Boston-based private equity firm Rockpoint Group has acquired 75-101 Federal St. in the Financial District for $326.5 million from Pearlmark Real Estate Partners of Chicago.

The 800,000-square-foot property contains two connected office towers overlooking the Winthrop Square garage, where the city recently sought proposals from developers for a major mixed-use development. Eight developers submitted proposals in April to replace the garage with towers up to 780 feet tall.

Accordia Partners LLC of Boston, one of the developers that submitted proposals, has suggested that 75-101 Federal St. can be incorporated into its 800,000-square-foot proposal for the garage property redevelopment. Accordia’s plan calls for 10,000 square feet of public gallery space abutting and connecting to 75-101 Federal St. as part of a $530-million, 56-story tower containing 275 hotel rooms, 140 condominiums, retail, civic and meeting space.