If it's a multi-column PDF you might be able to make use of ==>>
k2pdfopt: optimizes PDFs for viewing on e-readers
Or, if you can wrangle the PDF into Word (maybe via this ==>>
Edit PDF content in Word), then you could use Toxaris' add in ==>>
e-Book Tools - a Word add-in to create an ePUB that you can finalise in an ebook editor such as Sigil or Caiibre.
Otherwise - what Turtle91 said.
BR