<unk>  is an organic chemical compound having the chemical formula O(CH2CH2)2NH. This heterocycle, pictured at right, features both amine and ether functional groups. Because of the amine,<unk>  is a base; its conjugate acid is called<unk> um. For example, when<unk>  is neutralized by hydrochloric acid, one obtains the salt<unk> um chloride.
Morpholine
Morphine 
Codeine
Normorphine
Methamphetamine
Benzidine
Benzocaine 
Methadone 