Divergent strategy for the chemoselective synthesis of N-Arylbenzimidazoles and N-Arylindazoles from arylamino oximes
An efficient and divergent synthesis of N-arylbenzimidazoles and N-arylindazoles from arylamino oximes based on reaction conditions selection was developed. The synthesis was approached by treating oximes with BTC and the chemoselectivity was regulated by the amount of Et3N. This switchable N–N and N–C bond formation process features mild reaction conditions, simple execution, high chemoselectivity and broad substrate scope.
Li, Zhen-Hua,Sun, Xiao-Meng,Qin, Jin-Jing,Tan, Zhi-Yong,Wang, Wen-Biao,Ma, Yao
(2020/01/28)
Synthesis, structure and N-N bonding character of 1,1-disubstituted indazolium hexafluorophosphate
1,1-Disubstituted indazolium hexafluorophosphates were synthesized via intramolecular electrophilic amination reactions under mild conditions. The crystal structures were determined and are consistent with the presence of a stable N-N bond, which can be cleaved by hydrogenation. Both experimental and computational studies suggest a covalent bonding character of the N-N bond, with diminished aromaticity of the newly formed pyrazolium ring due to the quaternary ammonium atom (N1), in contrast to the aromatic character of the parent indazole.