The owners of the Bank of America Tower at One Bryant Park are expected to refinance the building Monday. The $1.275 billion loan is one of the biggest private financings since 2007. The money, which took building owners Durst Organization and Bank of America nine months to get, will be used to pay back a $950 million loan on the building, to repay investors and to finish work on the tower. Bank of America, Bank of New York Mellon, Wells Fargo Bank, Westdeutsche ImmobilienBank and Helaba Bank are providing the financing. Douglas Durst, the Durst Organization’s chairman, said securing the financing for the tower was part of what allowed him to resign as the company’s co-president. He will stay on as chairman.