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Compound 22 also retained excellent PDE2 selectivity ( 241 - fold to 419 - fold ) over the remaining recombinant , full length PDEs , 1A , 4D , 5 , and 6 .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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