The whole point of the sequence of reactions behind me isn't for you to memorize this exact sequence. That's not what I'm interested in. I'm just trying to give you an overview of different cyclizations that we might have missed to this point. The first one is really important which says that you can use a diacid. Ten points for whoever can remember what's the name of that diacid. Remember, oh my science. This would be the 4-carbon diacids. This would be succinic acid. Succinic acid in the presence of heat can self cyclize and make a cyclic anhydride. Remember I was telling you guys that anhydrides could be made by the combination of 2 carboxylic acids coming together. That's what would happen with a diacid except it would be a ring. That's the first part.
It turns out that anhydrides, if you use a combination of amine with water, you could make a compound that has both the combination of amide on one side and carboxylic acid on the other. How does that work exactly? Think about it like imagine that you have 2 equivalents of your ammonia. By the way, this is supposed to be NH3. Wow, my apologies guys. This is supposed to be NH3 not NH2. Say you have 2 equivalents of NH3. You act on both sides and you get 2 amides. You get like a diamide. Then you could use water to replace only one of them. You'd get an amide on one side and a carboxylic acid on the other. What's interesting about that is that if you have a situation where you have an amide and a carboxylic acid on the same chain, you can then use heat to bring those together and make what's called an imide. An imide 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. It's like an anhydride with nitrogen. Makes sense?
Now guys, it turns out that this amide is actually kind of important because this amide is made out of succinic acid. That means that this is actually called succinamide. Has anyone heard of that's right where I am. Has anyone heard of succinamide before? Does that name sound familiar? It turns out that a reagent that we've used a lot in organic chemistry so far was succinamide. Do you guys remember NBS? NBS. What did NBS stand for? NBS was n-bromo succinamide. It's literally this compound but instead of having an H there, having a Br there. Isn't that cool? Now you guys know how to make a succinamide by using a diacid. I'm not asking you to memorize this whole sequence, just to be familiar with the parts of it. Awesome. Let's move on to the next video.