The indole compound associated with fecal and floral smells belongs to which chemical family?

The indole compound associated with fecal and floral smells belongs to which chemical family?

• A. Aldehydes
• B. Amines
• C. Thiols
• D. Esters

Answer: (B)

Indole is a nitrogen-containing aromatic ring; its nitrogen sits in a pyrrole-like position, which places the compound in the amine family. The infamous odors of feces and flowers come from volatile nitrogen-containing heterocycles like indole and its derivative skatole, not from carbonyls, sulfur-containing thiols, or ester groups. The other options involve different functional groups—aldehydes with carbonyls often have sharp or sweet scents, thiols with sulfur produce strong, often rotten odors, and esters tend to smell fruity. So the correct family for indole’s odor compounds is amines.