I looked it up: there was actually never such a name in the centre of Munich. There was a Adolf-Hitler-Platz in Pasing, a suburb, which is since 1945 again named Avenariusplatz. In the centre, there was a Adolf-Hitler-Straße between 1936 and 1945, which was named before and after Brienner Straße. In the same period, there were several other streets in suburbs, which got the name, e.g. streets, which are today e.g. named Eversbuschstraße and Verdistraße.

Do you have seen the Platz der Opfer des Nationalsozialismus? Or the NS-Dokumentationszentrum München? Perhaps you should have chosen a different tour?

If you want a guided tour through the KZ in Dachau, there is one, see here. You need about 45-60 min with the public transport from the centre of Munich to go there.

By the way, the Tripartite Pact was signed 1940 in Berlin, not in Munich. Therefore, there is no such building in Munich.