Boston Realty Advisors (BRA) has sold a six-unit brownstone building in Boston’s Back Bay for $3,550,000, or $591,667/unit.

The building at 5 Marlborough St. was last sold in 2003 for $2.46 million, according to records obtained from The Warren Group, publisher of Banker & Tradesman.

The team of Christopher Sower, Kristy Ganong and Jason Weissman, all of Boston Realty Advisors, represented the seller, while Michele DeAngelis, vice president of Coldwell Banker, represented the buyer.

"5 Marlborough Street was an extremely unique offering. It’s location on the first block of Marlborough, made it a very rare opportunity," said Sower, managing director and partner of Boston Realty Advisors.

"We were pleased to participate with Ms. DeAngelis. Boston Realty Advisors is committed to cooperating with the brokerage community at large on our investment sales offerings. We have always believed that this adds value to the owners of the properties that we represent," said Weissman, principal and founder of Boston Realty Advisors.