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: METHODS : We present the first case report of a woman with hyperthyroidism treated with propylthiouracil in whom a syndrome of pericarditis , fever , and glomerulonephritis developed .
### Output Text:
METHODS : We present the first case report of a woman with hyperthyroidism treated with <span class="chemical">propylthiouracil</span> in whom a syndrome of pericarditis , fever , and glomerulonephritis developed . 