19924
Compounds 4d , 4p , 4l , and 4f exhibited remarkable activity compared with prazosin hydrochloride , which was used as a reference standard in the present study .
 Chemical: prazosin hydrochloride
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: prazosin hydrochloride