Results 281 to 290 of about 26,379 (326)
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Polymers with quinoxaline units. IV. Polymers with quinoxaline and oxazine units
Journal of Polymer Science Part A-1: Polymer Chemistry, 1968AbstractSix ladder or partly ladder polymers have been prepared by the condensation of diaminodiphenols with tetrachloro‐ or terahydroxyquinoxaline derivatives with the use of poly (phosphoric acid), pyridine, and naphthalene as reaction media. The polymers thus obtained are highly colored powdery materials which are slightly soluble in concentrated ...
Masahiko Okada +2 more
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Chemistry, 2018
The gold-catalyzed annulation of diethynyl N-heterocycles for the synthesis of quinoxaline-/phenazine-based pentalenes and the study of their optoelectronic properties are described.
K. Sekine +7 more
semanticscholar +1 more source
The gold-catalyzed annulation of diethynyl N-heterocycles for the synthesis of quinoxaline-/phenazine-based pentalenes and the study of their optoelectronic properties are described.
K. Sekine +7 more
semanticscholar +1 more source
Angewandte Chemie, 2016
A simple method for the preparation of functionalized quinoxalines is reported. Starting from readily accessible ortho-diisocyanoarenes and (perfluoro)alkyl iodides, the quinoxaline core is constructed during (perfluoro)alkylation by atom transfer ...
Dirk Leifert, A. Studer
semanticscholar +1 more source
A simple method for the preparation of functionalized quinoxalines is reported. Starting from readily accessible ortho-diisocyanoarenes and (perfluoro)alkyl iodides, the quinoxaline core is constructed during (perfluoro)alkylation by atom transfer ...
Dirk Leifert, A. Studer
semanticscholar +1 more source
, 2018
Synthesis of quinoxalines from o‐phenylenediamines (o‐PDs) with electronically diversified 1,2‐diketones and α‐bromoketones via simple cyclocondensation reaction using an heterogeneous nano‐ϒ‐Fe2O3‐SO3H catalyst has been reported under solvent free ...
K. B. Harsha +6 more
semanticscholar +1 more source
Synthesis of quinoxalines from o‐phenylenediamines (o‐PDs) with electronically diversified 1,2‐diketones and α‐bromoketones via simple cyclocondensation reaction using an heterogeneous nano‐ϒ‐Fe2O3‐SO3H catalyst has been reported under solvent free ...
K. B. Harsha +6 more
semanticscholar +1 more source
One-Pot Regiospecific Synthesis of Quinoxalines via a CH2-Extrusion Reaction.
Organic Letters, 2016A convenient "one-pot" regiospecific synthesis of substituted quinoxalines from o-phenylenediamines and ynones under metal-free conditions has been developed.
Jinhai Shen +5 more
semanticscholar +1 more source
2016
The synthesis of quinoxalines has been intensively studied in the past, especially because of the diverse biological activities ascribed to many representatives of this class of compounds. Consequently, a large variety of synthetic methods for the synthesis of functionalized quinoxalines have been reported in literature.
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The synthesis of quinoxalines has been intensively studied in the past, especially because of the diverse biological activities ascribed to many representatives of this class of compounds. Consequently, a large variety of synthetic methods for the synthesis of functionalized quinoxalines have been reported in literature.
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, 2018
Owing to the dehydrogenative rearomatization of hydrogenation product and poisoning effect of nitrogen atom, asymmetric hydrogenation of polycyclic nitrogen-containing heteroaromatics is still a great challenge.
Shu Hu +3 more
semanticscholar +1 more source
Owing to the dehydrogenative rearomatization of hydrogenation product and poisoning effect of nitrogen atom, asymmetric hydrogenation of polycyclic nitrogen-containing heteroaromatics is still a great challenge.
Shu Hu +3 more
semanticscholar +1 more source
Organic Letters, 2016
A copper-catalyzed cycloamination of α-Csp(3)-H bond of N-aryl ketimines with sodium azide has been developed. This methodology provides an efficient access to quinoxalines and features mild reaction conditions and readily available ketimines with ...
Tengfei Chen +5 more
semanticscholar +1 more source
A copper-catalyzed cycloamination of α-Csp(3)-H bond of N-aryl ketimines with sodium azide has been developed. This methodology provides an efficient access to quinoxalines and features mild reaction conditions and readily available ketimines with ...
Tengfei Chen +5 more
semanticscholar +1 more source
Journal of Organic Chemistry, 2017
A practical and concise protocol for the efficient preparation of pyrrolo[1,2-a]quinoxalines through a cascade of alcohol oxidation/imine formation/intramolecular cyclization/oxidative dehydrogenation has been established. A series of substituted pyrrolo[
Jixing Li +4 more
semanticscholar +1 more source
A practical and concise protocol for the efficient preparation of pyrrolo[1,2-a]quinoxalines through a cascade of alcohol oxidation/imine formation/intramolecular cyclization/oxidative dehydrogenation has been established. A series of substituted pyrrolo[
Jixing Li +4 more
semanticscholar +1 more source
Tetrahedron, 1964
Abstract Base catalysed intramolecular cyclization of α-cyano- o -nitroacetanilides (Ia–d) to the corresponding 2-cyano-3-hydroxyquinoxaline 1-oxides (IIa-d) is described, and a mechanism proposed. The cyanoquinoxaline N-oxides (IIa-d) on reduction are deoxygenated with simultaneous loss of the nitrile group, and when heated with concentrated aqueous
M. S. Habib, Yusuf Ahmad, Ziauddin
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Abstract Base catalysed intramolecular cyclization of α-cyano- o -nitroacetanilides (Ia–d) to the corresponding 2-cyano-3-hydroxyquinoxaline 1-oxides (IIa-d) is described, and a mechanism proposed. The cyanoquinoxaline N-oxides (IIa-d) on reduction are deoxygenated with simultaneous loss of the nitrile group, and when heated with concentrated aqueous
M. S. Habib, Yusuf Ahmad, Ziauddin
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