Heterocyclic Amines, Five-atom Rings
        Of the five-atom rings,
        •      the simplest one is pyrrolidine, which is a ring of four 
               carbon atoms and one nitrogen atom, all with single 
               bonds. 
        •      pyrrole is a five-atom ring with one nitrogen atom and two 
               double bonds.
        •      imidazole is a five-atom ring that contains two nitrogen 
               atoms.
     General, Organic, and Biological Chemistry: Structures of Life, 5/e                                                             © 2016 Pearson Education, Inc.
     Karen C. Timberlake
         Heterocyclic Amines, Six-atom Rings
        Of the six-atom rings,
        • piperidine, responsible for the pungent aroma and 
               taste of black pepper, is a six-atom heterocyclic 
               ring with a nitrogen atom.
        • purine and pyrimidine rings are found in DNA and 
               RNA.
        In purine, the structures of six-atom pyrimidine and 
        five-atom imidazole are combined. 
     General, Organic, and Biological Chemistry: Structures of Life, 5/e                                                             © 2016 Pearson Education, Inc.
     Karen C. Timberlake
         Chemistry Link to Health: Alkaloids: Amines 
         in Plants
         Alkaloids are 
         •     physiologically active compounds produced by plants that contain 
               heterocyclic amines.
         •     used in anesthetics, in antidepressants, and as stimulants, and many 
               are habit forming.
         Nicotine, an alkaloid, is a stimulant that
         increases the level of adrenaline in the 
         blood, increases the heart rate, and                                                                                                  N
         increases blood pressure.  
         Nicotine is addictive because it activates                                                                 N                          CH
                                                                                                                                                         3
         pleasure centers in the brain.                                                                                 Nicotine
     General, Organic, and Biological Chemistry: Structures of Life, 5/e                                                             © 2016 Pearson Education, Inc.
     Karen C. Timberlake
         Chemistry Link to Health: Alkaloids: Amines 
         in Plants
         Caffeine
         •     is an alkaloid found in coffee beans, tea, chocolate, and soft 
               drinks.
         •     is a stimulant of the central nervous system.
         •     increases alertness but may cause insomnia.
     General, Organic, and Biological Chemistry: Structures of Life, 5/e                                                             © 2016 Pearson Education, Inc.
     Karen C. Timberlake
         Chemistry Link to Health: Alkaloids: Amines 
         in Plants
         Morphine and codeine are
         •     alkaloids obtained from the oriental poppy 
               plant.
         •     used as painkillers and in cough syrups.
     General, Organic, and Biological Chemistry: Structures of Life, 5/e                                                             © 2016 Pearson Education, Inc.
     Karen C. Timberlake