Write the IUPAC name for each of the following:
b.

Question

Write the IUPAC name for each of the following:

b.

Accepted Answer

Hi, everyone. Welcome back. Our next question says, what is the Iupac name of the given compound? And we have a condensed structural formula that shows CH three C with a double bond to an och and that C has a bond to C two C three and then CH three. So it looks like on first glance, a four carbon chain with a ketone on the second carbon and an ayl branch on the third carbon. Our answer choices are a 12 dimethyl one Butan B three, methyl, two pone, C three ethyl, two Butan or D three, methyl, four pone. So what are our steps in naming a compound? We start by finding the longest carbon chain and this isn't always straightforward. So when we look at our structure, as I said, it looks at first glance like a four carbon chain with an ethyl branch. But if we look at it more closely instead of just going through the four carbons, just straight across. If we go up into the eyl branch, let's look at how many carbons we have. Now a quick note here because the ketone in this structure is our highest priority group we want our chain to include the ketone. So we wouldn't count these four carbons on the right, that don't include the ketone. So let's go from left to right, starting with the first C on the left. So that's 12, there's the carbon, carbon three. And now instead of going on on this horizontal branch, let's go up into what looks like an Ayl branch, like it's a 45 because there are two carbons in that branch. So if we go up into that, instead of having it be a branch, we have a five carbon chain instead of a four carbon chain. So instead of a four carbon chain with an ethyl branch, we'll have a five carbon chain with a methyl branch. So we have a five carbon chain. So five carbons was our longest chain and it has a ketone. So we will give it the name, it was based on pentane. We'll give it the name Pone since it has a ketone group in it. Now, we just need to locate that carbon group. So we need to number the chain to provide the lowest possible number for the ketone carbon. So number the chain. So the carbon carbon has the lowest possible number. So I'll put these numbers in red here. If I start on the left, I have 12, my carbonel chain is on carbon two. If I numbered from the right. So little blue numbers starting from the right side 123 and the carbon carbon would be number four. So numbering, starting from the left, raise these blue numbers gives my ketone the lowest possible number. So I'll just continue on numbering 345. So now we want to put a locator on that pone. So I have two hyphen pagone since the carbon, carbon is at carbon two, remembering that there we put hyphens between numbers and letters. So now our next step is to locate and name my substituents. So my ketone is obviously part of the main name. I just need to deal with that methyl group. So it's on carbon three. So I have three hyphen methyl. So let's put it all together and I have three methyl, there's just one subsistence. So I don't need to worry about sorting any others. And then hyphen two pinon. So when I look at my answer choices that matches with choice B to see why the other choices are incorrect. Choice A has the main chain identified as Butan know. So that used a four carbon chain instead of a five carbon chain. So choice A is incorrect. Choice C three ethyl, two. Butan again, incorrectly used a four carbon main chain and then choice D three methyl, four pagone number, the carbons, the other direction. So that would be not the lowest possible number for my ketone. So that's why choice D is incorrect. So again, the OPEC name of our given compound is choice B three methyl two pagone. See you in the next video.

Write the IUPAC name for each of the following:
b. <IMAGE>

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Key Concepts

IUPAC Nomenclature

Functional Groups

Structural Representation