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: A strong association has been found between nephritis and dermatitis due to Tiopronin ( a D - Penicillamine like compound ) and class I antigens B35 - Cw4 , and between dermatitis due to gold thiosulphate and B35 .
### Output Text:
A strong association has been found between nephritis and dermatitis due to <span class="chemical">Tiopronin</span> ( a <span class="chemical">D - Penicillamine</span> like compound ) and class I antigens B35 - Cw4 , and between dermatitis due to <span class="chemical">gold</span> <span class="chemical">thiosulphate</span> and B35 . 