I need help crafting a deal

[Edna White]

Good day!  I need suggestions on crafting a sub 2 deal.  

How can I negotiate to buy a house that didn't sell at $749k on the open market, subject to the existing mortgage with cash over, seller pay the broker fee and i buy "as is, where is"?

it was listed last year, I viewed only from outside as the seller had hostile tenants.  Exterior accents are new windows, roof, and determined from sellers age and latest repairs it needs $150,000 of work.  Seller is being in mortgage and houses in that area at $450k estimate.  It is a multifamily.