City Council members, union officials, and parents spent yesterday agitating for a last-minute deal to avert layoffs planned for more than 700 school aides.

Council Speaker Christine Quinn said she would hold a hearing on the layoffs, the largest ever under Mayor Bloomberg, and a late-afternoon rally to oppose the firings attracted a large crowd.

But Schools Chancellor Dennis Walcott said this morning that nothing could be done now to avert the layoffs, set to go into effect on Friday.

“DC-37 layoffs will still happen. I’ve been very consistent about that. It’s unfortunate but it’s the reality of the budget situation we face now,” he told reporters after a breakfast to honor the nonprofit organization PENCIL.

“I’ve tried not to send out mixed signals to DC-37,” Walcott said. “The reality is Friday will be the last day for roughly 700 individuals who are members of DC-37.”

Yesterday, Occupy Wall Street protesters joined the rally to support the school aides. But DC-37 is not among the many city unions participating in this afternoon’s massive Occupy Wall Street rally, according to a list posted on the protest movement’s website.