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: During the night clomipramine ingestion altered the complete sleep architecture in that it suppressed REM sleep and the sleep cycles and induced increased wakefulness .
### Output Text:
During the night <span class="chemical">clomipramine</span> ingestion altered the complete sleep architecture in that it suppressed REM sleep and the sleep cycles and induced increased wakefulness . 