Alicycles and Aromatics!

- Carbon chains can form two types of closed loops
- Alicyclics are loops usually made with single bonds
- Cyclo- is added in front of the parent chain. If a parent chain is a loop standard naming rules apply.

Cyclopentane
- Here are two ways to draw a cyclic.

Line Diagram

Condensed Structural Diagram

- Numbering can start anywhere and go Clockwise or Counterclockwise on the loop but side chain numbers must be the lowest possible.

Example:

1,3,5 trimethyl cyclohexane

- Loops can also be a side chain

- Some rules apply but the side chain is given a cyclo- prefix

Example:

2 cyclopropyl 2 pentene

Aromatics

- Benzene (C6H6) is a cyclic hydrocarbon. (Careful analysis shows that all C-C bonds are identical and really represent a 1.5 bond.

Examples of Benzene:

Aromatic Nomenclature

- Abenzene molecule is given a special diagram to show its unique bond structure

- Benzene can be a parent chain or a side chain.

- As a side chain it is given the name "Phenyl"

Examples:

1,2,3,4,5 pentamethyl benzene

1 bromo 4 phenyl butane