Taxi, The Jack Demsey's that you refer to was the second location.
Jack Demsey's original location was on 8th Avenue.
It closed and then it moved to Broadway.
From the NY Times:
"Jack Dempsey's Broadway Restaurant, known popularly as Jack Dempsey's, was a restaurant located on Broadway between 49th and 50th streets in Manhattan, New York.
Owned by world Heavyweight boxing champion, Jack Dempsey, it was considered by many as an American institution. The restaurant originally opened for business as Jack Dempsey's Restaurant on Eighth Avenue and 50th Street."