RATIONALE: Drugs used in chemotherapy, such as gossypol and temozolomide, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. Gossypol may help temozolomide work better by making tumor cells more sensitive to the drug. Gossypol may also make tumor cells more sensitive to radiation therapy. Giving gossypol and temozolomide together with radiation therapy may kill more tumor cells.