9970
Oxidation of other related chromene gamma - secretase inhibitors 2 - 8 resulted in similar difluoroquinone analogs 2a - 8a , respectively .
 difluoroquinone
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 difluoroquinone