The 156-year-old private college -- which counts civil rights activist Coretta Scott King, writer Rod Serling, actor Cliff Robertson and evolutionary scientist Stephen Jay Gould among its long list of notable graduates -- was put up for sale after its parent organization, Antioch University, was unable to finalize an agreement with a group of alumni and former trustees that was interested in taking it over, the Dayton Daily News reported.

The negotiations with the alumni group ended Friday when university officials turned down its "best and final" offer to pay half of the $12.2 million over five years.

Antioch University spokeswoman Lynda Sirk said any potential buyer -- including the alumni group -- must provide full payment up front.

Without a sale, Antioch College plans to close June 30 and reopen in 2012 after reorganizing, university administrators have said.

The college, whose first president was Horace Mann, has about 200 students, down from about 2,000 in the 1970s. Antioch historically offered no class grades, encouraged students to develop their own study plans and incorporated off-campus learning experiences.

Antioch University has campuses in Yellow Springs, as well as Seattle, Los Angeles, Santa Barbara, Calif., and Keene, N.H.