4814
We report here the optimization of human 17 beta - HSD2 inhibitors in the 2 , 5 - thiophene amide class by varying the size of the linker ( n equals 0 and 2 ) between the amide moiety and the phenyl group .
 Chemical: 2 , 5 - thiophene amide; Chemical: amide; Chemical: phenyl
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 , 5 - thiophene amide; Chemical: amide; Chemical: phenyl