Finally, thank you.
Have you tried any other solvents?
I have tried dry diethyl ether and now im waiting two days...well, i dont really know because there is no literature for these reaction conditions...i have one reference that could potentially be helpfull, but i cant get it, can you maybe download it for free? here it is the link: The reaction of benzimidazolium derivatives with superoxide
Nagata, Kazuhiro; Itoh, Takashi; Okada, Mamiko; Ohsawa, Akio
Tetrahedron, Volume: 52, Issue: 19, Pages: 6569-6580, Journal, 1996.