contain more than one ring

1
3.14Polycyclic Ring Systems

• contain more than one ring
• bicyclic
• tricyclic
• tetracyclic
• etc

2
Types of Ring Systems

• spirocyclic
• fused ring
• bridged ring

3
Spirocyclic

• one atom common to two rings

4
Fused Ring

• adjacent atoms common to two rings
• two rings share a common side

5
Bridged Ring

• nonadjacent atoms common to two rings

6
Number of Rings

• equals minimum number of bond disconnectionsrequi
  red to give a noncyclic species

7
Monocyclic

• requires one bond disconnection

8
Bicyclic

• requires two bond disconnections

9
Bridged Bicyclic

• requires two bond disconnections

10
Steroids

• carbon skeleton is tetracyclic

11
3.15Heterocyclic Compounds
12
Heterocyclic Compound

• a cyclic compound that contains an atom other
  than carbon in the ring
• (such atoms are called heteroatoms)
• typical heteroatoms are N, O, and S

13
Oxygen-containing Heterocycles
Ethylene oxide
Tetrahydrofuran
Tetrahydropyran
14
Nitrogen-containing Heterocycles
Piperidine
Pyrrolidine
15
Sulfur-containing Heterocycles
Lipoic acid
Lenthionine