21503
Nitroaryl moieties are useful components in the design of hypoxia - selective imaging agents and prodrugs because one - electron reductases can convert the nitroaryl group to nitroso , hydroxylamino , and amino metabolites selectively under low oxygen conditions .
 Nitroaryl, nitroaryl, nitroso, hydroxylamino, amino, oxygen
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Nitroaryl, nitroaryl, nitroso, hydroxylamino, amino, oxygen