25852
Based on the pyrrolopyrimidine chemotype , several new series are described , including the benzimidazole series by linking a benzimidazole to the C5 - position of the 4 - amino - pyrrolopyrimidine core and the ketophenyl series synthesized by incorporating a ketophenyl group to the C5 - position .
 pyrrolopyrimidine, benzimidazole, benzimidazole, 4 - amino - pyrrolopyrimidine, ketophenyl, ketophenyl
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 pyrrolopyrimidine, benzimidazole, benzimidazole, 4 - amino - pyrrolopyrimidine, ketophenyl, ketophenyl