Provide a systematic name for the following aldehyde. Now, in order to do this, we're going to utilize the following steps:
- Step 1. Find the longest carbon chain, which will represent the parent chain and assign a name according to the prefixes and modifier. The parent chain should include the aldehyde group and a greater number of carbons. If there is a tie between longest chains, choose the chain with more substituents. In this example, we need to include our carbonyl carbon as part of the longest carbon chain. Remember, in terms of numbering, we start numbering from that carbon. Our longest carbon chain would be here. If we look, this is not part of the longest carbon chain because this is our branch group, our alkyl group. It's made up of 2 carbons, so this would be ethyl. We've assigned names to all the substituents.
- Step 3. Start numbering the chain at the carbon of the aldehyde group. This would be: 1, 2, 3, 4, 5, and 6.
- Steps 4 to 6, repeat steps from previous naming topics. If you haven't watched my video on alkane with substituents, I suggest that you go back and take a look. There we talk about steps 4 to 6, where we're basically paying attention to these substituents. We have to give the numerical locations of our substituents, and make sure we name them alphabetically. It also explains how we set up the name, where we use commas to separate numbers and dashes to separate numbers from letters. So here we have an ethyl on carbon 2, so it would be 2-ethyl. Because the aldehyde carbon always gonna be carbon number 1, we don't need to designate where it's located.
So we have a 6 carbon chain, which in alkane form is hexane, but remember, we're changing the 'e' to 'al.' Therefore, the name of this particular aldehyde would be 2-ethylhexanal.