caa a22 4500 475762029 CHVBK 20180406123554.0 cr unu---uuuuu 170329e20000201xx s 000 0 eng 10.1007/BF02494688 doi (NATIONALLICENCE)springer-10.1007/BF02494688 [4+2]-Cycloaddition of 3,6-bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5-tetrazines with alkenes [Elektronische Daten] [G. Rusinov, R. Ishmetova, N. Latosh, I. Ganebnych, O. Chupakhin, V. Potemkin] A number of 1,4-dihydropyridazines and pyridazines were prepared by the Diels-Alder reaction with an inverse electron demand from cyclic heterodiene systems, 3,6-bis(3,5-dimethyl-4-R-pyrazol-1-yl)-1,2,4,5-tetrazines, and some enamines as well as from 4-vinylpyridine, butyl vinyl ether, phenylacetylene, and acrylamide. The reaction of 3,6-bis(3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazine with styrene afforded 4,5-dihydropyridazine, which was readily oxidized by atmospheric oxygen to form the corresponding pyridazine. Electron-withdrawing substituents (Br or Cl) in the pyrazole rings accelerate [4+2]-cycloaddition. When heated, 1,4-dihydropyridazines, which were synthesized from tetrazines and enamines, eliminated amine to give pyridazines. The reactivities of tetrazines were evaluated by quantum-chemical methods. Kluwer Academic/Plenum Publishers, 2000 1,2,4,5-tetrazine nationallicence 1,4-dihydropyridazine nationallicence pyridazine nationallicence enamine nationallicence Carboni-Lindsey reaction nationallicence [4+2]-cycloaddition nationallicence azadiene nationallicence dienophile nationallicence quantum-chemical calculations nationallicence Rusinov G. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut Ishmetova R. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut Latosh N. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut Ganebnych I. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut Chupakhin O. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut Potemkin V. Chelyabinsk State University, 129 ul. Br. Kashirinykh, 454136, Chelyabinsk, Russian Federation aut Russian Chemical Bulletin Kluwer Academic Publishers-Plenum Publishers 49/2(2000-02-01), 355-362 1066-5285 49:2<355 2000 49 11172 https://doi.org/10.1007/BF02494688 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02494688 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Rusinov G. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut NATIONALLICENCE 700 1- Ishmetova R. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut NATIONALLICENCE 700 1- Latosh N. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut NATIONALLICENCE 700 1- Ganebnych I. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut NATIONALLICENCE 700 1- Chupakhin O. Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 20 ul. S. Kovalevskoy, 620219, Ekaterinburg, Russian Federation aut NATIONALLICENCE 700 1- Potemkin V. Chelyabinsk State University, 129 ul. Br. Kashirinykh, 454136, Chelyabinsk, Russian Federation aut NATIONALLICENCE 773 0- Russian Chemical Bulletin Kluwer Academic Publishers-Plenum Publishers 49/2(2000-02-01), 355-362 1066-5285 49:2<355 2000 49 11172 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer