[Ricardorf]

I can't post the image.. But I was wondering if you could help me find the mecanism for this reaction:

4,5,6,7,- tetrabromo-1H-benzo[d][1,2,3]triazole --> 5,6,7,8- tetrabromo-1,4-dihydrobenzo[d][1,2,3]triazine


I am a student in a Masters degree in Pharmaceutical Chemistry from the faculty of pharmacy of the university of Porto, Portugal, and I need this for a class project.
Thank you anyway!