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Furthermore , and also in contrast to a previous report on closely related compounds , the spiroacetal derivatives do show interactions with tubulin , even though the precise mechanism and the binding site still remain to be established .
 Chemical: spiroacetal
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: spiroacetal