24089
In order for a compound to demonstrate potent 5 - HT6 receptor agonist properties , the indole N ( 1 ) should be unsubstituted , an alkyl group such as 2 - methyl is needed and finally halogen substituents in the indole 5 - position ( fluoro , chloro or , bromo ) were essential requirements .
 Chemical: indole; Chemical: alkyl; Chemical: 2 - methyl; Chemical: halogen; Chemical: indole; Chemical: fluoro; Chemical: chloro; Chemical: bromo
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: indole; Chemical: alkyl; Chemical: 2 - methyl; Chemical: halogen; Chemical: indole; Chemical: fluoro; Chemical: chloro; Chemical: bromo