Hydroxycarboxylic acids and aminocarboxylic acids can be made to cyclize, forming lactones and lactams, respectively.
Lactones and Lactams
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now I want to discuss lack tones, lack tams and cycle ization reactions. So, guys, it turns out that Esther's in amad can be made to form rings. Okay. And when you have a cyclic Esther or a cyclic amad, thes molecules have their own names that are very prevalent in organic chemistry and that you should be aware of. Okay, so Ah, cyclic. I didn't spell it. There we go. Okay. Whoa. So a cyclic Esther is called a lack tone. Okay. A cyclic Amit is called a lack tam. Okay. And the way that you get thes is through the cycle ization of either hydroxy carb oxalic acids. So here I have an example here. Okay. So ah hydroxy group on a car. Oxalic acid or amino carb oxalic acids as I have here. Okay. Now these molecules are gonna form ring spontaneously when the rings can be five and six members. Why? Because these are very stable rings. So, for example, here I have, um, delta hydroxy evil lyric acid. Okay, notice that when delta hydroxy va lyric acid cycle eyes is, what happens is that this oh comes in right? Attacks the carbon. Neil, you get a tetra Hydro Intermediate but eventually kick out this. Ohh! Okay, so it would just be basically an s terrifically ation reaction. Okay, notice that the size of your ring is gonna be 12345 six. And that's exactly what you would expect. So we get a six member. Great. Okay. Thes equilibrium. Arrows that I drew are purposeful. I sure that they're pretty much in perfect equilibrium. Because if you could make a five or six member of black tone, that's definitely gonna wanna be, you know, it's gonna form an equilibrium. Okay, In fact, that actually haven't done our bodies and our bodies sugars are forming. Lacked owns all the time. Sugars conform. Six other rings and they form lacked. Owns all the time in your body. Okay, so now it's going to lack Tam's. Okay. Lack tam's same idea. Nitrogen could come in, Do a nuclear filic Aysal substitution. Eventually you kick out the O. H. And you could make a former ring. Now, this one this equilibrium arrow is also purposeful Because notice that I'm making a ring smaller than five members in this case I'm making a four member bring That is much, much less stable. In fact, there's a possibly that this doesn't happen on its own. It all because of the fact that it's just so strained that prefer to exist as a chain. It might take some extra help, some extra re agents to make it into a four remembered ring. Okay, makes them so far. So five and six is good. Anything less than that is bad. Also, anything bigger than that also not very favored. Okay, now we get into naming. So how do we name these guys? Well, it turns out that the functional group of a lack tone or lacked, um can also be specifically named by the size of the ring. But instead of saying it's a six carbon black tone, whatever, what we do is we use the Greek symbols. Yeah, from where the original substitution. It would have been so for an alcohol for to make this lack tone here, Sigma ring. That means that my alcohol would have had to be on the Alfa Beta Gamma delta carbon. Okay. And since my alcohol was originally on the Delta carbon, this would be called a delta black tone. Okay, now, if you're ever confused about what type of black toner black Tim you have. You could always just start counting from scratch. You could just say the carbon next to the carbon. Neil is my Alfa on. Then you could just go from there. Just remember that you only count carbon. So it's Alfa Beta Gamma Delta were done. So this is a delta lack tone. Same thing with black Tam's exactly the same. Except that now, since this was smaller, this is what we would call a beta lack. Tam. Okay, Now, not to bore you, but beta lack tam's air. Really important, guys because beta lack tam's air found in pharmaceuticals all time in antibiotics. Okay, so beta lacked hams are extremely good at disrupting the cell membranes of bacteria. Okay, so that's why they work really well in your body. That's what penicillin is. It's a battle act on. All right, so that is really all you need to know in terms of the General features off black tons and lack tam's. So why don't you guys go ahead and try to psych lies this molecule, See what you get and see if you can generalize what the functional group is I don't you need you to name it because way beyond the scope of this course. You don't need to name the exact molecule. But tell me what type of functional group it is and the Greek letter in front of it. So do that now.
Note: If you're thinking that the β-lactam is missing a hydrogen on the N, you are right!
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All right. So just following the general mechanism of nuclear filic a steel substitution, my nitrogen could attack. I would eventually get a teacher Usual intermediate, which would then kick out the Ohh. Okay, so in terms of the size of the ring, the size of the ring would be five. So there's a chance that this could form spontaneously. So what I would get is Ah, five remembered ring with the nitrogen on one side. Okay? And I just have to add the leftover group. So I know that I would now have a methyl group on that nitrogen and I would have a double bond between the two and the three. That looks like it's right there. We're done. OK? Oh, wait. No, I messed up, right? Because it was two and three. It wasn't. It was between three and four. So it actually be right here. Right? Okay, So you might be wondering what happened to this. H don't worry about it. Got lost in the mechanism. Okay, So now if we had to categorize this functional group in general, what we call it I don't want the name. The name is very complicated. We would call it an Alfa Beta Gamma. This is gonna be a gamma. Lacked him. Not quite as cool as Beta locked him. Sorry. Quote awesome guys. So now I just wanna talk about one more reaction than we don't with this page.
Cyclic Anhydrides and Imides
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So the whole point of the sequence of reactions behind me isn't for you. Toe. Memorize this exact sequence. That's not what I'm interested in. I'm just trying to give you an overview of different cycle is ations that we might have missed to this point. So the first one is really important which says that you can use a die acid. Okay, 10 points for whoever can remember. What's the name of that die acid? Remember? Oh, my science. This would be the four carbon di acids. This would be Susan ic acid. Okay, so it's acidic acid in the presence of heat. Can self psych lies and make a cyclic and hydride? Remember, I was telling you guys that anhydride could be made by the combination of to carve oxalic acids coming together. And that's what happened was a diocese, except it would be a ring. Okay, that's the first part. So it turns out that anhydride if you use a combination of ah, mean with water, Okay, you could make a compound that has both a combination of amad on one side and carl oxalic acid on the other. Okay, now, how does that work exactly? Well, think about it like imagine that you have to equip equivalents of your ammonia. And by the way, this is supposed to be NH three. So Wow, My apologies, guys. This supposed to be N h three n. H two. So let's say you have to coolants of NH three. You act on both sides and you get to an it's OK, you get like a diame it. Then you could use water to replace on Lee one of them. So you get Amit on one side and a car works of gas and on the other Now it's interesting about that. Is that if you have a situation where you haven't Amit in a car oxalic acid on the same chain, you can then use heat to bring those together and make what's called in in mind. Okay. And in my mind is a new functional group that we haven't talked about. Think of it almost like an anhydride, but with a nitrogen in the middle. Okay, so it's like anhydride with nitrogen. Okay, Makes sense. Now, guys, it turns out that this in might is actually kind of important because this in M I is made out of Ah, 60 Nick Acid. Right? So sick cynic Acid. So that means that this is actually called Susana Might. Has anyone heard of Oh, and that's right where I am. Has anyone heard of Susana me before? Does that name sound familiar? Guys, it turns out that a re agent that we've used a lot in organic chemistry so far was the cinema. You guys remember NBS and B s? What did NBS stand for? NBS was and bro mo So cinema. Okay, so it's literally this compound. But instead of having an h there having a BR there, isn't that cool? So now you guys know how to make a Susana Meid by using a die acid. Alright, awesome. Again, I'm not asking you to memorize this whole, um sequence just to be familiar with the parts of it. Okay, Awesome. So let's move on to the next video