23607
Regioselective mono - deprotection of di - tert - butylsilylene acetal was critical in their synthesis .
 Chemical: di - tert - butylsilylene acetal
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: di - tert - butylsilylene acetal