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: These data show that the catechol and hydroquinone metabolites of remoxipride have direct toxic effects in HL60 and HBMP cells , leading to apoptosis , while the phenol metabolites were inactive .
### Output Text:
These data show that the <span class="chemical">catechol</span> and <span class="chemical">hydroquinone</span> metabolites of <span class="chemical">remoxipride</span> have direct toxic effects in HL60 and HBMP cells , leading to apoptosis , while the <span class="chemical">phenol</span> metabolites were inactive . 