5.3 Naming the Parent Chain

5.3 Naming the Parent Chain

• It is possible to see double and triple bonds in the same compound, which is rare.

• There are three double bonds and two triple bonds in this compound.
• It is a triendiyne.
• Double bonds are listed first.

• Find the unsaturation in the following compound and figure out how it will be represented in the name of the compound.

• The compound has two bonds, one double and one triple.
• The unsaturation for this compound is -enyn-, because double bonds get listed first.

• Find the unsaturation and identify how it will be represented in the name of the compound.

• The root of our name is going to be the chain of carbon atoms that make up the parent compound.
• Everything else in the compound is connected to a specific location.
• We need to know how to choose the parent carbon chain.

• A chain of five carbon atoms is called a pentane.
• A ring of six carbon atoms is called cyclohex and a ring of five carbon atoms is called cyclopent.

• The tricky part is figuring out which carbon chain to use.

• There is a hierarchy for this as well.

• The first thing we need to do is find the functional group and make sure it is connected to the parent chain.
• If there are two functional groups, one of them gets priority.
• The one that needs to be connected to our parent chain is the functional group that gets priority.
• The last possibility is eliminated because the functional group is not connected to the parent chain.

• If there are more possible parent chains, we look for one that also includes the double bond.

• We need to choose a parent that includes both carbon atoms of the double bond.
• Only one parent chain has the functional group and carbon atoms.
• The OH is connected to a carbon that is part of the chain.
• The oxygen atom is not counted as part of the chain.
• The chain has it attached to it.
• There are four carbon atoms in the chain above.

• If there is no functional group, we look for the longest chain that includes the double bond.
• If there is no double bond, we look for a triple bond, and choose the longest chain that has the triple bond in it.

• We are moving our way backwards through the naming process.
• If we can pick out the highest ranking functional group in the compound, we can name the parent correctly.
• The first thing we do is ask which functional group has priority.

• A functional group is the first thing we look for.
• The carbon atom of the carboxylic acid group must be included in the parent chain of this compound.
• We are looking for a double bond.
• That should be included in the parent chain.
• This answers our question.
• The double bond and functional group are more important than the triple bond in the parent chain.

• The number of carbon atoms in this chain is counted.
• The carbon atom of the carboxylic acid group is included.