Real estate investment trust Boston Properties Inc. has agreed to acquire an office building in Manhattan for $280.5 million.

The company will acquire the property at 510 Madison Ave. Boston Properties will pay the aggregate principal and accrued interest on the property’s existing senior mortgage loan and senior mezzanine loan.

On Aug. 10, the company acquired for cash from a third party the junior mezzanine loan that was secured by a pledge of a subordinate ownership interest in the property for $22.5 million. Upon closing, the company will be the sole owner of the property.

The 350,000-square-foot, Class A office tower was developed by Harry Macklowe of Macklowe Properties and designed by Harry Macklowe, SLCE Architects and Moed de Armas & Shannon Architects.

"We are once again pleased to work with Harry Macklowe to acquire an office building with outstanding design in a premier location. Our previous relationship with Harry, which began with the acquisition of the General Motors Building and other assets in 2008, has fostered a productive relationship that helped us successfully acquire 510 Madison Ave.," said Boston Properties’ Chairman and Chief Executive Officer Mortimer B. Zuckerman. "510 Madison Ave. is the only new office development in the Plaza District and, given its modern design and amenities, it is well positioned to attract the highest-quality tenants."