6563
Of importance , the anticancer drug 5 - fluorouracil was an excellent substrate for TbU3 , and several 5 - fluoropyrimidine analogs were investigated for uptake and trypanocidal activity ; 5F - orotic acid , 5F - 2 ' deoxyuridine displayed activity in the low micromolar range .
 5 - fluorouracil, 5 - fluoropyrimidine, 5F - orotic acid, 5F - 2 ' deoxyuridine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 5 - fluorouracil, 5 - fluoropyrimidine, 5F - orotic acid, 5F - 2 ' deoxyuridine