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: A series of aryl - piperazine analogues of buspirone and other 5 - hydroxytryptaminergic agonists were tested for their ability to reverse haloperidol induced catalepsy .
### Output Text:
A series of <span class="chemical">aryl - piperazine</span> analogues of <span class="chemical">buspirone</span> and other <span class="chemical">5 - hydroxytryptaminergic agonists</span> were tested for their ability to reverse <span class="chemical">haloperidol</span> induced catalepsy . 