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 effect of aniracetam ( Ro 13 - 5057 , 1 - anisoyl - 2 - pyrrolidinone ) was studied on various forms of experimentally impaired cognitive functions ( learning and memory ) in rodents and produced the following effects : ( 1 ) almost complete prevention of the incapacity to learn a discrete escape response in rats exposed to sublethal hypercapnia immediately before the acquisition session ; ( 2 ) partial ( rats ) or complete ( mice ) prevention of the scopolamine - induced short - term amnesia for a passive avoidance task ; ( 3 ) complete protection against amnesia for a passive avoidance task in rats submitted to electroconvulsive shock immediately after avoidance acquisition ; ( 4 ) prevention of the long - term retention - or retrieval - deficit for a passive avoidance task induced in rats and mice by chloramphenicol or cycloheximide administered immediately after acquisition ; ( 5 ) reversal , when administered as late as 1 h before the retention test , of the deficit in retention or retrieval of a passive avoidance task induced by cycloheximide injected 2 days previously ; ( 6 ) prevention of the deficit in the retrieval of an active avoidance task induced in mice by subconvulsant electroshock or hypercapnia applied immediately before retrieval testing ( 24 h after acquisition ) .
### Output Text:
The effect of <span class="chemical">aniracetam</span> ( <span class="chemical">Ro 13 - 5057</span> , <span class="chemical">1 - anisoyl - 2 - pyrrolidinone</span> ) was studied on various forms of experimentally impaired cognitive functions ( learning and memory ) in rodents and produced the following effects : ( 1 ) almost complete prevention of the incapacity to learn a discrete escape response in rats exposed to sublethal hypercapnia immediately before the acquisition session ; ( 2 ) partial ( rats ) or complete ( mice ) prevention of the <span class="chemical">scopolamine</span> - induced short - term amnesia for a passive avoidance task ; ( 3 ) complete protection against amnesia for a passive avoidance task in rats submitted to electroconvulsive shock immediately after avoidance acquisition ; ( 4 ) prevention of the long - term retention - or retrieval - deficit for a passive avoidance task induced in rats and mice by <span class="chemical">chloramphenicol</span> or <span class="chemical">cycloheximide</span> administered immediately after acquisition ; ( 5 ) reversal , when administered as late as 1 h before the retention test , of the deficit in retention or retrieval of a passive avoidance task induced by <span class="chemical">cycloheximide</span> injected 2 days previously ; ( 6 ) prevention of the deficit in the retrieval of an active avoidance task induced in mice by subconvulsant electroshock or hypercapnia applied immediately before retrieval testing ( 24 h after acquisition ) . 