 During his Ph.D. he synthesized in 1887 2,8-Dimethyl-6H,12H-5,11-methanodibenzo-[b,f][1,5]diazocine from p-toluidine and formaldehyde.This substance is now known as the Tröger's base.Because he was not able to give a structure of the new compound Johannes Wislicenus, the new director of the department, assigned a mediocre grade for Trögers thesis.