As a native speaker I have never heard the verb "titeln" in actual use. It may exist but I am not so sure about it.
If this lemma is kept it should probably be mentioned that "betiteln" is a synonym which is much more common. (Or better, change this lemma to betiteln altogether ..)
Also the past participle "getitelt" is quite questionable and should probably be changed to "betitelt", which -again- is quite common.
best regards