectivity and in good yields. In addition, some novel 2,3,4-trisubstituted chromanes were obtained. The stereochemistry of the products was established based on a 2D NOESY experiment and an X-ray diffraction study.
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highly diastereoselective 1 3 dipolar cycloaddition of nonstabilized azomethine ylides to 3 nitro 2 trihalomethyl 2h Chromenes synthesis of 1 benzopyrano 3 4 c pyrrolidines
ChemInform, 2014Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Evgeniya G Matochkina, Vladimir S Moshkin, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 3-nitro-2-trifluoro(trichloro)methyl-2H-Chromenes, including 2-unsubstituted derivatives, with N-alkyl-a-amino acids (sarcosine, proline) and paraformaldehyde proceed diastereoselectively to give 1-benzopyrano[3,4-c]pyrrolidines in good yields as a result of a 1,3-dipolar cycloaddition of the intermediate nonstabilized azomethine ylide at the D 3 -bond of the chromene system.
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synthesis of 5 trifluoromethyl 5h chromeno 3 4 b pyridines from 3 nitro 2 trifluoromethyl 2h Chromenes and aminoenones derived from acetylacetone and cyclic amines
Tetrahedron Letters, 2013Co-Authors: Vladislav Yu Korotaev, Alexey Yu Barkov, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 3-nitro-2H-Chromenes with aminoenones derived from acetylacetone and cyclic amines proceed diastereoselectively to give functionalized 2,3,4-trisubstituted chromanes as a result of nucleophilic addition of the vinylogous b-methyl group at the C-4 atom of the chromene system. From these compounds, under acidic conditions, 5-(trifluoromethyl)-5H-chromeno[3,4-b]pyridines and 4-acetoacetonyl-3-nitro-2-(trichloromethyl/phenyl)chromanes, depending on the substituent at the 2-position, were obtained in moderate to good yields.
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the first synthesis of 4 unsubstituted 3 trifluoroacetyl coumarins by the knoevenagel condensation of salicylaldehydes with ethyl trifluoroaceto acetate followed by chromene coumarin recyclization
Synlett, 2008Co-Authors: Dmitrii L Chizhov, Marina V Pryadeina, Vyacheslav Ya. Sosnovskikh, Yanina V Burgart, Viktor I. Saloutin, Valery N. CharushinAbstract:A series of ethyl 6-substituted 2-hydroxy-2-(trifluoro-methyl)-2 H-chromene-3-carboxylates was obtained in good yields via the Knoevenagel condensation of salicylaldehydes with ethyl trifluoroacetoacetate in the presence of piperidinium acetate. The subsequent recyclization of these Chromenes proceeds smoothly in refluxing chlorobenzene in the presence of P-toluenesulfonic acid affording previously unknown 3-(trifluoroacetyl)coumarins in moderate to good yields.
Vladislav Yu Korotaev - One of the best experts on this subject based on the ideXlab platform.
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highly regio and stereoselective addition of aminoenones to 2 substituted 3 nitro 2h Chromenes unexpected synthesis of 5 trifluoromethyl 5h chromeno 3 4 b pyridines
Tetrahedron, 2015Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Igor B Kutyashev, Ivan V Kotovich, Marina A Ezhikova, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 2-R-3-nitro-2H-Chromenes (R=CF3, CCl3, Ph) with aminoenones derived from acetylacetone and cyclic amines (morpholine, piperidine) proceed diastereoselectively to give mainly cis–trans-2,3,4-trisubstituted chromanes as a result of nucleophilic addition of the vinylogous β-methyl group at the C-4 atom of the chromene system. From these compounds, under acidic conditions, 4-acetoacetonyl-3-nitrochromanes and 5H-chromeno[3,4-b]pyridines, depending on the substituent at the 2-position, were obtained in moderate to good yields. Similar results, except for the synthesis of 5H-chromeno[3,4-b]pyridines, were obtained by replacing acetylacetone with benzoylacetone. The stereochemistry of the products was established by X-ray diffraction analysis.
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synthesis of chromeno 3 4 c 1 2 oxazine n oxides via formal 4 2 cycloaddition of 3 nitro 2 trihalomethyl 2h Chromenes with cyclohexanone and pinacolone enamines
Tetrahedron, 2014Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Evgeniya G Matochkina, Vyacheslav Ya. SosnovskikhAbstract:Abstract 3-Nitro-2-trichloro(trifluoro)methyl-2H-Chromenes undergo a formal [4+2] cycloaddition reaction to cyclohexanone and pinacolone enamines, producing chromeno[3,4-c][1,2]benzoxazin-6-oxides with high diastereoselectivity and in good yields. In addition, some novel 2,3,4-trisubstituted chromanes were obtained. The stereochemistry of the products was established based on a 2D NOESY experiment and an X-ray diffraction study.
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highly diastereoselective 1 3 dipolar cycloaddition of nonstabilized azomethine ylides to 3 nitro 2 trihalomethyl 2h Chromenes synthesis of 1 benzopyrano 3 4 c pyrrolidines
ChemInform, 2014Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Evgeniya G Matochkina, Vladimir S Moshkin, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 3-nitro-2-trifluoro(trichloro)methyl-2H-Chromenes, including 2-unsubstituted derivatives, with N-alkyl-a-amino acids (sarcosine, proline) and paraformaldehyde proceed diastereoselectively to give 1-benzopyrano[3,4-c]pyrrolidines in good yields as a result of a 1,3-dipolar cycloaddition of the intermediate nonstabilized azomethine ylide at the D 3 -bond of the chromene system.
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synthesis of 5 trifluoromethyl 5h chromeno 3 4 b pyridines from 3 nitro 2 trifluoromethyl 2h Chromenes and aminoenones derived from acetylacetone and cyclic amines
Tetrahedron Letters, 2013Co-Authors: Vladislav Yu Korotaev, Alexey Yu Barkov, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 3-nitro-2H-Chromenes with aminoenones derived from acetylacetone and cyclic amines proceed diastereoselectively to give functionalized 2,3,4-trisubstituted chromanes as a result of nucleophilic addition of the vinylogous b-methyl group at the C-4 atom of the chromene system. From these compounds, under acidic conditions, 5-(trifluoromethyl)-5H-chromeno[3,4-b]pyridines and 4-acetoacetonyl-3-nitro-2-(trichloromethyl/phenyl)chromanes, depending on the substituent at the 2-position, were obtained in moderate to good yields.
William D. Wulff - One of the best experts on this subject based on the ideXlab platform.
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Catalytic Synthesis of 2H-Chromenes
ACS Catalysis, 2015Co-Authors: Nilanjana Majumdar, Nanda D. Paul, Sutanuva Mandal, Bas De Bruin, William D. WulffAbstract:2H-Chromenes (2H-1-benzopyran derivatives) display a broad spectrum of biological activities. The 2H-chromene substructure is an important structural motif present in a variety of medicines, natural products, and materials showing unique photophysical properties. Hence, the structural importance of the benzopyran moiety has elicited a great deal of interest in the field of organic synthesis and chemical biology to develop new and improved synthesis of these molecular skeletons. This review gives an up-to-date overview of different catalytic methodologies developed for the synthesis of 2H-Chromenes and is structured around the three main approaches applied in catalytic 2H-chromene synthesis: (I) catalysis with (transition) metals, (II) metal-free Bronsted and Lewis acid/base catalysis, which includes examples of nonenantioselective organocatalysis, and (III) enantioselective organo-catalysis. The section in which the metal-catalyzed reactions are discussed describes different ring-closing strategies based ...
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simultaneous synthesis of both rings of Chromenes via a benzannulation o quinone methide formation electrocyclization cascade
ChemInform, 2012Co-Authors: Nilanjana Majumdar, Keith A. Korthals, William D. WulffAbstract:The reaction of an α,β-unsaturated Fischer carbene complex of chromium with a propargyl ether bearing an alkenyl group on the propargylic carbon affords the desired Chromenes, including chromene (IIIg), which is transformed to vitamin E (IV).
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Simultaneous Synthesis of Both Rings of Chromenes via a Benzannulation/o-Quinone Methide Formation/Electrocyclization Cascade.
ChemInform, 2012Co-Authors: Nilanjana Majumdar, Keith A. Korthals, William D. WulffAbstract:The reaction of an α,β-unsaturated Fischer carbene complex of chromium with a propargyl ether bearing an alkenyl group on the propargylic carbon affords the desired Chromenes, including chromene (IIIg), which is transformed to vitamin E (IV).
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simultaneous synthesis of both rings of Chromenes via a benzannulation o quinone methide formation electrocyclization cascade
Journal of the American Chemical Society, 2012Co-Authors: Nilanjana Majumdar, Keith A. Korthals, William D. WulffAbstract:A new route to the chromene ring system has been developed which involves the reaction of an α,β-unsaturated Fischer carbene complex of chromium with a propargyl ether bearing an alkenyl group on the propargylic carbon. This transformation involves a cascade of reactions that begins with a benzannulation reaction and is followed by the formation of an o-quinone methide, and finally results in the emergence of a chromene upon an electrocyclization. This reaction was extended to provide access by employing an aryl carbene complex. This constitutes the first synthesis of Chromenes in which both rings of the chromene system are generated in a single step and is highlighted in the synthesis of lapachenole and vitamin E.
Alexey Yu Barkov - One of the best experts on this subject based on the ideXlab platform.
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highly regio and stereoselective addition of aminoenones to 2 substituted 3 nitro 2h Chromenes unexpected synthesis of 5 trifluoromethyl 5h chromeno 3 4 b pyridines
Tetrahedron, 2015Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Igor B Kutyashev, Ivan V Kotovich, Marina A Ezhikova, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 2-R-3-nitro-2H-Chromenes (R=CF3, CCl3, Ph) with aminoenones derived from acetylacetone and cyclic amines (morpholine, piperidine) proceed diastereoselectively to give mainly cis–trans-2,3,4-trisubstituted chromanes as a result of nucleophilic addition of the vinylogous β-methyl group at the C-4 atom of the chromene system. From these compounds, under acidic conditions, 4-acetoacetonyl-3-nitrochromanes and 5H-chromeno[3,4-b]pyridines, depending on the substituent at the 2-position, were obtained in moderate to good yields. Similar results, except for the synthesis of 5H-chromeno[3,4-b]pyridines, were obtained by replacing acetylacetone with benzoylacetone. The stereochemistry of the products was established by X-ray diffraction analysis.
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synthesis of chromeno 3 4 c 1 2 oxazine n oxides via formal 4 2 cycloaddition of 3 nitro 2 trihalomethyl 2h Chromenes with cyclohexanone and pinacolone enamines
Tetrahedron, 2014Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Evgeniya G Matochkina, Vyacheslav Ya. SosnovskikhAbstract:Abstract 3-Nitro-2-trichloro(trifluoro)methyl-2H-Chromenes undergo a formal [4+2] cycloaddition reaction to cyclohexanone and pinacolone enamines, producing chromeno[3,4-c][1,2]benzoxazin-6-oxides with high diastereoselectivity and in good yields. In addition, some novel 2,3,4-trisubstituted chromanes were obtained. The stereochemistry of the products was established based on a 2D NOESY experiment and an X-ray diffraction study.
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highly diastereoselective 1 3 dipolar cycloaddition of nonstabilized azomethine ylides to 3 nitro 2 trihalomethyl 2h Chromenes synthesis of 1 benzopyrano 3 4 c pyrrolidines
ChemInform, 2014Co-Authors: Vladislav Yu Korotaev, Mikhail I Kodess, Alexey Yu Barkov, Evgeniya G Matochkina, Vladimir S Moshkin, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 3-nitro-2-trifluoro(trichloro)methyl-2H-Chromenes, including 2-unsubstituted derivatives, with N-alkyl-a-amino acids (sarcosine, proline) and paraformaldehyde proceed diastereoselectively to give 1-benzopyrano[3,4-c]pyrrolidines in good yields as a result of a 1,3-dipolar cycloaddition of the intermediate nonstabilized azomethine ylide at the D 3 -bond of the chromene system.
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synthesis of 5 trifluoromethyl 5h chromeno 3 4 b pyridines from 3 nitro 2 trifluoromethyl 2h Chromenes and aminoenones derived from acetylacetone and cyclic amines
Tetrahedron Letters, 2013Co-Authors: Vladislav Yu Korotaev, Alexey Yu Barkov, Vyacheslav Ya. SosnovskikhAbstract:Reactions of 3-nitro-2H-Chromenes with aminoenones derived from acetylacetone and cyclic amines proceed diastereoselectively to give functionalized 2,3,4-trisubstituted chromanes as a result of nucleophilic addition of the vinylogous b-methyl group at the C-4 atom of the chromene system. From these compounds, under acidic conditions, 5-(trifluoromethyl)-5H-chromeno[3,4-b]pyridines and 4-acetoacetonyl-3-nitro-2-(trichloromethyl/phenyl)chromanes, depending on the substituent at the 2-position, were obtained in moderate to good yields.
Nilanjana Majumdar - One of the best experts on this subject based on the ideXlab platform.
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Catalytic Synthesis of 2H-Chromenes
ACS Catalysis, 2015Co-Authors: Nilanjana Majumdar, Nanda D. Paul, Sutanuva Mandal, Bas De Bruin, William D. WulffAbstract:2H-Chromenes (2H-1-benzopyran derivatives) display a broad spectrum of biological activities. The 2H-chromene substructure is an important structural motif present in a variety of medicines, natural products, and materials showing unique photophysical properties. Hence, the structural importance of the benzopyran moiety has elicited a great deal of interest in the field of organic synthesis and chemical biology to develop new and improved synthesis of these molecular skeletons. This review gives an up-to-date overview of different catalytic methodologies developed for the synthesis of 2H-Chromenes and is structured around the three main approaches applied in catalytic 2H-chromene synthesis: (I) catalysis with (transition) metals, (II) metal-free Bronsted and Lewis acid/base catalysis, which includes examples of nonenantioselective organocatalysis, and (III) enantioselective organo-catalysis. The section in which the metal-catalyzed reactions are discussed describes different ring-closing strategies based ...
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simultaneous synthesis of both rings of Chromenes via a benzannulation o quinone methide formation electrocyclization cascade
ChemInform, 2012Co-Authors: Nilanjana Majumdar, Keith A. Korthals, William D. WulffAbstract:The reaction of an α,β-unsaturated Fischer carbene complex of chromium with a propargyl ether bearing an alkenyl group on the propargylic carbon affords the desired Chromenes, including chromene (IIIg), which is transformed to vitamin E (IV).
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Simultaneous Synthesis of Both Rings of Chromenes via a Benzannulation/o-Quinone Methide Formation/Electrocyclization Cascade.
ChemInform, 2012Co-Authors: Nilanjana Majumdar, Keith A. Korthals, William D. WulffAbstract:The reaction of an α,β-unsaturated Fischer carbene complex of chromium with a propargyl ether bearing an alkenyl group on the propargylic carbon affords the desired Chromenes, including chromene (IIIg), which is transformed to vitamin E (IV).
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simultaneous synthesis of both rings of Chromenes via a benzannulation o quinone methide formation electrocyclization cascade
Journal of the American Chemical Society, 2012Co-Authors: Nilanjana Majumdar, Keith A. Korthals, William D. WulffAbstract:A new route to the chromene ring system has been developed which involves the reaction of an α,β-unsaturated Fischer carbene complex of chromium with a propargyl ether bearing an alkenyl group on the propargylic carbon. This transformation involves a cascade of reactions that begins with a benzannulation reaction and is followed by the formation of an o-quinone methide, and finally results in the emergence of a chromene upon an electrocyclization. This reaction was extended to provide access by employing an aryl carbene complex. This constitutes the first synthesis of Chromenes in which both rings of the chromene system are generated in a single step and is highlighted in the synthesis of lapachenole and vitamin E.