17810
The failure of ortho - metalation using unprotected carboxylic acid group compelled us to use directed ortho - metalation in which a tertiary amide was used as a strong ortho - directing group .
 Chemical: carboxylic acid; Chemical: tertiary amide
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: carboxylic acid; Chemical: tertiary amide