FRANKFURT, Germany — IG Farben, the former German chemical giant that used thousands of slave laborers at Auschwitz, said Monday it plans to file for bankruptcy and is unlikely to pay further compensation to victims of the Nazi war machine.

Once the world's largest chemical firm, IG Farben was broken up and ordered into trusteeship by the World War II Allies in 1952. It continued operating as a trust to pay Nazi-era claims, and its shares are still traded on stock exchanges.

Bankruptcy has become unavoidable because a deal to sell real estate holdings, the company's main remaining asset, fell through, trustee Volker Pollehn told a news conference. As a result, no further compensation is likely to be paid, he said.

IG Farben's wartime factories included a synthetic rubber plant at the Auschwitz death camp complex where 30,000 inmates worked until they died or were deemed unfit for work and sent to the gas chambers. The company partly owned Degesch, which made the Zyklon-B poison used to gas death-camp inmates.

Monday's news conference drew about 30 young protesters, who held placards asking "Where Is The Money To Compensate The Victims" and whistled at the trustees as they left.

Henry Mathews, who heads a group of IG Farben shareholders pressing the trust to pay former slave laborers, urged banks owed money by IG Farben to forego their claims in bankruptcy court.

"We want the banks to renounce these claims so the money can be paid to the victims," Mathews said.

I.G. Farben employed an estimated 350,000 prisoners at its chemical factories during the war. Under a 1957 deal with the Jewish Claims Conference, the IG Farben trust agreed to pay $7 million in compensation, mostly to Jewish former prisoners.

Former IG Farben slave laborers are also eligible to claim compensation from a $5.9 billion German fund that in 2001 began compensating remaining former slave laborers and camp inmates.

Most of them had been deported from Eastern Europe and missed out on compensation because they returned to homes behind the Iron Curtain.

IG Farben's German successor companies — BASF, Bayer and Hoechst — were founder members of the industry-government fund, but IG Farben set up its own $295,000 fund in July 2001.

However, the trustees decided the fund was too small to pay credible compensation and had hoped to fill it up with proceeds of the real estate sales, Pollehn said.

The trustees say that all remaining legal claims against the company by former laborers have been settled and that any further payments would have been on a moral and humanitarian basis.

The Claims Conference's Frankfurt office refused to comment on Monday's announcement.