In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Lethal anuria complicating high dose ifosfamide chemotherapy in a breast cancer patient with an impaired renal function .
### Output Text:
Lethal anuria complicating high dose <span class="chemical">ifosfamide</span> chemotherapy in a breast cancer patient with an impaired renal function . 