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: The effects of intracoronary administration of methylergonovine were studied in 21 patients with variant angina and 22 patients with atypical chest pain and in others without angina pectoris ( control group ) .
### Output Text:
The effects of intracoronary administration of <span class="chemical">methylergonovine</span> were studied in 21 patients with variant angina and 22 patients with atypical chest pain and in others without angina pectoris ( control group ) . 