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 antiarrhythmic activity of the compound N - ( trans - 3 - hydroxy - 1 , 2 , 3 , 4 - tetrahydro - 2 - naphthyl ) - N - ( 3 - oxo - 3 - phenyl - 2 - methylpropyl ) - piperazine hydrochloride , referred to as P11 , is studied on anaesthesized cats and Wistar albino rats , as well as on non - anaesthesized rabbits .
### Output Text:
The antiarrhythmic activity of the compound <span class="chemical">N - ( trans - 3 - hydroxy - 1 , 2 , 3 , 4 - tetrahydro - 2 - naphthyl ) - N - ( 3 - oxo - 3 - phenyl - 2 - methylpropyl ) - piperazine hydrochloride</span> , referred to as <span class="chemical">P11</span> , is studied on anaesthesized cats and Wistar albino rats , as well as on non - anaesthesized rabbits . 