Alkyl Groups - Video Tutorials & Practice Problems
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IUPAC naming is awesome because it’s pretty easy to master. But unfortunately there are some non-IUPAC names we need to know for this course. These apply mostly to weird looking substituents. Let's take a look.
1
concept
Understanding Non-IUPAC Substituents
Video duration:
6m
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Video transcript
Alright, guys, Now that we know how to name simple Al Keynes, we're going to start increasing the difficulty level slowly. All right, so the first thing that I want to talk about is substitue INTs. What happens if you have a substitue int that you don't recognize the name for? And that's what this next section is about. Okay, so it turns out that even though we try to use the AIPAC system as much as we can, there are a few common substitue INTs that remember common means that it's an old name. This is the name that comes from predates 1919 predates the convention. Okay. And these air names that have just stuck because they used for so long that even though they don't follow AIPAC convention, you're still supposed to know them. Okay, so, unfortunately, there's eight compound. There's eight branches that you should just know the names for no matter what, even though they're kind of random, but you just need to know them. Okay, so let's talk about the first two, and these are gonna be really easy. The first one is just if I have a three carbon chain where the our group. Our meaning along the actual main chain is attached to just the first carbon of the chain. This would be called pro Paul. Okay, so you already know this Actually. Okay, So actually, this part is the AIPAC part. The ones over This'll one right here is AIPAC. Alright? So don't worry about this one. This one you already know. Okay, there's another one that you're supposed to know. Which is how if I have a four carbon chain, if I got four carbon chain and it's attached right there, then that one would be called beautiful. Case these air Easy. Alright, problem. Beautiful. That has to do with the AIPAC nomenclature. But then there are a few days different ways that we can arrange these substitue int. So imagine that I still have a three carbon chain. But instead of being attached to the primary position, noticed that that would be primary cause it's only attached to if you don't count the are it's only attached to one other carbon on that substitue int. What if you attach it to the secondary position? Okay, well, then this gets its own name because not truly appropriate group, Even though has three carbons. It's attached in a different spot. So this one will be called. I saw Problem. Okay. And why is it called isopropyl? Well, because it's an ice, um er of the pro Paul substitute. But still, that does not follow. Like I said, that's not an AIPAC name. That's just the name that someone a long time gave it because they were like, Oh, there's an ice summer of problem. Alright, So, isopropyl the way that I think about it is it looks kind of like a why. So if you see that, you know, it's an isopropyl group. All right? Now, beautiful is even more confusing because beauty can arrange in, actually four possibilities, and all of them are gonna get their own names, Which sucks. So here we go. Beautiful is usually attached at the primary position. Okay, but what if instead of attaching at the primary position of this four carbon chain, what if I attached at the secondary position? Okay, then what we call it? Well, what we would call this is actually just in italics sec. Beautiful. And guess what the sex stands for. It stands for secondary. Okay, So what? We're saying here is that this is a beautiful group that is attached the secondary position instead of the primary position. Like normal. All right, so then how about if instead of being attached to the secondary position now, it's attached to a tertiary position? Okay. Now, remember, in all these in all of these substitutes, I'm talking about Onley the substitute, not the art group. Okay, so what if it's attention in a tertiary position? Well, then this is going to be called TERT Beautiful. Okay. And those air three really important forms of beauty that you need to know. Beautiful set. Beautiful inter beauty. Okay, now it turns out the beetle has four carbon. So there's even one more possibility. Which would be what if it's still attached at the primary position, like normal, But then it has a Y at the end. Kind of like ice approval. Well, then this is gonna get its own name, and that one's gonna be called. Is so beautiful. Okay, so I so beautiful. Looks like isopropyl, except it has this extra ch two in the middle. All right, so those are our proposals and our bugles, they kind of make sense the way that I'm describing them. Hopefully that will help you memorize them a little bit better. But at the end of the day, this is just simple recognition. You should be able to just know what is what. And you will need to know this for many tests Well into or go to even. Okay, I also want to just say one thing, which is that some textbooks and some professors will use a different letter or use a different notation for pro pool and beautiful instead of just saying problem beautiful. Sometimes they'll say en pro Bowl and end. Beautiful. Okay, Now, honestly, I have no clue what the end stands for. I don't I don't know what it is. All I know is that end means that it's a straight chain. Okay, so sometimes your professor will say beautiful sometimes. Maybe A professor says end beautiful. They're the same exact thing. And beauty just says, Hey, this is not is a beautiful. This is not set. Beautiful. This is a straight chain. Beautiful. Alright, cool. Awesome. So now there's just two more than I want us to know. And those air with double bonds. All right, so What if you have a double bond coming straight off of your main chain? It's your main chain is really long. You have a double bond coming right off of it. This gets its own unique name. That's called vinyl. Okay. And you have heard of vinyl before? Vinyl is a plastic. That plastic is made out of these finals double bonds. Okay, so the fact that old records air called vinyls actually has to do with this molecules. But the molecules named vinyl before the actual record was named the vinyl. Okay, so then let's see what if you have a double bond, but you're not attached directly to the art group. Instead, you have a CH two in between. Okay, so it's like a vinyl, but has an extra ch two. This is gonna be called Let me move out of the way in al Ill. Okay, now I understand these air weird words. These air, not words that are fun to remember. But honestly, there's no way to get around it. You just need to know them. Okay, So what I want to do now is do some more practice with AIPAC nomenclature Now, knowing the names of these common substantial. It's okay. So we try to do is remember, we're still gonna follow all the same rules as before. The only difference is that now, if we get a substitue int that looks like that at the end now, we're gonna No, no, the name for it. Okay, so I want to do a as just a free response problem, like we're gonna do it together. So go ahead and try to solve it. And then when you're done, go ahead and go to the next video.
Quick note:"n" stands for normal:)
Pro Tip:For the butyl groups, you can use the number of substituent carbons attached to it to determine the prefix on the name. (i.e. Butyl with 2 carbons branching off of it is a secondary, or sec-butyl)
2
example
Name the following alkane
Video duration:
2m
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Video transcript
Alright, guys. So for some of you, this was actually a really easy problem for others. Maybe you guys got a little bit confused. Okay? Because what I did do is I tried to Tricky. Okay, this is a tricky question. I gave you this group over here, and that kind of looks like a Turk. Beautiful. Right. So you were looking at that, and maybe you thought this was a tribunal group, But actually, if you follow through with the rules, you would find out that that is not a turf you'll group. So let's go ahead and get started. First, you would find the longest carbon chain. The longest carbon chain was actually just like that. Okay, Now, obviously, you could have also gone from the top or from the bottom. It doesn't matter, because all three of these groups are the same. So it doesn't matter which road we take because all roads lead to the same thing. Okay, so that's her longest carbon chain. And then we would say, Okay, where do you want to start? Numbering from where? With one start with one start here in the blue. Would it start here in the red the answers, it would start in the red. Okay, so then that means that I would have How many substitue INTs I would only have to substitue inside. Have one here, and I would have won their What type of substitutes are these? Do these need common names? Thes air, Just metal groups. Okay, so this is actually a molecule that you could have perfectly named without knowing the comments of stitch. What names? Okay, the trick is that a lot of you guys thought that was a tribunal and made your longest change shorter than it needed to be. Okay, so we're gonna go ahead and trying to get rid of that blue circle. Okay? Okay. So we're gonna go ahead and talk about locations. This would be, too. And once we have that, that's really all we need. We're ready to start listing everything out. So, for root, what is our route? 1234567 So we're really loving these hep Danes, Okay. And then what are our substitute? Wint's are substitutes are going to be a two comma to dimethyl, and that's it. We don't have other types of substitue INTs, so that would actually just be the name. It would be too common to dime Ethel. Hefty. Okay, Words never get spaces or dashes between them, so these would just go right together. Okay, so that was easy. That was just a little bit. I was just testing you guys to see if you remember the rules. Now it's going to the next one, and I will. You know, the next one does need a common name, so go ahead and try to solve it.
Remember to always apply IUPAC rules 1-5 before deciding if a substituent is common or not! Let’s try another.
3
example
Name the following alkane
Video duration:
3m
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Video transcript
All right. So for this one, the longest carbon chain Waas like this. Okay, if you went ahead and started from the top over here, that's fine. Like I said, both of those roads lead to the same place, so it doesn't matter. Same distance. So then how maney substitutes do I have to? Which way should I should I number? I should number my one over here. Right? And go that way. Cool. So then what are the locations of these? That should be 35 Alright. How big is my chain? It looks like it's a non ing for root for that's right route. The route is a non ing. Okay, so now we just have to name those substitue INTs. Okay. And normally this would be easy, except that one of my substitute winces nasty looking. This guy right there. The other one was easy. It was just a ethel group, but the one in the middle sucks. It's, like, really big and bulky. How do I name that? Well, we're gonna have to use our common names. So three is easy. Three is just three Ethel. Okay, but five is actually gonna be We're going to look back up here and say Okay, How maney carbons does it have four? 1234 I'm gonna look in my bugles. Which one does it look like? It actually looks like my sec. Beautiful. Okay, because the SEC beauty is the one that's attached to that secondary position. Let's see this one. If it iss not including the main chain, that carbon is secondary. So this is SEC beauty, so this is gonna be five sec. Beautiful. All right, so now all we have to do is put the name together. So let's go ahead and name this guy. Now, which one do you think I should put first, the five sec Beautiful. Or the three? Ethel. So it turns out, Remember I told you as prefixes do not count. So sec is not gonna count. Turk is not going to count. All right, so the name of this should be, um I'm sorry. Should be five sec beautiful than three. Ethel. Non ing. Isn't that cool? Snow? You guys know how to use that? Now? I do have to teach you guys one exception. Okay, so there's one exception to the rule that prefixes don't count on. I'm gonna write this here prefixes. I'm just gonna say prefix that counts, okay? There's only one prefix that counts, and that is is Oh, okay. I saw Whatever. All right. I'm actually gonna write that. I saw whatever. Whether that's is so beautiful. Isopropyl the ISO in is a beautiful isopropyl, actually does count towards the alphabetical priority. Why is that? I don't have a shot in hell and knowing, all right, I've actually asked a bunch of organic comes to professors at different schools what they thought. And they always give me an explanation about how, like the ISO is not. I tell a size and TERT is I tele sized, but it still doesn't make sense. It's still kind of random. So in the end of the day, it just means that some professor, some research scientists decided that is a was going to count on the other ones. Don't What's important for you guys to know that is accounts. I just want you to memorize that, Okay? The other ones don't count them. So, tri Tetra sec neo, whatever I give you as a as a prefix doesn't count. Except for ISO. Okay, cool. So let's go ahead and move on.
Iso, just like cylo and neo should be considered when alphabetizing. However, prefixes such as tert-, tetra-, sec-, tri-, di- and so forth can be ignored.
Awesome. Now you know how to name pretty much any branched alkane. Party time!