VNP40101M in Treating Young Patients With Recurrent, Progressive, or Refractory Primary Brain Tumors

DISEASE CHARACTERISTICS: * Histologically confirmed\* primary brain tumor, including benign brain tumors (e.g., low-grade glioma) * Recurrent or progressive disease OR refractory to standard therapy NOTE: \*Patients with intrinsic brain stem or diffuse optic pathway tumors do not require histological confirmation, but must have clinical and/or radiographic evidence of disease progression * No bone marrow disease PATIENT CHARACTERISTICS: Age * 21 and under Performance status * Karnofsky 50-100% (for patients \> 16 years of age) OR * Lansky 50-100% (for patients ≤ 16 years of age) Life expectancy * Not specified Hematopoietic * Absolute neutrophil count ≥ 1,000/mm\^3\* * Platelet count ≥ 100,000/mm\^3\* * Hemoglobin ≥ 8 g/dL\* NOTE: \*Unsupported Hepatic * Bilirubin ≤ 1.5 times upper limit of normal (ULN) * ALT and AST ≤ 2.5 times ULN * No overt hepatic disease Renal * BUN \< 25 mg/dL * Creatinine ≤ 1.5 times ULN for age OR * Glomerular filtration rate \> 70 mL/min * No overt renal disease Cardiovascular * Shortening fraction ≥ 30% by echocardiogram OR * Ejection fraction ≥ 50% by gated radionucleotide study * No clinically significant cardiac arrhythmia by EKG * No overt cardiac disease Pulmonary * DLCO ≥ 60% of predicted * Chest X-ray normal (defined as absence of pulmonary infiltrates, pneumonitis, pleural effusion, pulmonary hemorrhage, or fibrosis) AND a resting pulse oximetry reading of \> 94% in room air (for patients who cannot perform the DLCO) * N…