If you aren't a seasoned developer in NYC you are asking for major problems.
In most cases condemnation might very mean that the building is beyond salvaging and you will have to do a complete demolition. Therefore, you are only purchasing land.
You might be better off buying real estate at retail and do cosmetic renovations.
Make sure your proforma analysis examines all options.
Finding a property in need fo some TLC can be difficult--many management companies have either rebuilt them or the city, as another agent mentioned on here, has gotten rid of a significant number of them. Are you looking for a single family property? Such as a house (multifamily, townhouse, etc) or a rental building? If you have any questions feel free to contact me
400 E 84 St