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: Compound 1 is a potent A ( 2A ) / A ( 1 ) receptor antagonist in vitro ( A ( 2A ) K ( i ) = 4 . 1 nM ; A ( 1 ) K ( i ) = 17 . 0 nM ) that has excellent activity , after oral administration , across a number of animal models of Parkinson ' s disease including mouse and rat models of haloperidol - induced catalepsy , mouse model of reserpine - induced akinesia , rat 6 - hydroxydopamine ( 6 - OHDA ) lesion model of drug - induced rotation , and MPTP - treated non - human primate model .
### Output Text:
Compound 1 is a potent A ( 2A ) / A ( 1 ) receptor antagonist in vitro ( A ( 2A ) K ( i ) = 4 . 1 nM ; A ( 1 ) K ( i ) = 17 . 0 nM ) that has excellent activity , after oral administration , across a number of animal models of Parkinson ' s disease including mouse and rat models of <span class="chemical">haloperidol</span> - induced catalepsy , mouse model of <span class="chemical">reserpine</span> - induced akinesia , rat <span class="chemical">6 - hydroxydopamine</span> ( <span class="chemical">6 - OHDA</span> ) lesion model of drug - induced rotation , and <span class="chemical">MPTP</span> - treated non - human primate model . 