11314
Ring closing tactics to convert this hit series into a novel 2 , 3 , 4 , 5 - tetrahydro - 1H - pyrido [ 4 , 3 - b ] indole based CRTh2 receptor antagonist series is presented .
 Chemical: 2 , 3 , 4 , 5 - tetrahydro - 1H - pyrido [ 4 , 3 - b ] indole
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: 2 , 3 , 4 , 5 - tetrahydro - 1H - pyrido [ 4 , 3 - b ] indole