14634
A new copper - catalyzed method for the synthesis of 2 - substituted 6 - guanidino - 9 - isopropylpurines under mild reaction conditions has been developed .
 Chemical: copper; Chemical: 2 - substituted 6 - guanidino - 9 - isopropylpurines
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: copper; Chemical: 2 - substituted 6 - guanidino - 9 - isopropylpurines