How to locate msbuild

I am trying to build a SLN with:

- powershell -File myscript.ps1
. "C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\Common7\Tools\VsDevCmd.bat"
msbuild /p:Configuration=Debug my.sln

For some reason it does not find msbuild. Now looking at the Environment after VsDevCmd, there is also nothing added to find that.

Can anyone provide a working example of how to call msbuild in Travis?