Marina Towers, a 12-year-old, 282 unit high-rise apartment building on the Alexandria waterfront, is scheduled to be sold for $6.5 million to a group headed by a Virginia architect and a New York City investor.

The upper-moderate-rental range building, which is 100 percent occupied, sits on a long-term leased site at 501 Slaters Lane, just north of the Old Town area. Ownership of the lease also covers the property on it.

Jeff Grene, of the Coldwell Banker real estate firm that acted as co-broker in the transaction with Derant Realty of Arlington, said that the seller is Slaters Lane Corp., a subsidiary of Manhattan Savings Bank of New York, which holds a mortgage on the building that was developed by the Rozansky & Kay company of Washington and then sold in the early 1970s.

The purchasing group is headed by Annandale architect Donald H. Misner and New York City investor Anthony Comparato, according to Grene.

No comment on the transaction, scheduled to be completed July 31, was available yesterday from Misner. But Grene said that there is no plan now to convert the building to condominium ownership. However, that procedure has followed a number of recent sales of major rental properties in this area.