24071
Compound 1c incorporates a 1 , 1 - difluoroethyl group , which affords improved microsomal stability when compared to the corresponding ethyl - substituted compound 1a .
 Chemical: 1 , 1 - difluoroethyl; Chemical: ethyl
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: 1 , 1 - difluoroethyl; Chemical: ethyl