2H-3,l-Pyrazolo[3,4-e]oxazines (5a-c) and tacrine analogies (6a-c) were designed and prepared using 5-amino-4-cyanopyrazole (7) and cycloketones (2a-c) as reactants. The study demonstrated that the new conversion exis...2H-3,l-Pyrazolo[3,4-e]oxazines (5a-c) and tacrine analogies (6a-c) were designed and prepared using 5-amino-4-cyanopyrazole (7) and cycloketones (2a-c) as reactants. The study demonstrated that the new conversion existed in the Friedlander reaction of o-aminocyanopyrazole with cycloketones. (C) 2007 Jia Rong Li. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
The novel spirooxindoline fused [1,3]oxazines were efficiently synthesized from Diels-Alder reaction of N-arylmaleimides with 1,2-dihydro-2-oxospiro[3H-indole-3,2＇-[2H,9aH-pyrido[2,1-b][l,3]oxazines], which were gene...The novel spirooxindoline fused [1,3]oxazines were efficiently synthesized from Diels-Alder reaction of N-arylmaleimides with 1,2-dihydro-2-oxospiro[3H-indole-3,2＇-[2H,9aH-pyrido[2,1-b][l,3]oxazines], which were generated in situ from three-component reactions of substituted pyridines and isatins with methyl propiolate, or di- methyl acetylenedicarboxylate. The stereochemistry of the products was clearly clarified by the analysis of 1H NMR data and single crystal structures of the obtained polycyclic compounds.展开更多
Caffeine was applied as a green and natural catalyst for the one-pot,four-component sequential condensation between 2-hydroxy-1,4-naphthoquinone,aromatic 1,2-diamines,ammonium thiocyanate and acid chlorides in the pre...Caffeine was applied as a green and natural catalyst for the one-pot,four-component sequential condensation between 2-hydroxy-1,4-naphthoquinone,aromatic 1,2-diamines,ammonium thiocyanate and acid chlorides in the presence of a basic ionic liquid（l-butyl-3-methylimidazolium hydroxide） to afford the corresponding benzo[a][1,3]oxazino[6,5-c]phenazine derivatives.In this one-pot transformation,five bonds and two new rings are efficiently formed.This protocol has the advantages of operational simplicity,high yields,easy workup,avoidance of hazardous or toxic catalysts and organic solvents and high chemo-and regioselectivities.展开更多
文摘2H-3,l-Pyrazolo[3,4-e]oxazines (5a-c) and tacrine analogies (6a-c) were designed and prepared using 5-amino-4-cyanopyrazole (7) and cycloketones (2a-c) as reactants. The study demonstrated that the new conversion existed in the Friedlander reaction of o-aminocyanopyrazole with cycloketones. (C) 2007 Jia Rong Li. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金This work was financially supported by the National Natural Science Foundation of China （Grant No. 21272200） and the Priority Academic Program Development of Jiangsu Higher Education Institutions. We would also like to express our sincere thanks to the Analysis Center of Yangzhou University for providing all necessary instruments for characterization of structures.
文摘The novel spirooxindoline fused [1,3]oxazines were efficiently synthesized from Diels-Alder reaction of N-arylmaleimides with 1,2-dihydro-2-oxospiro[3H-indole-3,2＇-[2H,9aH-pyrido[2,1-b][l,3]oxazines], which were generated in situ from three-component reactions of substituted pyridines and isatins with methyl propiolate, or di- methyl acetylenedicarboxylate. The stereochemistry of the products was clearly clarified by the analysis of 1H NMR data and single crystal structures of the obtained polycyclic compounds.
基金financial support from the Research Council of Young Researchers and Elite Club,Yazd Branch,Islamic Azad University,Yazd,Iran and University of Science and Arts of Yazd,Iran
文摘Caffeine was applied as a green and natural catalyst for the one-pot,four-component sequential condensation between 2-hydroxy-1,4-naphthoquinone,aromatic 1,2-diamines,ammonium thiocyanate and acid chlorides in the presence of a basic ionic liquid（l-butyl-3-methylimidazolium hydroxide） to afford the corresponding benzo[a][1,3]oxazino[6,5-c]phenazine derivatives.In this one-pot transformation,five bonds and two new rings are efficiently formed.This protocol has the advantages of operational simplicity,high yields,easy workup,avoidance of hazardous or toxic catalysts and organic solvents and high chemo-and regioselectivities.
