Naming Alkanes with Substituents - Video Tutorials & Practice Problems

Rules for Naming Alkanes with Substituents Concept 1

So when it comes to naming organic compounds, the name consists of a parent chain, the name of substituents and their locations and a substituent. Now substituent, we're gonna say is an AL Q group that branches off the parent chain. For this portion of naming, we're gonna say the name format is the location of our substituent and then ending with the parent name, right? So as we do more and more of these, the naming format is gonna become second nature to everyone. So just pay attention and take care because there are steps involved. A process remembering the process is the easiest way to name any organic compound you come face to face with.

Naming Alkanes with Substituents Example 1

Here, it says give the systematic name of the following Alcaine. All right. So to name this, we're gonna have to follow the given steps. So step one, we find the longest carbon chain, which is the parent chain and assign name according to the prefixes. Now, if a tie between longest chain, choose the chain with more substituents. Now, when it comes to finding long car longest carbon chain, you have to let go of the fact that we're reading from left to right. When it comes to looking at an organic molecule, you may look left to right, may give you the longest chain or right to left or top to bottom or bottom to top. You have to be able to look in all directions. So if we take a look here, what's the longest possible chain? Let's see, 1234 K, 1234567, 1234567. So it looks like there's two ways they give me seven and regardless of which way you go, if we went this way, we'd have two substituents, this one branching off and this one branching off. If we went the other way, it'd be the same thing where going this way, we'd have these two as substituents. All right. So our longest carbon chain is seven carbons long. Now, step two, assign names to all substituents. And this is important. Step three, start numbering the chain from the closest substituent. If a tie between substituents, compare the next closest substituent if still a tie number in alphabetical order. All right. So if we go down here, I've highlighted what we were just talking about. The longest carbon chain I decided highlighted this way. This gives me a seven carbon chain as the parent chain. And what's highlighted in orange are our substituents. So here we go, 123, we get to this substituent, we go 123. We get to this substituent. It's tied counting the carbon three from either side gets us to a substituent. But if we identify these, this is one carbon. So this would be a methyl group. This is two carbons. So this is an ethyl group. We said if still a tie distance from the ends to the first substituent number in alphabetical order E comes before M which means we're gonna number it this way, 123 and then 4567. Now step four, you're going to assign numbers which gives us the location for each substituent when more than one identical substituents use the numerical prefixes of die for two, try for three and tetra for four. All right. So we have on carbon number three, Ethel. So this, we're gonna say, uh we're gonna use three Ethel. OK. Name substituents in alphabetical order, prefixes do not count, use commas to separate numbers from numbers. And we're gonna use dashes to separate letters from numbers. Letters are not separated from letters. So a lot is being said here. So let's work this out. We're gonna name the substituents alphabetically and we're gonna give their number locations. So Ethel is on carbon number three. So that's three. And remember we're gonna use dashes to separate letters from numbers. So three dash fo methyl's on carbon number 5-5 methyl. And then we have a seven carbon chain, seven carbons is hat and it's an alkene. So it's Hep. So this would be the name of this alkyl group or this, this alkane molecule three ethyl, five methyl heptane. This would be our final answer. Again. It gets a little bit drawing in terms of naming these types of molecules. But with enough practice, it becomes second nature. So keep at it and you'll get to master naming all these different types of organic compounds.

Provide a systematic name for the molecule. 



• A. 7-isopropyl-2,3-dimethyldecane
• B. 2,7,8-trimethyl-3-propylnonane
• C. 4-isopropyl-8,9-dimethyldecane
• D. 2,3,8-trimethyl-7-propylnonane

Draw a structure for 2,6-dimethyl-4-propylnonane. 

• A.
• B.
• C.
• D.

Draw a structure for 4-tert-butyl-3-isopropyl-2-methyloctane.

• A.
• B.
• C.
• D.