Respuesta :

Phenobarbital is derivative of Barbituric Acid and Barbituric Acid is derivative of Urea. (structures shown in Fig below)

Urea has H
₂N- group attached to Carbonyl Group (C=O), and such class of comounds conataining H₂N-C=O bond are called as Amides.

Result:
          So, Phenobarbital belongs to Amides.
Ver imagen transitionstate