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 effects of NIK - 247 on cholinesterase , scopolamine - induced amnesia and spontaneous movement were examined and compared with those of the well - known cholinesterase inhibitors tacrine and E - 2020 .
### Output Text:
The effects of <span class="chemical">NIK - 247</span> on cholinesterase , <span class="chemical">scopolamine</span> - induced amnesia and spontaneous movement were examined and compared with those of the well - known cholinesterase inhibitors <span class="chemical">tacrine</span> and <span class="chemical">E - 2020</span> . 