14633
A series of 2 , 9 - substituted 6 - guanidinopurines , structurally related to the cyclin - dependent kinase ( CDK ) inhibitors olomoucine and roscovitine , has been synthesized and characterized .
 Chemical: 2 , 9 - substituted 6 - guanidinopurines; Chemical: olomoucine; Chemical: roscovitine
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: 2 , 9 - substituted 6 - guanidinopurines; Chemical: olomoucine; Chemical: roscovitine