How to publish a paper that does not seem to be within the scope of any journal?

Interdisciplinary papers have this problem a lot. A – now – very influential paper in my field, I was told by the first author, was in limbo for 4 years before it was published, despite the senior author being world-famous.

Persistence is the key. Try to find someone influential who is knowledgeable and you can convince to help you expanding/adapting/explaining the work better and you could then co-submit with.