Boston-based Synergy Investments and GreenOak Real Estate have acquired 10 Milk St., an 11-story, 230,209-square-foot office and retail building in Boston.

The partners acquired 10 Milk St. from Oasis Ten Milk Street LLC in a complex transaction by taking on the defaulted $58 million loan held by a securitized lender. The price was the equivalent of about $252 per square foot. This is the eighth property that the two firms have invested in together since 2012.

Built in 1903, 10 Milk St. is located at Washington and Milk streets between State Street and Downtown Crossing. It is currently 70 percent leased to a mixture of first-floor retail, traditional office tenants, and "new economy" businesses including Johnston & Murphy, Lawyer’s Weekly and investment management software company Code Red.

"We have been focused on this property for more than four years and spent the better part of a year negotiating the complicated assumption of a securitized loan," David Greaney, president of Synergy Investments, said in a statement. "It fits our strategy and vision in Boston, and our team worked hard to make this happen."