Halo-heterocyclization of trans-5-phenyl-3-cinnamylsulfanyl[1,2,4]triazine into [1,3]thiazino[3,2-b][1,2,4]triazin-9-ium systems
摘要:
Treatment of trans-5-phenyl-3-cinnamylsulfanyl[1,2,4]triazine with bromine or iodine in dichloromethane leads to halo-annulation onto the thiazine moiety with formation of (7r,8t)-7-halo-3,8-dipheny1-7,8-dihydro-6H-[1,3]thiazino[3,2-b][1,2,4]-triazin-9-ium salts. The product structure was confirmed by X-ray study.
Intramolecular Diels-Alder reactions of 1,2,4-triazines. Synthesis of 3-alkylpyridines via Raney nickel desulfurization of thieno[2,3-b]pyridines
作者:Maria V. Papadopoulou、Edward C. Taylor
DOI:10.1016/j.tet.2021.132158
日期:2021.6
2-Aryl-2,3-dihydrothieno[2,3-b]pyridines have been prepared via intramolecular Diels-Alderreactions of suitably 3-substituted 1,2,4-triazine intermediates, followed by their reductive desulfurization with Raney Nickel to form 3-substituted pyridines. A one-potsynthesis of 2-aryl-2,3-dihydrothieno[2,3-b]-pyridines from thiosemicarbazide is described as well.