In this video, we're going to focus on naming ethers. We're going to talk about the common names and also the IUPAC names. So let's start with this example.
Let's say if we have CH3OCH2CH3. What is the common name of this particular ether? So notice that we have a methyl group on the left. And on the right, we have an ethyl group. If you recall, methane is associated with one carbon, ethane is for two carbons, propane is for three, butane is four, pentane is five, hexane is six, heptane is seven, octane is eight, nonane is nine.
So we have two carbons on the right, so it's an ethyl group, one on the left, methyl. And to put it together, we need to alphabetize it. So it's called ethyl methyl ether.
This is the common name. Now what about the IUPAC name? What is it for this particular example? Let's retry it.
So the longest structure, or the longest chain, is the two carbons on the left. So I'm going to write it like that. And then I'm going to draw this as a substituent. So we have an OCH3 group.
So notice that on carbon 1, we have this group, which is called a methoxy group, as a substituent. So it's 1-methoxyethane, or simply, methoxyethane. The ethane is the parent chain of the two carbons on the left.
So this is the IUPAC name for this particular ether. Let's try another example. Let's name this particular ether. Feel free to pause the video and work on this example. On the right we have two carbons, on the left we have four carbons.
So we have a butyl group on the left and an ethyl group on the right. So it's already in alphabetical order so it's called butylethyl ether. Now that's the common name, but what about the IUPAC name? So let's redraw it. So here's the longest chain, it's four carbons, and the substituent is this portion of the molecule.
OCH3. is known as methoxy as a substituent because it has only a methyl group. Here we have an ethyl group attached to it, so this is called ethoxy. So it's 1-ethoxy, and the parent name is butane.
It's a 4-carbon alkane, so 1-ethoxy-butane. That's the IUPAC name for that example. Now how about this example? How can we name this particular ether?
So notice that we have an ethyl group on both sides. So we have two ethyl groups. It's not called ethyl-ethyl ether, but it's simply diethyl ether.
So that's the common name. Now for the IUPAC name, we're going to treat one side as a substituent. So I'm going to write it as OCH2CH3.
So, once again, this is ethoxy, and it's on carbon 1. But if it was here, this would be carbon 1. So, for a 2-carbon chain, no matter where you put the ethoxy group, it's going to be on carbon 1. So, you could just call it ethoxy ethane. And that's all you've got to do for this one. Here's another one that we could try. What's the common name for this particular ether?
Now, on the right, we have an ethyl group. On the left, we have three carbons, but based on the way it's connected, this is an isopropyl group. So, E comes before I.
So, this is ethyl. Isopropyl ether now what about the IUPAC name What is it for this particular molecule? So I'm going to redraw it.
First, I'm going to draw these three carbons because that's the longest chain. So 2, 3. And on carbon 2, I'm going to draw the ethoxy group. So I'm going to rewrite it like this. So you can clearly see that the ethoxy group is on carbon 2. So it's 2-ethoxy, and for a 3-carbon alkane, it's propane.
So 2-ethoxy-propane. That's the IUPAC name for this ether. Now what about this one? Let's focus only on...
the IUPAC name. What is the IUPAC name for this structure? So first, we need to identify the longest chain.
Should we count it from right to left or left to right? If we count it from left to right, we're going to have two substituents at 3 and 4. We have an ethoxy group at 3 and a methyl at 4. If we count it from right to left, The methyl is going to be on carbon 2 instead of carbon 4. So you want to count in the direction that's going to give you the lower numbers. So we want to count that way.
So now we've got to alphabetize it. Which one comes first, ethoxy or methyl? E comes before M, so we're going to put the ethoxy group first.
So it's 3-ethoxy-2-methyl. And for a 5-carbon chain... It's pentane.
So this is the answer. Now what about this one? Let's say if we have not only an ether, but also an alcohol group. and also a halide. How can we name this particular compound?
So which group has more priority the alcohol or the ether? Alcohols typically have more priority than ethers. So to name it we're going to give the OH the lower number so we're going to count it from right to left.
Now we have a bromo group on 4 and a methoxy group on 3. So Br is going to be written first because it has the lower alphabet. So it's 4-bromo-3-methoxy instead of ethoxy because the ether has a methyl group. And then dash 2, we have a 5-carbon chain, so instead of saying pentane, it's going to be pentanol.
the OH is on carbon 2. So that's it, 4-bromo, 3-methoxy, 2-pentanol. Now what about this example? How can we name this particular ether?
Let's start with the common name. So on the right we have a methyl group, on the left we have a cyclopentyl group because it has a ring with five carbons, and C comes before M, so it's going to be called cyclopentymethylether. Now what about the IUPAC name?
Well first, we need to identify the longest chain, and it's clearly the 5-carbony ring. So that's going to be called cyclopentane, and this is the substituent, which is known as methoxy. So it's simply called methoxy cyclopentane.
Well, that is not cyclopentane. I forgot the why. Here it is. Try this one.
Let's say if we have a 6-carbon ring and an OCH2CH3 group. So let's start with the common name. On the right, we have an ethyl. On the left, we have a cyclohexyl group. So C...
comes before E in the alphabet so it's cyclohexoethylether. Now for the IUPAC name, the 6 carbon ring is the longest chain so that's going to be called cyclohexane. And the substituent is ethoxy.
And it's automatically on carbon 1, so we can just write it as ethoxy cyclohexane. Now what if you have a molecule that looks like this? How would you name it?
So we have two ethers. So I'm going to redraw it. So what is the IUPAC name for this compound? So this is a substituent, that's methoxy. We have another methoxy group.
One of them is on carbon 1, the other is on carbon 2. Now the longest chain is the 2-carbon chain in the middle, which is ethane. And since we have two methoxy groups, we're going to call it dimethoxy. So it's 1, 2, dash dimethoxy. Ethane. Now let's try one last example similar to this one.
How would you name this ether? So this is an ethoxy group, and here we have another ethoxy group. Now we want to count it from left to right, not right to left, so we can get the lower numbers.
So we want to make this 1, 2, 3, 4, 5, 6, 7, 8, 9. The longest chain is 9, which is nonane. We have an ethoxy group at 1 and 6. So it's going to be 1, 6, dash, diethoxy, nonane. And that's it. So now you know how to name ethers.