Timothy O'Callaghan, vice president of The Binswanger Cos. has arranged the sale of a 6,262 s/f facility on 16,204 s/f of land at 79 Dresser St./404 West Second St. The sale price was $1.2 million. The buyer, PR Realty, LLC also of South Boston is a private investor and developer. PR Realty intends to redevelop the site for residential use. The seller is a generic pharmaceutical company, marketing products from a wide range of therapeutic areas.