1. contain more than one ring bicyclictricyclictetracyclicetc 3.14 Polycyclic Ring Systems

2. spirocyclic fused ring bridged ring Types of Ring Systems

3. one atom common to two rings Spirocyclic

4. adjacent atoms common to two rings two rings share a common side Fused Ring

5. nonadjacent atoms common to two rings Bridged Ring

6. equals minimum number of bond disconnections required to give a noncyclic species Number of Rings

7. requires one bond disconnection requires one bond disconnection Monocyclic

8. requires two bond disconnections Bicyclic

9. Bridged Bicyclic

10. carbon skeleton is tetracyclic Steroids

11. 3.15 Heterocyclic Compounds

12. 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 Heterocyclic Compound

13. Ethylene oxide Tetrahydrofuran Tetrahydropyran Oxygen-containing Heterocycles

14. Pyrrolidine Piperidine Nitrogen-containing Heterocycles

15. Lipoic acid Lenthionine CH 2 CH 2 CH 2 CH 2 COH O Sulfur-containing Heterocycles