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

Question

Write the IUPAC name for each of the following:

c.

Accepted Answer

Hi, everybody. Welcome back. Let's look at our next question. What is the Iupac name for the structure below? And we have a five carbon ring. One of the carbons is part of a carbon group next to it. There's a, the carbon next to it has a bromine group and then two carbons away from that is a methyl group. Our answer choices are a Bromine methyl cyclone B two bromo, four methyl Cyclin 55 bromo, three methyl cyclops or D Bromine methyl ketone. Well, before we even get started here, we can eliminate some two answer choices right away. Choice D Bromine methyl ketone. Not only is it in the format of a common name rather than an IAC name? It doesn't even make any sense. It doesn't tell us there's a five carbon ring here. So choice D is just incorrect. Choice. A also Bromine methyl cyclone, there are no numbers. So we have no locations for our substituent. So choice A is definitely going to be incorrect. So we're down to just B and C. So let's start going through the naming process. So first we find the longest carbon chain in this case, that chain is the ring itself. So we have a 12345 carbon ring. So I'll write five ac ring. So we have that prefix of pine and it's a cyclops. But since we have a carbon group inside, we know it's a ketone, it's a ketone, not an aldehyde. Since that carbonel group is in the format R C double bond to an or prime. In this case, the two R groups are the two parts of the ring going around. So we have a five carbon ring with a key to. So we're going to have our base compound name of Cyclo Pen Toone. We had that one ending reflecting the kone. We don't need a number on this because since the carbon carbon is part of the ring, we automatically consider it carbon one. So I'll put a little red number one by that carbon carbon. So no number needed. It's assumed that's carbon one. So now that my next step is to number the ring, so that our other substituents have the lowest possible numbers. So we already know what carbon one is. Which way will we go from there? Well, if I started going clockwise, as I might sort of instinctively do I go to carbon two? No substituents. Carbon three has the methyl group. So that puts my first substituent at carbon three if I remember going clockwise. So I'll put blue numbers here. I put red numbers to go clockwise. Excuse me if I number, going counter clockwise, if garb one is my carbonel and then I go to carbon two and that has a Brahmin group on it. So numbering counterclockwise gives me the lowest number of that first substituent. So I will erase my clockwise numbers and keep going around counterclockwise 34. There's the methyl group on carbon 45. So I have my rings. Now I need to name and locate all of my substituents. So as we said on carbon two, I have bromine. So I would say two hyphen bromo for that one. Then on carbon four, I have a methyl group. So that would be four hyphen methyl. How do I decide how to list them? It's not numerical order, it's alphabetical order or ABC order for short, ignoring any numerical prefixes like die, try et cetera, but I don't have any of those. So I just look at the B and bromo and the am and methyl, the bromo will be first. So put it all together in its name and I have two hyphen bromo, hyphen four hyphen Methyl using hyphens to separate the numbers and letters I would use commas if I had to separate numbers and then I have a cyclone, I don't need a hype in there since I didn't need a number for that name. So for Methyl, I go straight into Cyclo and to none. When I look at my answer choices that matches choice B choice C is five bromo, three methyl cyclops. So you can see that would have been the name if I numbered it going uh clockwise. But again, that gives me a higher number for my substituents. So it's the wrong number order, which is why choice C is incorrect. So once again, the OPEC name for my given structure is choice B two bromo, four methyl cyclops. See you in the next video.

Write the IUPAC name for each of the following:
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Key Concepts

IUPAC Nomenclature

Functional Groups

Structural Representation