21033
The synthesis of some new tetrahydroquinolines , tetrahydropyrimido [ 4 , 5 - b ] quinolines , and tetrahydropentaazacyclopenta [ a ] anthracenes structurally related to some DNA intercalators is described .
 tetrahydroquinolines, tetrahydropyrimido [ 4 , 5 - b ] quinolines, tetrahydropentaazacyclopenta [ a ] anthracenes
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 tetrahydroquinolines, tetrahydropyrimido [ 4 , 5 - b ] quinolines, tetrahydropentaazacyclopenta [ a ] anthracenes