18216
Structurally , compounds 1 and 3 are tremulane - type sesquiterpenoids with an unusual perhydroazulene carbon skeleton .
 Chemical: tremulane; Chemical: sesquiterpenoids; Chemical: perhydroazulene; Chemical: carbon
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: tremulane; Chemical: sesquiterpenoids; Chemical: perhydroazulene; Chemical: carbon