Photochemical synthesis of triazolo[3,4-b]-1,3(4H)-benzothiazines: a detailed mechanistic study on photocyclization/photodesulfurisation of triazole-3-thiones
作者:A Senthilvelan、D Thirumalai、V.T Ramakrishnan
DOI:10.1016/j.tet.2003.11.053
日期:2004.1
Irradiation of 4-(2-halobenzyl)-5-substituted-1,2,4-triazole-3-thiones under base mediated (CH3CN/2 M NaOH) condition afforded triazolo[3,4-b]-1,3(4H)-benzothiazines and desulfurized triazoles. Benzophenone sensitized photolysis of triazole-3-thiones gave desulfurized triazoles exclusively. The mechanism of the photocyclization/photodesulfurization and the involvement of singlet and triplet energy
在碱介导的(CH 3 CN / 2 M NaOH)条件下辐照4-(2-卤苄基)-5-取代的1,2,4-三唑-3-硫酮,得到三唑并[3,4- b ] -1, 3(4 H)-苯并噻嗪和脱硫三唑。三唑-3-硫酮的苯甲酮敏化光解仅产生脱硫的三唑。讨论了光环化/光脱硫的机理以及单线态和三线态能级的参与。