Transcript for:
Carboxylic Acid Derivatives - Amides, Esters, and Anhydrides

hello everybody my name is Iman welcome back to my YouTube channel today we're covering chapter 9 for mcow organic chemistry and this chapter is about carboxilic acid derivatives now we saw in the previous three chapters that carbonal are susceptible to attack by everything from water to amines to other carbonal containing compounds the focus of this chapter is going to be to describe the carboxilic acid derivatives that are going to appear on the MCAT and that's going to include amides Esters and anhydrites we briefly covered a little bit of information about how to go from carboxilic acids to amides Esters and anhydrates but today we're going to review that content and cover a couple of new things in addition the objectives that we're going to talk about in this video are the following first we will talk about amides Esters and anhydrides we will describe how to name them them we're going to describe their reactivity comparatively and we'll also remind ourselves of a couple of things from chapter 8 in regards to amides Esters and anhydrides second objective is talking about reactivity we're going to talk about relative reactivity of these derivatives steric effects electronic effects and even strains in some cyclic derivatives and then the last and final objectives for this chapter is nucleophilic AAL substitution reactions we're going to talk about three anhydride cleavage transesterification and hydrolysis of amides so let's go ahead and get started with our first objective amides Esters and anhydrides now these are all carboxilic acids derivatives each of these is formed by a condensation reaction with a carboxylic acid so that's a reaction that combines two molecules into one while losing a small molecule in this case that small mole molecule is you guessed it water which is Created from the hydroxy group of the carboxilic acid and a hydrogen that's associated with the incoming nucleophile now for each of these carboxilic acid derivatives amides Esters and hydrides we're going to focus on the Rel the relevant nucleophile that forms the derivative and then the nomenclature of the function group all right and we're going to go one by one so first we're going to start with amides all right amides are compounds with the general formula r c n R2 they are named by replacing the OIC acid with amide all right so alkal substituents on that nitrogen are also going to be listed at they're going to be listed as prefixes and then their location specific specifically is going to be specified with the letter N all right so here we have some examples all right this is NE ethyl n methyl butanamide all right so notice how this is going to be that main chain that connects to the nitrogen and has the carbonal in it all right that's going to be if it was a carboxilic acid if this was an O right here you would call it but OIC acid remember that amides are named by replacing that OIC acid with amide so that's where we got buttin amide from and then we also still have to address the fact that there are two substituents Associated or bounded to this nitrogen those are an ethyl and a methyl group and like we said their location is specified with the letter N so we write n ethyl that's telling you that this ethyl group is associated with the nitrogen then n methyl 2 again tell you that there is an ethyl that is binded to the nitrogen group all right here's another example so this is that main chain it has two carbons if it was a carboxilic acid you would call it ethanoic acid remember you replace the OIC acid with amide so ethanamide cool then you have to address what is attached to your nitrogen group here we just have two methyls so we can write NN dimethyl Ethan amide all right so that's how we would name amides now amides are generally synthesized by the reaction of other carboxilic acids derivatives with either ammonia or an amine and you're going to note that when we recover some of the reaction mechanism of this that the loss of hydrogen from the nucleophile is required for this reaction to to take place and so only primary and secondary amines are going to undergo this reaction all right before I remind you of the reaction which is written up here I do want to say one more thing that's important I briefly covered it in the last chapter because we are going to cover it in this chapter and here we are covering it cyclic amides they are called lactum all right and they are named according to the carbon atom bonded to the nitrogen so this first molecule right here this is called a beta lactum all right it's called a beta lactum beta lactum contain a bond between the beta carbon and the nitrogen here this is a Gamal actum all right it contains a bond between the gamma carbon and the nitrogen and so on and so forth this would be Delta lactum and Etc all right now amides May or may not participate in hydrogen bonding it depends on the number of alkal groups they have bonded and therefore their boiling points may be lower or on the same level as the boiling points of carboxilic acids all right now as a friendly reminder we learned in the previous chapter that carboxilic acids can be converted into amides if the incoming nucleophile is ammonia or an amine all right and this was the setup for that kind of reaction you could have carboxilic acid react with an amine and you can get an amide and something that was important that we pointed out was that amides exist in a resonance state where delocalization of the electrons occurs here between this nitrogen and carbon and the carbon and oxygen so between this whole region right here all right just a friendly reminder from from the previous chapter now the next thing we want to talk about is Esters Esters are the dehydration synthesis products of other carboxilic acid derivatives and alcohols and they're named by placing the estery group the the the substituent that is bonded to the oxygen as a prefix and then the suffix 08 replaces OIC acid so what I'm going to do is I'm going to scroll here where we're talking about naming and then we'll come back and remind oursel of Fisher esterfication all right so they are named by placing the esterifying group as a prefix and then the suffix o it replaces OIC acid all right O8 replaces OIC acid so here we have two quick examples all right so here we have one two two carbons all right so we might be thinking if this was a carboxilic acid ethanoic acid but the OIC is repl replaced with O8 so E8 and then you have to address what is attached to that oxygen here all right what is what's the substituent that's bonded to that oxygen all right and that's going to be your prefix so here it's an ethyl group so this is ethyl ethano all right and same goes for this example as well here we have 1 2 3 four groups if this was a carboxilic acid at the end here as a terminal group we would call this butanoic acid but no this is an Esther so butanoic acid turns into butanoate all right and then you have to describe what's being attached what's bonded to this oxygen all right here it's an isopropyl group so this is isopropyl buttin O8 all right in addition to that something else that we briefly touched on last chapter that it's time to reiterate is that cyclic Esters are called lactones and they're named in the same manner as we as lact as lactum that we just saw and that's going to be the name of the precursor acid molecule is going to be included in the description of in the description of um the carbon atom that's bonded to the oxygen so here this would be you know beta lactone all right this would be like gamma lactone Delta lactone Etc and you could also associate that they're they're named in the same manner in that sense but also with the name of the precursor acid molecule included and so you wouldn't just say beta lactone you would say beta propiolactone propiolactone for this one for gamma this is gamma but buto sorry gamma butola tone Etc all right so that's how you would name cyclic Esters now because they lack hydrogen bonding Esters usually have a lower boiling point than their related carboxilic acids now we touched on this briefly in the previous um video but I am going to reiterate under acidic conditions mixtures of carboxilic acids with alcohols will condense into Esters and this reaction is called esterfication Esters can also technically be obtained from the reaction of anhydrides with alcohols but here this mechanism shows the interaction and the mixture of carboxilic acids with alcohols under acidic condition we talked about the reaction mechanism in the previous video I am I I have drawn it here to reiterate its importance and that you should be familiar with this reaction mechanism for the mcap now as a final point to to to this Esther section before we move into anhydrides I want to talk about Tri aial glycerols all right these Tri aial glycerols this is the storage form of fats in the body they are Esters of longchain carboxylic acids and glycerol saponification if you remember from the previous chapter is the process by which fats are hydrolyzed under basic conditions to produce soap so saponification of Tri aial glycerols all right a tri glyceride for example is going to yield glycerol and soap all right this is important to know treating trial glycerols with something like sodium uh hydroxide is going to produce fatty acid salts which we call soap as well as glycerol all right this is a process you should be familiar with you should know saponification of a trial glycerol what does it yield soap and glycerol fantastic with that we can move into discussing anhydrites anhydrites also called acid anhydrides are the condensation dimers of carboxilic acids these molecules they have the general formula r c o o o r now symmetrical and hydrides are going to be named by substituting the word anhydride for the word acid in a carboxilic acid and then when anhydrides are asymmetrical You're simply going to to name the two chains alphabetically followed by an hydride all right so here we can see two quick examples all right ethanoic propenoic and hydrate so we have 1 2 three on one side if this was a carboxilic acid you would call this ethanoic acid forget the acid so that side is ethanoic other side has two carbons if it was a carboxilic acid um sorry switch this around so sorry all right this side has three carbon that's you're thinking propane if it was a carboxilic acid you would be thinking propanoic acid for this anhydride this side would be referred to as propanoic just no acid the other side has two carbons you think ethane if it was a carboxilic acid ethanolic acid here this is a segment of your anhydrite so it would simply be called ethanoic and then you would put these two parts together alphabetically and then add an hydde and so the name of this molecule is ethanoic propenoic and hydride all right that's for asymmetrical and hydride for a symmetrical an hydr you just both sides are equivalent you just figure out um the name for one side this is two carbons you think ethane if it was a carboxilic acid ethanoic acid but it's a part of your anhydride so we just refer to it as ethanoic both sides all right ethanoic so you don't have to repeat it twice you just say ethanoic and hydride that's the name of this molecule now like previously said in in chapter 8 acid an hydrides are synthesized by a condensation reaction between two carboxilic acids with one water molecule uh with with one molecule of water that's lost in this condensation all right like demonstrated here now um something else that's important to knowe quickly I am going to kind of draw it out as we talk about about it is that you can have a inter intra molecular an hydride reaction happen and the byproduct of that is a cyclic anhydrate so for example if you had a molecule all right let me get out my pen if we had a molecule that looked something like this all right and say you treat this just with heat all right what could happen is an intr molecular anhydride formation all right where you have the same process happen as you would imagine with just two carboxilic acids reacting to carboxilic acid molecules reacting with the loss of a water molecule to form an an anhydride that is happening but all within this one molecule and as a consequence you would form the following anhydride molecule all right with water as a byproduct all right now something to note is that anhydrites often have higher boiling points than their related carboxilic acid based solely on their much greater weight all right with that we have reviewed and talked about further amides Esters and anhydrates let's quickly sum up all of the points we talked about all right we started with amides they are the condensation products of carboxilic acids and ammonia or amines amides are given the suffix amide in the Nom clature the alkal groups on a substituted amide are written at the beginning of the name all right with with the prefix n in addition we talked about cyclic amides they're called lactum and they're named by the Greek letter of the carbon forming the bond with the nitrogen then we moved into into Esters all right Esters are the condensation products of carboxilic acids with alcohols Fisher esterification like we covered in the previous chapter Esters are given the suffix 08 and the estery group is written as a substituent without a number cyclic Esters they're called lactones lactones are named by the number of carbons in the ring and the Greek letter of the carbon forming the bond with the oxygen lastly we also discussed under the category of Esters Tri AAL glycerols which are a form of fat storage and they include three Esther bonds between glycerol and fatty acids saponification is going to be the breakdown of fat using a strong base to form soap and specifically the saponification of Tri AAL glycerols gives you soap and glycerol and then lastly we discussed anhydrites they are the condensation diers of carboxylic acids symmetric an hydrides are named for their parent carboxilic acid followed by anhydride asymmetric an hydrides are named by listing the parent carboxilic acids alphabetically followed by anhydride now some cyclic anhydrides can be synthesized by heating dioic acids all right and we saw an example of that here near the end all right we're going to stop the video here in the next video we're going to cover objective 2 and objective three rea activity principles and nucleophilic acal substitution reactions let me know if you have any questions comments concerns down below other than that see you in the next video good luck happy studying and have a beautiful beautiful day future doctors