For tax implication you may have to pay the long term capital gains tax as per the envisaged law on the subject. For more details you can contact a local tax consultant or your auditor.
For evicting tenants you may first issue notice stating that the building is very old and need to be demolished and reconstructed hence demand them to vacate, if they dont, see if the purchaser is ready to buy it as is where s condition or may file a eviction suit against the tenants.