Here is a quick way to generate a start up msbuild file from your solutions file.
Launch Visual Studio Command prompt and change directory to your project directory and then type the following 2 commands.
msbuild <<your project>>.sln
This file will be generated next to the solution file, it wil be named .sln.metaproj.
All thanks to original post at http://www.codeproject.com/Tips/177770/Creating-MSBuild-projects-from-sln-files