Although searched by some users, it does not seem to be possible to convert Autodesk Inventor presentations (.ipn) directly to DWG format. What some users do instead is that they place the .ipn file into Inventor's DWG and export that to AutoCAD DWG. Not sure how reliable that is, but it is the only thing we have found about ipn to dwg conversion.
Updated: September 20, 2023