Related Dependencies

Is there a possibility, to download a dependency and all it´s related dependencies from MavenCentral?

Yes, if you just want to have the artifact, with its transitive artifacts, but without the metadata, you can use a Copy task.

Task getDeps (type : Copy) {
  from configurations.compile // copies all compile dependencies
  into myDestinationDir

If you wany something more complex, then you need to look at the Ivypot plugin.