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: SAR studies led to compound 14 with excellent potency ( K ( i ) = 0 . 4 nM ) , selectivity ( A ( 1 ) / A ( 2A ) > 100 ) , and efficacy ( MED 10 mg / kg p . o . ) in the rat haloperidol - induced catalepsy model for Parkinson ' s disease .
### Output Text:
SAR studies led to compound 14 with excellent potency ( K ( i ) = 0 . 4 nM ) , selectivity ( A ( 1 ) / A ( 2A ) > 100 ) , and efficacy ( MED 10 mg / kg p . o . ) in the rat <span class="chemical">haloperidol</span> - induced catalepsy model for Parkinson ' s disease . 