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 effects were similar to those induced by diazepam , whereas the partial agonist Ro 16 - 6028 ( tert - butyl - ( S ) - 8 - bromo - 11 , 12 , 13 , 13a - tetrahydro - 9 - oxo - 9H - imidazo [ 1 , 5 - a ] - pyrrolo - [ 2 , 1 - c ] [ 1 , 4 ] benzodiazepine - 1 - carboxylate ) showed very weak efficacy in these biochemical tests .
### Output Text:
These effects were similar to those induced by <span class="chemical">diazepam</span> , whereas the partial agonist <span class="chemical">Ro 16 - 6028</span> ( <span class="chemical">tert - butyl - ( S ) - 8 - bromo - 11 , 12 , 13 , 13a - tetrahydro - 9 - oxo - 9H - imidazo [ 1 , 5 - a ] - pyrrolo - [ 2 , 1 - c ] [ 1 , 4 ] benzodiazepine - 1 - carboxylate</span> ) showed very weak efficacy in these biochemical tests . 